The following outline is provided as an overview of and topical guide to cryptography:

Cryptography

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

(or cryptology) – practice and study of hiding information

Information

Information in its most restricted technical sense is a message or collection of messages that consists of an ordered sequence of symbols, or it is the meaning that can be interpreted from such a message or collection of messages. Information can be recorded or transmitted. It can be recorded as...

. Modern cryptography intersects the disciplines of mathematics

Mathematics

Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

, computer science

Computer science

Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...

, and engineering

Engineering

Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

. Applications of cryptography include ATM cards

Automated teller machine

An automated teller machine or automatic teller machine, also known as a Cashpoint , cash machine or sometimes a hole in the wall in British English, is a computerised telecommunications device that provides the clients of a financial institution with access to financial transactions in a public...

, computer passwords

Password

A password is a secret word or string of characters that is used for authentication, to prove identity or gain access to a resource . The password should be kept secret from those not allowed access....

, and electronic commerce

Electronic commerce

Electronic commerce, commonly known as e-commerce, eCommerce or e-comm, refers to the buying and selling of products or services over electronic systems such as the Internet and other computer networks. However, the term may refer to more than just buying and selling products online...

.

Essence of cryptography

Main article: Cryptography

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

• Cryptographer –
• Encryption
  Encryption
  In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
  
  /Decryption –
• Cryptographic key –
• Cipher
  Cipher
  In cryptography, a cipher is an algorithm for performing encryption or decryption — a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. In non-technical usage, a “cipher” is the same thing as a “code”; however, the concepts...
  
   –
• Ciphertext
  Ciphertext
  In cryptography, ciphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher...
  
   –
• Plaintext
  Plaintext
  In cryptography, plaintext is information a sender wishes to transmit to a receiver. Cleartext is often used as a synonym. Before the computer era, plaintext most commonly meant message text in the language of the communicating parties....
  
   –
• Code
  Code
  A code is a rule for converting a piece of information into another form or representation , not necessarily of the same type....
  
   –
• Tabula recta
  Tabula recta
  In cryptography, the tabula recta is a square table of alphabets, each row of which is made by shifting the previous one to the left...
  
   –
• Alice and Bob
  Alice and Bob
  The names Alice and Bob are commonly used placeholder names for archetypal characters in fields such as cryptography and physics. The names are used for convenience; for example, "Alice sends a message to Bob encrypted with his public key" is easier to follow than "Party A sends a message to Party...
  
   –

Uses of cryptographic techniques

• Commitment scheme
  Commitment scheme
  In cryptography, a commitment scheme allows one to commit to a value while keeping it hidden, with the ability to reveal the committed value later. Commitments are used to bind a party to a value so that they cannot adapt to other messages in order to gain some kind of inappropriate advantage...
  
  s –
• Secure multiparty computation
  Secure multiparty computation
  Secure multi-party computation is a sub field of cryptography. The goal of methods for secure multi-party computation is to enable parties to jointly compute a function over their inputs, while at the same time keeping these inputs private...
  
  s –
• Electronic voting
  Electronic voting
  Electronic voting is a term encompassing several different types of voting, embracing both electronic means of casting a vote and electronic means of counting votes....
  
   –
• Authentication
  Authentication
  Authentication is the act of confirming the truth of an attribute of a datum or entity...
  
   –
• Digital signature
  Digital signature
  A digital signature or digital signature scheme is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, and that it was not altered in transit...
  
  s –
• Crypto systems –
• Dining cryptographers protocol – by David Chaum
  David Chaum
  David Chaum is the inventor of many cryptographic protocols, including blind signature schemes, commitment schemes, and digital cash. In 1982, Chaum founded the International Association for Cryptologic Research , which currently organizes academic conferences in cryptography research...
  
  
• Anonymous remailer
  Anonymous remailer
  An anonymous remailer is a server computer which receives messages with embedded instructions on where to send them next, and which forwards them without revealing where they originally came from...
  
   –
• Pseudonymity
  Pseudonymity
  Pseudonymity is a word derived from pseudonym, meaning 'false name', and anonymity, meaning unknown or undeclared source, describing a state of disguised identity. The pseudonym identifies a holder, that is, one or more human beings who possess but do not disclose their true names...
  
   –
• Anonymous internet banking
  Anonymous internet banking
  Anonymous Internet banking is the proposed use of strong financial cryptography to make electronic bank secrecy possible. The bank issues currency in the form of electronic tokens that can be converted on presentation to the bank to some other currency...
  
   –
• Onion routing
  Onion routing
  Onion routing is a technique for anonymous communication over a computer network. Messages are repeatedly encrypted and then sent through several network nodes called onion routers. Like someone unpeeling an onion, each onion router removes a layer of encryption to uncover routing instructions, and...
  
   –

Branches of cryptography

• Cryptographic engineering
  Cryptographic engineering
  Cryptographic engineering is the discipline of using cryptography to solve human problems. Cryptography is typically applied when trying to ensure data confidentiality, to authenticate people or devices, or to verify data integrity in risky environments....
  
   –
• Multivariate cryptography
  Multivariate Cryptography
  Multivariate cryptography is the generic term for asymmetric cryptographic primitives based on multivariate polynomials over finite fields. In certain cases those polynomials could be defined over both a ground and an extension field. If the polynomials have the degree two, we talk about...
  
   –
• Quantum cryptography
  Quantum cryptography
  Quantum key distribution uses quantum mechanics to guarantee secure communication. It enables two parties to produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages...
  
   –
• Steganography
  Steganography
  Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message, a form of security through obscurity...
  
   –
• Visual cryptography
  Visual cryptography
  Visual cryptography is a cryptographic technique which allows visual information to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers....
  
   –

History of cryptography

• Japanese cryptology from the 1500s to Meiji
  Japanese cryptology from the 1500s to Meiji
  The cipher system that Uesugi used is basically a simple substitution usually known as a Polybius square or “checkerboard.” The i-ro-ha alphabet contains forty-eight letters, so a seven-by-seven square is used, with one of the cells left blank. The rows and columns are labeled with a number or a...
  
   –
• World War I cryptography
  World War I cryptography
  Codes and ciphers were used extensively in World War I. The decoding by British Naval intelligence of the Zimmermann telegram helped bring the United States into the war....
  
   –
• World War II cryptography
  World War II cryptography
  Cryptography was used extensively during World War II, with a plethora of code and cipher systems fielded by the nations involved. In addition, the theoretical and practical aspects of cryptanalysis, or codebreaking, was much advanced....
  
   –
• Reservehandverfahren
  Reservehandverfahren
  ' was a German Naval World War II hand-cipher system used as a backup method when no working Enigma machine was available.The cipher had two stages: a transposition followed by bigram substitution. In the transposition stage, the cipher clerk would write out the plaintext into a "cage" — a shape...
  
   –
• Venona project
  Venona project
  The VENONA project was a long-running secret collaboration of the United States and United Kingdom intelligence agencies involving cryptanalysis of messages sent by intelligence agencies of the Soviet Union, the majority during World War II...
  
   –
• Ultra
  Ultra
  Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by "breaking" high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School at Bletchley Park. "Ultra" eventually became the standard...
  
   –

Classical

Substitution

Substitution cipher

In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the "units" may be single letters , pairs of letters, triplets of letters, mixtures of the above, and so forth...

s –

• Monoalphabetic substitution –
• Caesar
  Caesar cipher
  In cryptography, a Caesar cipher, also known as a Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number...
  
   –

• ROT13
  ROT13
  ROT13 is a simple substitution cipher used in online forums as a means of hiding spoilers, punchlines, puzzle solutions, and offensive materials from the casual glance. ROT13 has been described as the "Usenet equivalent of a magazine printing the answer to a quiz upside down"...
  
   –
  • Affine
    Affine cipher
    The affine cipher is a type of monoalphabetic substitution cipher, wherein each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter...
    
     –
  • Atbash –
  • Polyalphabetic substitution –
  • Vigenère
    Vigenère cipher
    The Vigenère cipher is a method of encrypting alphabetic text by using a series of different Caesar ciphers based on the letters of a keyword. It is a simple form of polyalphabetic substitution....
    
     –
  • Autokey
    Autokey cipher
    An autokey cipher is a cipher which incorporates the message into the key. There are two forms of autokey cipher: key autokey and text autokey ciphers. A key-autokey cipher uses previous members of the keystream to determine the next element in the keystream...
    
     –
  • Polygraphic
    Polygraphic substitution
    A polygraphic substitution is a cipher in which a uniform substitution is performed on blocks of letters. When the length of the block is specifically known, more precise terms are used: for instance, a cipher in which pairs of letters are substituted is bigraphic.As a concept, polygraphic...
    
     –
  • Playfair
    Playfair cipher
    The Playfair cipher or Playfair square is a manual symmetric encryption technique and was the first literal digraph substitution cipher. The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair who promoted the use of the cipher.The technique encrypts pairs of...
    
     – by Charles Wheatstone
    Charles Wheatstone
    Sir Charles Wheatstone FRS , was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope , and the Playfair cipher...
    
    
  • Hill
    Hill cipher
    In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra. Invented by Lester S. Hill in 1929, it was the first polygraphic cipher in which it was practical to operate on more than three symbols at once. The following discussion assumes an elementary...
    
     –

Transposition

Transposition cipher

In cryptography, a transposition cipher is a method of encryption by which the positions held by units of plaintext are shifted according to a regular system, so that the ciphertext constitutes a permutation of the plaintext. That is, the order of the units is changed...

 –

• Scytale
  Scytale
  In cryptography, a scytale is a tool used to perform a transposition cipher, consisting of a cylinder with a strip of parchment wound around it on which is written a message...
  
   –
• Grille
  Grille (cryptography)
  In the history of cryptography, a grille cipher was a technique for encrypting a plaintext by writing it onto a sheet of paper through a pierced sheet . The earliest known description is due to the polymath Girolamo Cardano in 1550...
  
   –
• Permutation
  Permutation cipher
  In classical cryptography, a permutation cipher is a transposition cipher in which the key is a permutation.To apply a cipher, a random permutation of size e is generated...
  
   –
• VIC
  VIC cipher
  The VIC cipher was a pencil and paper cipher used by the Soviet spy Reino Häyhänen, codenamed "VICTOR".It was arguably the most complex hand-operated cipher ever seen, when it was first discovered...
  
   – complex hand cypher used by at least one Soviet spy in the early 1950s; it proved quite secure for the time

Modern

Symmetric-key algorithms

• Stream ciphers

• A5/1
  A5/1
  A5/1 is a stream cipher used to provide over-the-air communication privacy in the GSM cellular telephone standard. It was initially kept secret, but became public knowledge through leaks and reverse engineering. A number of serious weaknesses in the cipher have been identified.-History and...
  
   & A5/2
  A5/2
  A5/2 is a stream cipher used to provide voice privacy in the GSM cellular telephone protocol.The cipher is based around a combination of four linear feedback shift registers with irregular clocking and a non-linear combiner.In 1999, Ian Goldberg and David A...
  
   – cyphers specified for the GSM cellular telephone standard
• BMGL –
• Chameleon –
• FISH
  FISH (cipher)
  The FISH stream cipher is a fast software based stream cipher using Lagged Fibonacci generators, plus a concept from the shrinking generator cipher. It was published by Siemens in 1993. FISH is quite fast in software and has a huge key length...
  
   – by Siemens AG
• WWII 'Fish' cyphers
  Fish (cryptography)
  Fish was the Allied codename for any of several German teleprinter stream ciphers used during World War II. Enciphered teleprinter traffic was used between German High Command and Army Group commanders in the field, so its intelligence value was of the highest strategic value to the Allies...
  
   –

• Geheimfernschreiber – WWII mechanical onetime pad by Siemens AG
  Siemens AG
  Siemens AG is a German multinational conglomerate company headquartered in Munich, Germany. It is the largest Europe-based electronics and electrical engineering company....
  
  , called STURGEON by Bletchley Park
  Bletchley Park
  Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
  
  
• Pike
  Pike (cipher)
  The Pike stream cipher was invented by Ross Anderson to be a "leaner and meaner" version of FISH after he broke FISH in 1994; the name is a humorous allusion to the Pike fish. The cipher combines ideas from A5 with the Lagged Fibonacci generators used in FISH. It is about 10% faster than FISH, yet...
  
   – improvement on FISH by Ross Anderson
• Schlusselzusatz
  Lorenz cipher
  The Lorenz SZ40, SZ42A and SZ42B were German rotor cipher machines used by the German Army during World War II. They were developed by C. Lorenz AG in Berlin. They implemented a Vernam stream cipher...
  
   – WWII mechanical onetime pad by Lorenz
  Lorenz
  Lorenz is an originally German name derived from the Roman surname, Laurentius, which mean "from Laurentum".Lorenz may refer to:-Music:* Christian "Flake" Lorenz, a German musician...
  
  , called tunny by Bletchley Park
  Bletchley Park
  Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
  
  
  • HELIX –
  • ISAAC
    ISAAC (cipher)
    ISAAC is a cryptographically secure pseudorandom number generator and a stream cipher designed by Robert J. Jenkins Jr. in 1996.- Operation :...
    
     – intended as a PRNG
  • Leviathan
    LEVIATHAN (cipher)
    LEVIATHAN is a stream cipher submitted to NESSIE by Scott Fluhrer and David McGrew. It is a seekable stream cipher, which means that the user may efficiently skip forward to any part of the keystream, much like CTR mode or Salsa20, but unlike those ciphers generating contiguous blocks of the...
    
     –
  • LILI-128
    LILI-128
    LILI-128 is an LFSR based synchronous stream cipher with a 128-bit key. On 13 November 2000, LILI-128 was presented at the NESSIE workshop. It is designed to be simple to implement in both software and hardware....
    
     –
  • MUGI
    MUGI
    In cryptography, MUGI is a pseudorandom number generator designed for use as a stream cipher. It has been recommended for Japanese government use by the CRYPTREC project.MUGI takes a 128-bit secret key and a 128-bit initial vector...
    
     – CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation
  • MULTI-S01
    MULTI-S01
    In cryptography, MULTI-S01 , is an encryption algorithm based on a pseudorandom number generator . MULTI-S01 is an encryption scheme preserving both confidentiality and data integrity. The scheme defines a pair of algorithms; the encryption, the corresponding decryption with verification...
    
     (CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation)
  • One-time pad
    One-time pad
    In cryptography, the one-time pad is a type of encryption, which has been proven to be impossible to crack if used correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit or character from a secret random key of the same length as the plaintext, resulting...
    
     – Vernam and Mauborgne, patented mid-'20s; an extreme stream cypher
  • Panama –
  • RC4 (ARCFOUR) – one of a series by Professor Ron Rivest of MIT; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommended limited to 128-bit key
• CipherSaber
  CipherSaber
  CipherSaber is a simple symmetric encryption protocol based on the RC4 stream cipher. Its goals are both technical and political: it gives reasonably strong protection of message confidentiality, yet it's designed to be simple enough that even novice programmers can memorize the algorithm and...
  
   – (RC4 variant with 10 byte random IV
  Initialization vector
  In cryptography, an initialization vector is a fixed-size input to a cryptographic primitive that is typically required to be random or pseudorandom...
  
  , easy to implement
  • Salsa20
    Salsa20
    Salsa20 is a stream cipher submitted to eSTREAM by Daniel Bernstein. It is built on a pseudorandom function based on 32-bit addition, bitwise addition and rotation operations, which maps a 256-bit key, a 64-bit nonce , and a 64-bit stream position to a 512-bit output...
    
     – an eSTREAM
    ESTREAM
    eSTREAM is a project to "identify new stream ciphers suitable for widespread adoption", organised by the EU ECRYPT network. It was set up as a result of the failure of all six stream ciphers submitted to the NESSIE project. The call for primitives was first issued in November 2004. The project was...
    
     recommended cipher
  • SEAL
    SEAL (cipher)
    In cryptography, SEAL is a very fast stream cipher optimised for machines with a 32-bit word size and plenty of RAM. SEAL is actually a pseudorandom function family in that it can easily generate arbitrary portions of the keystream without having to start from the beginning...
    
     –
  • SNOW
    SNOW
    SNOW 1.0, SNOW 2.0, and SNOW 3G are word-based synchronous stream ciphers developed by Thomas Johansson and Patrik Ekdahl at Lund University.-History:...
    
     –
  • SOBER
    SOBER
    In cryptography, SOBER is a family of stream ciphers initially designed by Greg Rose of QUALCOMM Australia starting in 1997. The name is a contrived acronym for Seventeen Octet Byte Enabled Register. Initially the cipher was intended as a replacement for broken ciphers in cellular telephony...
    
     –
• SOBER-t16 –
• SOBER-t32 –
  • WAKE

• Block ciphers

• Product cipher
  Product cipher
  In cryptography, a product cipher combines two or more transformations in a manner intending that the resulting cipher is more secure than the individual components to make it resistant to cryptanalysis. The product cipher combines a sequence of simple transformations such as substitution,...
  
   –
• Feistel cipher
  Feistel cipher
  In cryptography, a Feistel cipher is a symmetric structure used in the construction of block ciphers, named after the German-born physicist and cryptographer Horst Feistel who did pioneering research while working for IBM ; it is also commonly known as a Feistel network. A large proportion of block...
  
   – pattern by Horst Feistel
  Horst Feistel
  Horst Feistel was a German-born cryptographer who worked on the design of ciphers at IBM, initiating research that would culminate in the development of the Data Encryption Standard in the 1970s....
  
  
• Advanced Encryption Standard
  Advanced Encryption Standard
  Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...
  
   (Rijndael) – 128 bit block; NIST selection for the AES, FIPS 197, 2001—by Joan Daemen
  Joan Daemen
  Joan Daemen |Limburg]], Belgium) is a Belgian cryptographer and one of the designers of Rijndael, the Advanced Encryption Standard , together with Vincent Rijmen. He has also designed or co-designed the MMB, Square, SHARK, NOEKEON, 3-Way, and BaseKing block ciphers...
  
   and Vincent Rijmen
  Vincent Rijmen
  Vincent Rijmen is a Belgian cryptographer and one of the two designers of the Rijndael, the Advanced Encryption Standard. Rijmen is also the co-designer of the WHIRLPOOL cryptographic hash function, and the block ciphers Anubis, KHAZAD, Square, NOEKEON and SHARK.In 1993, Rijmen obtained a degree...
  
  ; NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection; CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation
• Anubis
  Anubis (cipher)
  Anubis is a block cipher designed by Vincent Rijmen and Paulo S. L. M. Barreto as an entrant in the NESSIE project. Anubis operates on data blocks of 128 bits, accepting keys of length 32N bits ....
  
   – 128-bit block
• BEAR – built from a stream cypher and hash function, by Ross Anderson
• Blowfish
  Blowfish (cipher)
  Blowfish is a keyed, symmetric block cipher, designed in 1993 by Bruce Schneier and included in a large number of cipher suites and encryption products. Blowfish provides a good encryption rate in software and no effective cryptanalysis of it has been found to date...
  
   – 64 bit block; by Bruce Schneier
  Bruce Schneier
  Bruce Schneier is an American cryptographer, computer security specialist, and writer. He is the author of several books on general security topics, computer security and cryptography, and is the founder and chief technology officer of BT Managed Security Solutions, formerly Counterpane Internet...
  
   et al.
• Camellia
  Camellia (cipher)
  In cryptography, Camellia is a 128-bit block cipher jointly developed by Mitsubishi and NTT. The cipher has been approved for use by the ISO/IEC, the European Union's NESSIE project and the Japanese CRYPTREC project...
  
   – 128 bit block; NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection (NTT & Mitsubishi Electric); CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation
• CAST-128
  CAST-128
  in cryptography, CAST-128 is a block cipher used in a number of products, notably as the default cipher in some versions of GPG and PGP. It has also been approved for Canadian government use by the Communications Security Establishment...
  
   (CAST5) – 64 bit block; one of a series of algorithms by Carlisle Adams
  Carlisle Adams
  Carlisle M. Adams is a cryptographer and computer security researcher. Formerly senior cryptographer at Entrust, he is currently a professor at the University of Ottawa. His notable work includes the design of the block ciphers CAST-128 and CAST-256. He also helped organize the first Selected...
  
   and Stafford Tavares
  Stafford Tavares
  Stafford Emanuel Tavares is a cryptographer, professor emeritus at Queen's University.His notable work includes the design of the block ciphers CAST-128 and CAST-256. He also helped organize the first Selected Areas in Cryptography workshop in 1994...
  
  , insistent that the name is not due to their initials

• CAST-256
  CAST-256
  In cryptography, CAST-256 is a block cipher published in June 1998. It was submitted as a candidate for the Advanced Encryption Standard ; however, it was not among the five AES finalists. It is an extension of an earlier cipher, CAST-128; both were designed according to the "CAST" design...
  
   (CAST6) – 128-bit block; the successor to CAST-128 and a candidate for the AES competition
  • CIPHERUNICORN-A
    CIPHERUNICORN-A
    In cryptography, CIPHERUNICORN-A is a block cipher created by NEC in 2000. It is among the cryptographic techniques recommended for Japanese government use by CRYPTREC....
    
     – 128 bit block; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation
  • CIPHERUNICORN-E
    CIPHERUNICORN-E
    In cryptography, CIPHERUNICORN-E is a block cipher created by NEC in 1998. It is among the cryptographic techniques recommended for Japanese government use by CRYPTREC....
    
     – 64 bit block; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation (limited)
  • CMEA – cipher used in US cellphones, found to have weaknesses.
  • CS-Cipher
    CS-Cipher
    In cryptography, CS-Cipher is a block cipher invented by Jacques Stern and Serge Vaudenay in 1998. It was submitted to the NESSIE project, but was not selected....
    
     – 64 bit block
  • Data Encryption Standard
    Data Encryption Standard
    The Data Encryption Standard is a block cipher that uses shared secret encryption. It was selected by the National Bureau of Standards as an official Federal Information Processing Standard for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is...
    
     (DES) – 64 bit block; FIPS 46-3, 1976
  • DEAL
    DEAL
    In cryptography, DEAL is a block cipher derived from the Data Encryption Standard . The design was proposed in a report by Lars Knudsen in 1998, and was submitted to the AES contest by Richard Outerbridge .DEAL is a Feistel network which uses DES as the...
    
     – an AES candidate derived from DES
  • DES-X
    DES-X
    In cryptography, DES-X is a variant on the DES block cipher intended to increase the complexity of a brute force attack using a technique called key whitening....
    
     – a variant of DES to increase the key size.
  • FEAL
    FEAL
    In cryptography, FEAL is a block cipher proposed as an alternative to the Data Encryption Standard , and designed to be much faster in software. The Feistel based algorithm was first published in 1987 by Akihiro Shimizu and Shoji Miyaguchi from NTT...
    
     –
  • GDES
    GDES
    In cryptography, the Generalized DES Scheme is a variant of the DES block cipher designed with the intention of speeding up the encryption process while improving its security...
    
     – a DES
    Data Encryption Standard
    The Data Encryption Standard is a block cipher that uses shared secret encryption. It was selected by the National Bureau of Standards as an official Federal Information Processing Standard for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is...
    
     variant designed to speed up encryption
  • Grand Cru
    Grand Cru (cipher)
    In cryptography, Grand Cru is a block cipher invented in 2000 by Johan Borst. It was submitted to the NESSIE project, but was not selected.Grand Cru is a 10-round substitution-permutation network based largely on Rijndael . It replaces a number of Rijndael's unkeyed operations with key-dependent...
    
     – 128 bit block
  • Hierocrypt-3 – 128 bit block; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation
  • Hierocrypt-L1 – 64 bit block; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation (limited)
  • IDEA NXT
    IDEA NXT
    In cryptography, the IDEA NXT algorithm is a block cipher designed by Pascal Junod and Serge Vaudenay of EPFL . It was conceived between 2001 and 2003, the project was originally named FOX and was published in 2003. In May 2005 it was announced by MediaCrypt under the name IDEA NXT...
    
     – project name FOX, 64-bit and 128-bit block family; Mediacrypt (Switzerland); by Pascal Junod & Serge Vaudenay
    Serge Vaudenay
    Serge Vaudenay is a well-known French cryptographer.Serge Vaudenay entered the École Normale Supérieure in Paris as a normalien student in 1989. In 1992, he passed the agrégation in mathematics. He did his PhD at the computer science laboratory of École Normale Supérieure, and defended it in 1995...
    
     of Swiss Institute of Technology Lausanne
  • International Data Encryption Algorithm
    International Data Encryption Algorithm
    In cryptography, the International Data Encryption Algorithm is a block cipher designed by James Massey of ETH Zurich and Xuejia Lai and was first described in 1991. As a block cipher, it is also symmetric. The algorithm was intended as a replacement for the Data Encryption Standard[DES]...
    
     (IDEA) – 64 bit block;James Massey
    James Massey
    James Lee Massey is an information theorist andcryptographer, Professor Emeritus of Digital Technology at ETH Zurich. His notable work...
    
     & X Lai of ETH
    Eth
    Eth is a letter used in Old English, Icelandic, Faroese , and Elfdalian. It was also used in Scandinavia during the Middle Ages, but was subsequently replaced with dh and later d. The capital eth resembles a D with a line through the vertical stroke...
    
     Zurich
  • Iraqi Block Cipher
    Iraqi block cipher
    In cryptography, the Iraqi block cipher was a block cipher published in C source code form by anonymous FTP upload around July 1999, and widely distributed on Usenet. It is a five round unbalanced Feistel cipher operating on a 256 bit block with a 160 bit key....
    
     (IBC) –
  • KASUMI – 64-bit block; based on MISTY1
    MISTY1
    In cryptography, MISTY1 is a block cipher designed in 1995 by Mitsuru Matsui and others for Mitsubishi Electric.MISTY1 is one of the selected algorithms in the European NESSIE project, and has been recommended for Japanese government use by the CRYPTREC project."MISTY" can stand for "Mitsubishi...
    
    , adopted for next generation W-CDMA
    W-CDMA
    W-CDMA , UMTS-FDD, UTRA-FDD, or IMT-2000 CDMA Direct Spread is an air interface standard found in 3G mobile telecommunications networks. It is the basis of Japan's NTT DoCoMo's FOMA service and the most-commonly used member of the UMTS family and sometimes used as a synonym for UMTS...
    
     cellular phone security
  • KHAZAD
    KHAZAD
    In cryptography, KHAZAD is a block cipher designed by Paulo S. L. M. Barreto together with Vincent Rijmen, one of the designers of the Advanced Encryption Standard . KHAZAD is named after Khazad-dûm, the fictional dwarven realm in the writings of J. R. R. Tolkien...
    
     – 64-bit block designed by Barretto and Rijmen
    Vincent Rijmen
    Vincent Rijmen is a Belgian cryptographer and one of the two designers of the Rijndael, the Advanced Encryption Standard. Rijmen is also the co-designer of the WHIRLPOOL cryptographic hash function, and the block ciphers Anubis, KHAZAD, Square, NOEKEON and SHARK.In 1993, Rijmen obtained a degree...
    
    
  • Khufu and Khafre
    Khufu and Khafre
    In cryptography, Khufu and Khafre are two block ciphers designed by Ralph Merkle in 1989 while working at Xerox's Palo Alto Research Center...
    
     – 64-bit block ciphers
  • LION
    Lion
    The lion is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg in weight, it is the second-largest living cat after the tiger...
    
     – block cypher built from stream cypher and hash function, by Ross Anderson
  • LOKI89/91
    LOKI
    In cryptography, LOKI89 and LOKI91 are block ciphers designed as possible replacements for the Data Encryption Standard . The ciphers were developed based on a body of work analysing DES, and are very similar to DES in structure...
    
     – 64-bit block ciphers
  • LOKI97
    LOKI97
    In cryptography, LOKI97 is a block cipher which was a candidate in the Advanced Encryption Standard competition. It is a member of the LOKI family of ciphers, earlier instances being LOKI89 and LOKI91...
    
     – 128-bit block cipher, AES candidate
  • Lucifer
    Lucifer (cipher)
    In cryptography, Lucifer was the name given to several of the earliest civilian block ciphers, developed by Horst Feistel and his colleagues at IBM. Lucifer was a direct precursor to the Data Encryption Standard...
    
     – by Tuchman et al. of IBM
    IBM
    International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
    
    , early 1970s; modified by NSA/NBS
    NBS
    NBS can stand for:*N-Bromosuccinimide, a chemical reagent*Nagano Broadcasting Systems, a television broadcasting network in Nagano Prefecture, Japan*The NASCAR Busch Series*A Nash bargaining solution, in economics, a solution to a Nash bargaining game...
    
     and released as DES
    Data Encryption Standard
    The Data Encryption Standard is a block cipher that uses shared secret encryption. It was selected by the National Bureau of Standards as an official Federal Information Processing Standard for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is...
    
    
  • MAGENTA
    MAGENTA
    In cryptography, MAGENTA is a symmetric key block cipher developed by Michael Jacobson Jr. and Klaus Huber for Deutsche Telekom. The name MAGENTA is an acronym for Multifunctional Algorithm for General-purpose Encryption and Network Telecommunication Applications...
    
     – AES candidate
  • Mars – AES finalist, by Don Coppersmith
    Don Coppersmith
    Don Coppersmith is a cryptographer and mathematician. He was involved in the design of the Data Encryption Standard block cipher at IBM, particularly the design of the S-boxes, strengthening them against differential cryptanalysis...
    
     et al.
  • MISTY1
    MISTY1
    In cryptography, MISTY1 is a block cipher designed in 1995 by Mitsuru Matsui and others for Mitsubishi Electric.MISTY1 is one of the selected algorithms in the European NESSIE project, and has been recommended for Japanese government use by the CRYPTREC project."MISTY" can stand for "Mitsubishi...
    
     – NESSIE
    NESSIE
    NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
    
     selection 64-bit block; Mitsubishi Electric (Japan); CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation (limited)
  • MISTY2 – 128 bit block: Mitsubishi Electric (Japan)
  • Nimbus
    Nimbus (cipher)
    In cryptography, Nimbus is a block cipher invented by Alexis Machado in 2000. It was submitted to the NESSIE project, but was not selected.The algorithm uses a 128-bit key. It operates on blocks of 64 bits and consists of 5 rounds of...
    
     – 64 bit block
  • NOEKEON
    Noekeon
    NOEKEON is a family of two block ciphers designed by Joan Daemen, Michaël Peeters, Gilles Van Assche and Vincent Rijmen and submitted to the NESSIE project in September 2000. The two ciphers are "direct mode" NOEKEON, to be used for maximum efficiency where related-key attacks are not possible,...
    
     – 128 bit block
  • NUSH
    NUSH
    In cryptography, NUSH is a block cipher invented by Anatoly Lebedev and Alexey Volchkov for the Russian company LAN Crypto. It was submitted to the NESSIE project, but was not selected....
    
     – variable block length (64 - 256 bits)
  • Q
    Q (cipher)
    In cryptography, Q is a block cipher invented by Leslie McBride. It was submitted to the NESSIE project, but was not selected.The algorithm uses a key size of 128, 192, or 256 bits. It operates on blocks of 128 bits using a substitution-permutation network structure. There are 8 rounds for a...
    
     – 128 bit block
  • RC2
    RC2
    In cryptography, RC2 is a block cipher designed by Ron Rivest in 1987. "RC" stands for "Ron's Code" or "Rivest Cipher"; other ciphers designed by Rivest include RC4, RC5 and RC6....
    
     – 64-bit block, variable key length
• RC6
  RC6
  In cryptography, RC6 is a symmetric key block cipher derived from RC5. It was designed by Ron Rivest, Matt Robshaw, Ray Sidney, and Yiqun Lisa Yin to meet the requirements of the Advanced Encryption Standard competition. The algorithm was one of the five finalists, and was also submitted to the...
  
   – variable block length; AES finalist, by Ron Rivest
  Ron Rivest
  Ronald Linn Rivest is a cryptographer. He is the Andrew and Erna Viterbi Professor of Computer Science at MIT's Department of Electrical Engineering and Computer Science and a member of MIT's Computer Science and Artificial Intelligence Laboratory...
  
   et al.
• RC5
  RC5
  In cryptography, RC5 is a block cipher notable for its simplicity. Designed by Ronald Rivest in 1994, RC stands for "Rivest Cipher", or alternatively, "Ron's Code"...
  
   – Ron Rivest
  Ron Rivest
  Ronald Linn Rivest is a cryptographer. He is the Andrew and Erna Viterbi Professor of Computer Science at MIT's Department of Electrical Engineering and Computer Science and a member of MIT's Computer Science and Artificial Intelligence Laboratory...
  
  
  • SAFER
    SAFER
    In cryptography, SAFER is the name of a family of block ciphers designed primarily by James Massey on behalf of Cylink Corporation. The early SAFER K and SAFER SK designs share the same encryption function, but differ in the number of rounds and the key schedule...
    
     – variable block length
  • SC2000
    SC2000
    In cryptography, SC2000 is a block cipher invented by a research group at Fujitsu Labs. It was submitted to the NESSIE project, but was not selected. SC2000 is one of the cryptographic techniques recommended for Japanese government use by CRYPTREC....
    
     – 128 bit block; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation
  • Serpent
    Serpent (cipher)
    Serpent is a symmetric key block cipher which was a finalist in the Advanced Encryption Standard contest, where it came second to Rijndael. Serpent was designed by Ross Anderson, Eli Biham, and Lars Knudsen....
    
     – 128 bit block; AES finalist by Ross Anderson, Eli Biham
    Eli Biham
    Eli Biham is an Israeli cryptographer and cryptanalyst, currently a professor at the Technion Israeli Institute of Technology Computer Science department. Starting from October 2008, Biham is the dean of the Technion Computer Science department, after serving for two years as chief of CS graduate...
    
    , Lars Knudsen
    Lars Knudsen
    Lars Ramkilde Knudsen is a Danish researcher in cryptography, particularly interested in the design and analysis of block ciphers, hash functions and message authentication codes .-Academic:...
    
    
  • SHACAL-1 – 160-bit block
  • SHACAL-2 – 256-bit block cypher; NESSIE
    NESSIE
    NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
    
     selection Gemplus (France)
  • Shark – grandfather of Rijndael/AES
    Advanced Encryption Standard
    Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...
    
    , by Daemen and Rijmen
• Square
  Square (cipher)
  In cryptography, Square is a block cipher invented by Joan Daemen and Vincent Rijmen. The design, published in 1997, is a forerunner to the Rijndael algorithm, which has been adopted as the Advanced Encryption Standard...
  
   – father of Rijndael/AES
  Advanced Encryption Standard
  Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...
  
  , by Daemen and Rijmen
  • TEA
    Tiny Encryption Algorithm
    In cryptography, the Tiny Encryption Algorithm is a block cipher notable for its simplicity of description and implementation, typically a few lines of code...
    
     – by David Wheeler & Roger Needham
    Roger Needham
    Roger Michael Needham, CBE, FRS, FREng was a British computer scientist.-Early life:He attended Doncaster Grammar School for Boys in Doncaster ....
    
    
  • Triple DES
    Triple DES
    In cryptography, Triple DES is the common name for the Triple Data Encryption Algorithm block cipher, which applies the Data Encryption Standard cipher algorithm three times to each data block....
    
     – by Walter Tuchman
    Walter Tuchman
    Walter Tuchman led the Data Encryption Standard development team at IBM. He was also responsible for the development of Triple DES.-See also:* Horst Feistel...
    
    , leader of the Lucifer
    Lucifer (cipher)
    In cryptography, Lucifer was the name given to several of the earliest civilian block ciphers, developed by Horst Feistel and his colleagues at IBM. Lucifer was a direct precursor to the Data Encryption Standard...
    
     design team—not all triple uses of DES increase security, Tuchman's does; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation (limited), only when used as in FIPS Pub 46-3
  • Twofish
    Twofish
    In cryptography, Twofish is a symmetric key block cipher with a block size of 128 bits and key sizes up to 256 bits. It was one of the five finalists of the Advanced Encryption Standard contest, but was not selected for standardisation...
    
     – 128 bit block; AES finalist by Bruce Schneier
    Bruce Schneier
    Bruce Schneier is an American cryptographer, computer security specialist, and writer. He is the author of several books on general security topics, computer security and cryptography, and is the founder and chief technology officer of BT Managed Security Solutions, formerly Counterpane Internet...
    
     et al.
  • XTEA
    XTEA
    In cryptography, XTEA is a block cipher designed to correct weaknesses in TEA. The cipher's designers were David Wheeler and Roger Needham of the Cambridge Computer Laboratory, and the algorithm was presented in an unpublished technical report in 1997...
    
     – by David Wheeler & Roger Needham
    Roger Needham
    Roger Michael Needham, CBE, FRS, FREng was a British computer scientist.-Early life:He attended Doncaster Grammar School for Boys in Doncaster ....
    
    
  • 3-Way
    3-Way
    In cryptography, 3-Way is a block cipher designed in 1994 by Joan Daemen, who also designed Rijndael, the winner of NIST's Advanced Encryption Standard contest....
    
     – 96 bit block by Joan Daemen
    Joan Daemen
    Joan Daemen |Limburg]], Belgium) is a Belgian cryptographer and one of the designers of Rijndael, the Advanced Encryption Standard , together with Vincent Rijmen. He has also designed or co-designed the MMB, Square, SHARK, NOEKEON, 3-Way, and BaseKing block ciphers...
    
    

• Polyalphabetic substitution machine cyphers
• Enigma – WWII German rotor cypher machine—many variants, any user networks for most of the variants
• Purple – highest security WWII Japanese Foreign Office cypher machine; by Japanese Navy Captain
• SIGABA
  SIGABA
  In the history of cryptography, the ECM Mark II was a cipher machine used by the United States for message encryption from World War II until the 1950s...
  
   – WWII US cypher machine by William Friedman, Frank Rowlett
  Frank Rowlett
  Frank Byron Rowlett was an American cryptologist.Rowlett was born in Rose Hill, Virginia and attended Emory & Henry College in Emory, Virginia, where he was a member of the Beta Lambda Zeta fraternity. In 1929 he received a bachelor's degree in mathematics and chemistry...
  
   et al.
• TypeX
  Typex
  In the history of cryptography, Typex machines were British cipher machines used from 1937. It was an adaptation of the commercial German Enigma with a number of enhancements that greatly increased its security....
  
   – WWII UK cypher machine

• Hybrid code/cypher combinations
• JN-25
  JN-25
  The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well...
  
   – WWII Japanese Navy superencyphered code; many variants
• Naval Cypher 3 – superencrypted code used by the Royal Navy in the 30s and into WWII

Asymmetric key algorithms

• ACE-KEM – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection asymmetric encryption scheme; IBM Zurich Research)

• ACE Encrypt
  ACE Encrypt
  ACE  — the collection of units, implementing both a public key encryption scheme and a digital signature scheme. Corresponding names for these schemes — «ACE Encrypt» and «ACE Sign». Schemes are based on Cramer-Shoup public key encryption scheme and Cramer-Shoup signature scheme...
  
   –
  • Chor-Rivest –
  • Diffie-Hellman – key agreement; CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation
  • El Gamal – discrete logarithm
  • Elliptic curve cryptography
    Elliptic curve cryptography
    Elliptic curve cryptography is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. The use of elliptic curves in cryptography was suggested independently by Neal Koblitz and Victor S...
    
     – (discrete logarithm variant
  • PSEC-KEM – NESSIE
    NESSIE
    NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
    
     selection asymmetric encryption scheme; NTT (Japan); CRYPTREC
    CRYPTREC
    CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
    
     recommendation only in DEM construction w/SEC1 parameters
• ECIES – Elliptic Curve Integrated Encryption System, Certicom Corporation
• ECIES-KEM –
• ECDH – Elliptic Curve Diffie-Hellman key agreement, CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation
  • EPOC
    Efficient Probabilistic Public-Key Encryption Scheme
    EPOC is a probabilistic public-key encryption scheme.EPOC was developed in 1999 by T. Okamoto, S. Uchiyama and E. Fujisaki of NTT Labs in Japan...
    
     –
  • Merkle–Hellman knapsack cryptosystem – knapsack scheme
  • McEliece –
  • Niederreiter cryptosystem
    Niederreiter cryptosystem
    In cryptography, the Niederreiter cryptosystem is a variation of the McEliece Cryptosystem developed in 1986 by Harald Niederreiter. It applies the same idea to the parity check matrix H of a linear code....
    
     –
  • NTRUEncrypt
    NTRUEncrypt
    The NTRUEncrypt public key cryptosystem, also known as the NTRU encryption algorithm, is a lattice-based alternative to RSA and ECC and is based on the shortest vector problem in a lattice...
    
     –
  • RSA – factoring
• RSA-KEM – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection asymmetric encryption scheme; ISO/IEC 18033-2 draft
• RSA-OAEP – CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation
  • Rabin cryptosystem
    Rabin cryptosystem
    The Rabin cryptosystem is an asymmetric cryptographic technique, whose security, like that of RSA, is related to the difficulty of factorization. However the Rabin cryptosystem has the advantage that the problem on which it relies has been proved to be as hard as integer factorization, which is...
    
     – factoring
• Rabin-SAEP –
• HIME(R) –
  • Threshold cryptosystem
    Threshold cryptosystem
    In cryptography, a cryptosystem is called a 'threshold cryptosystem', if in order to decrypt an encrypted message a number of parties exceeding a threshold is required to cooperate in the decryption protocol. The message is encrypted using a public key and the corresponding private key is shared...
    
     –
  • XTR
    XTR
    In cryptography, XTR is an algorithm for public-key encryption. XTR stands for ‘ECSTR’, which is an abbreviation for Efficient and Compact Subgroup Trace Representation. It is a method to represent elements of a subgroup of a multiplicative group of a finite field...
    
     –

Keys

Authentication

• Public key infrastructure
  Public key infrastructure
  Public Key Infrastructure is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates. In cryptography, a PKI is an arrangement that binds public keys with respective user identities by means of a certificate...
  
   –
• X.509
  X.509
  In cryptography, X.509 is an ITU-T standard for a public key infrastructure and Privilege Management Infrastructure . X.509 specifies, amongst other things, standard formats for public key certificates, certificate revocation lists, attribute certificates, and a certification path validation...
  
   –
• Public key certificate
  Public key certificate
  In cryptography, a public key certificate is an electronic document which uses a digital signature to bind a public key with an identity — information such as the name of a person or an organization, their address, and so forth...
  
   –
• Certificate authority
  Certificate authority
  In cryptography, a certificate authority, or certification authority, is an entity that issues digital certificates. The digital certificate certifies the ownership of a public key by the named subject of the certificate...
  
   –
• Certificate revocation list
  Certificate revocation list
  In the operation of some cryptosystems, usually public key infrastructures , a certificate revocation list is a list of certificates that have been revoked, and therefore should not be relied upon.-Revocation States:There are two different states of revocation defined in RFC 3280:* Revoked: A...
  
   –
• ID-based cryptography
  ID-based cryptography
  ID-based encryption is an important primitive of ID-based cryptography. As such it is a type of public-key encryption in which the public key of a user is some unique information about the identity of the user...
  
   –
• Certificate-based encryption
  Certificate-based encryption
  Certificate-based encryption is a system in which a certificate authority uses ID-based cryptography to produce a certificate. This system gives the users both implicit and explicit certification, the certificate can be used as a conventional certificate , but also implicitly for the purpose of...
  
   –
• Secure key issuing cryptography
  Secure key issuing cryptography
  Secure key issuing is variant of ID-based cryptography that reduces the level of trust that needs to be placed in a trusted third party by spreading the trust across multiple third parties. In addition to the normally transmitted information the user supplies what is known as "blinding"...
  
   –
• Certificateless cryptography
  Certificateless cryptography
  Certificateless cryptography is a variant of ID-based cryptography intended to prevent the key escrow problem. Ordinarily, keys are generated by a certificate authority or a key generation center who is given complete power and is implicitly trusted...
  
   –
• Merkle tree
  Hash tree
  In cryptography and computer science Hash trees or Merkle trees are a type of data structure which contains a tree of summary information about a larger piece of data – for instance a file – used to verify its contents. Hash trees are a combination of hash lists and hash chaining, which in turn are...
  
   –

Transport/exchange

• Diffie–Hellman –
• Man-in-the-middle attack
  Man-in-the-middle attack
  In cryptography, the man-in-the-middle attack , bucket-brigade attack, or sometimes Janus attack, is a form of active eavesdropping in which the attacker makes independent connections with the victims and relays messages between them, making them believe that they are talking directly to each other...
  
   –
• Needham–Schroeder –
• Offline private key
  Offline private key
  An offline private key is a cryptographic key that is not stored on a network-connected medium. The key can be used to decrypt archive or backup data.The key can be the result of an offline private key protocol. In printed form the key can be a trusted paper key....
  
   –
• Otway–Rees –
• Trusted paper key
  Trusted paper key
  A paper key is a machine-readable print of a cryptographic key. The printed key can be used to decrypt data, e.g. archives or backup data. A paper key can be the result of an offline private key protocol...
  
   –
• Wide Mouth Frog –

Weak keys

• Brute force attack
  Brute force attack
  In cryptography, a brute-force attack, or exhaustive key search, is a strategy that can, in theory, be used against any encrypted data. Such an attack might be utilized when it is not possible to take advantage of other weaknesses in an encryption system that would make the task easier...
  
   –
• Dictionary attack
  Dictionary attack
  In cryptanalysis and computer security, a dictionary attack is a technique for defeating a cipher or authentication mechanism by trying to determine its decryption key or passphrase by searching likely possibilities.-Technique:...
  
   –
• Related key attack –
• Key derivation function
  Key derivation function
  In cryptography, a key derivation function derives one or more secret keys from a secret value such as a master key or other known information such as a password or passphrase using a pseudo-random function...
  
   –
• Key strengthening
  Key strengthening
  In cryptography, key stretching refers to techniques used to make a possibly weak key, typically a password or passphrase, more secure against a brute force attack by increasing the time it takes to test each possible key. Passwords or passphrases created by humans are often short or predictable...
  
   –
• Password
  Password
  A password is a secret word or string of characters that is used for authentication, to prove identity or gain access to a resource . The password should be kept secret from those not allowed access....
  
   –
• Password-authenticated key agreement
  Password-authenticated key agreement
  In cryptography, a password-authenticated key agreement method is an interactive method for two or more parties to establish cryptographic keys based on one or more party's knowledge of a password.-Types:...
  
   –
• Passphrase
  Passphrase
  A passphrase is a sequence of words or other text used to control access to a computer system, program or data. A passphrase is similar to a password in usage, but is generally longer for added security. Passphrases are often used to control both access to, and operation of, cryptographic programs...
  
   –
• Salt
  Salt (cryptography)
  In cryptography, a salt consists of random bits, creating one of the inputs to a one-way function. The other input is usually a password or passphrase. The output of the one-way function can be stored rather than the password, and still be used for authenticating users. The one-way function...
  
   –

Cryptographic hash functions

• Message authentication code
  Message authentication code
  In cryptography, a message authentication code is a short piece of information used to authenticate a message.A MAC algorithm, sometimes called a keyed hash function, accepts as input a secret key and an arbitrary-length message to be authenticated, and outputs a MAC...
  
   –
• Keyed-hash message authentication code –
• EMAC
  EMac
  The eMac, short for education Mac, was a Macintosh desktop computer made by Apple Inc. It was originally aimed at the education market, but was later made available as a cheaper mass market alternative to Apple's second-generation LCD display iMac....
  
   – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection MAC
• HMAC
  HMAC
  In cryptography, HMAC is a specific construction for calculating a message authentication code involving a cryptographic hash function in combination with a secret key. As with any MAC, it may be used to simultaneously verify both the data integrity and the authenticity of a message...
  
   – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection MAC; ISO/IEC 9797-1
  ISO/IEC 9797-1
  ISO/IEC 9797-1 Information technology — Security techniques — Message Authentication Codes — Part 1: Mechanisms using a block cipher is an international standard that defines methods for calculating a message authentication code over data.Rather than defining one specific...
  
  , FIPS PUB 113 and IETF RFC
  Request for Comments
  In computer network engineering, a Request for Comments is a memorandum published by the Internet Engineering Task Force describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.Through the Internet Society, engineers and...
  
  
• TTMAC – (Two-Track-MAC) NESSIE selection MAC; K.U.Leuven (Belgium) & debis AG (Germany)
• UMAC
  UMAC
  In cryptography, a message authentication code based on universal hashing, or UMAC, is a type of message authentication code calculated choosing a hash function from a class of hash functions according to some secret process and applying it to the message. The resulting digest or fingerprint is...
  
   – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection MAC; Intel, UNevada Reno, IBM, Technion, & UC Davis
• MD5
  MD5
  The MD5 Message-Digest Algorithm is a widely used cryptographic hash function that produces a 128-bit hash value. Specified in RFC 1321, MD5 has been employed in a wide variety of security applications, and is also commonly used to check data integrity...
  
   – one of a series of message digest algorithms by Prof Ron Rivest
  Ron Rivest
  Ronald Linn Rivest is a cryptographer. He is the Andrew and Erna Viterbi Professor of Computer Science at MIT's Department of Electrical Engineering and Computer Science and a member of MIT's Computer Science and Artificial Intelligence Laboratory...
  
   of MIT; 128 bit digest
• SHA-1 – developed at NSA 160-bit digest, an FIPS standard; the first released version was defective and replaced by this; NIST/NSA have released several variants with longer 'digest' lengths; CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation (limited)
• SHA-256 – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection hash function, FIPS 180-2, 256 bit digest; CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation
• SHA-384 – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection hash function, FIPS 180-2, 384 bit digest; CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation
• SHA-512 – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection hash function, FIPS 180-2, 512 bit digest; CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation
• RIPEMD-160 – developed in Europe for the RIPE project, 160-bit digest;CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   recommendation (limited)
• Tiger
  Tiger (hash)
  In cryptography, Tiger is a cryptographic hash function designed by Ross Anderson and Eli Biham in 1995 for efficiency on 64-bit platforms. The size of a Tiger hash value is 192 bits. Truncated versions can be used for compatibility with protocols assuming a particular hash size...
  
   – by Ross Anderson et al.
• Snefru –
• Whirlpool – NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   selection hash function, Scopus Tecnologia S.A. (Brazil) & K.U.Leuven (Belgium)

Cryptanalysis

Classical

• Frequency analysis
  Frequency analysis
  In cryptanalysis, frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers....
  
   –
• Contact analysis –
• Index of coincidence
  Index of coincidence
  In cryptography, coincidence counting is the technique of putting two texts side-by-side and counting the number of times that identical letters appear in the same position in both texts...
  
   –
• Kasiski examination
  Kasiski examination
  In cryptanalysis, Kasiski examination is a method of attacking polyalphabetic substitution ciphers, such as the Vigenère cipher...
  
   –

Modern

• Symmetric algorithms
• Boomerang attack
  Boomerang attack
  In cryptography, the boomerang attack is a method for the cryptanalysis of block ciphers based on differential cryptanalysis. The attack was published in 1999 by David Wagner, who used it to break the COCONUT98 cipher....
  
   –
• Brute force attack
  Brute force attack
  In cryptography, a brute-force attack, or exhaustive key search, is a strategy that can, in theory, be used against any encrypted data. Such an attack might be utilized when it is not possible to take advantage of other weaknesses in an encryption system that would make the task easier...
  
   –
• Davies' attack
  Davies' attack
  In cryptography, is a dedicated statistical cryptanalysis method for attacking the Data Encryption Standard . The attack was originally created in 1987 by Donald Davies. In 1994, Eli Biham and Alex Biryukov made significant improvements to the technique. It is a known-plaintext attack based on the...
  
   –
• Differential
  Differential cryptanalysis
  Differential cryptanalysis is a general form of cryptanalysis applicable primarily to block ciphers, but also to stream ciphers and cryptographic hash functions. In the broadest sense, it is the study of how differences in an input can affect the resultant difference at the output...
  
   –
• Impossible differential
  Impossible differential cryptanalysis
  In cryptography, impossible differential cryptanalysis is a form of differential cryptanalysis for block ciphers. While ordinary differential cryptanalysis tracks differences that propagate through the cipher with greater than expected probability, impossible differential cryptanalysis exploits...
  
   –
• Integral
  Integral cryptanalysis
  In cryptography, integral cryptanalysis is a cryptanalytic attack that is particularly applicable to block ciphers based on substitution-permutation networks. It was originally designed by Lars Knudsen as a dedicated attack against Square, so is commonly known as the Square attack. It was also...
  
   –
• Linear
  Linear cryptanalysis
  In cryptography, linear cryptanalysis is a general form of cryptanalysis based on finding affine approximations to the action of a cipher. Attacks have been developed for block ciphers and stream ciphers...
  
   –
• Meet-in-the-middle attack
  Meet-in-the-middle attack
  The meet-in-the-middle attack is a cryptographic attack which, like the birthday attack, makes use of a space-time tradeoff. While the birthday attack attempts to find two values in the domain of a function that map to the same value in its range, the meet-in-the-middle attack attempts to find a...
  
   –
• Mod-n –
• Related-key attack
  Related-key attack
  In cryptography, a related-key attack is any form of cryptanalysis where the attacker can observe the operation of a cipher under several different keys whose values are initially unknown, but where some mathematical relationship connecting the keys is known to the attacker...
  
   –
• Slide attack
  Slide attack
  The slide attack is a form of cryptanalysis designed to deal with the prevailing idea that even weak ciphers can become very strong by increasing the number of rounds, which can ward off a differential attack. The slide attack works in such a way as to make the number of rounds in a cipher irrelevant...
  
   –
• XSL attack
  XSL attack
  In cryptography, the XSL attack is a method of cryptanalysis for block ciphers. The attack was first published in 2002 by researchers Nicolas Courtois and Josef Pieprzyk. It has caused some controversy as it was claimed to have the potential to break the Advanced Encryption Standard cipher—also...
  
   –

• Hash functions:
• Birthday attack
  Birthday attack
  A birthday attack is a type of cryptographic attack that exploits the mathematics behind the birthday problem in probability theory. This attack can be used to abuse communication between two or more parties...
  
  

• Attack model
  Attack model
  Attack models or attack types specify how much information a cryptanalyst has access to when cracking an encrypted message...
  
  s
• Chosen-ciphertext
  Chosen-ciphertext attack
  A chosen-ciphertext attack is an attack model for cryptanalysis in which the cryptanalyst gathers information, at least in part, by choosing a ciphertext and obtaining its decryption under an unknown key. In the attack, an adversary has a chance to enter one or more known ciphertexts into the...
  
   –
• Chosen-plaintext
  Chosen-plaintext attack
  A chosen-plaintext attack is an attack model for cryptanalysis which presumes that the attacker has the capability to choose arbitrary plaintexts to be encrypted and obtain the corresponding ciphertexts. The goal of the attack is to gain some further information which reduces the security of the...
  
   –
• Ciphertext-only
  Ciphertext-only attack
  In cryptography, a ciphertext-only attack or known ciphertext attack is an attack model for cryptanalysis where the attacker is assumed to have access only to a set of ciphertexts....
  
   –
• Known-plaintext
  Known-plaintext attack
  The known-plaintext attack is an attack model for cryptanalysis where the attacker has samples of both the plaintext , and its encrypted version . These can be used to reveal further secret information such as secret keys and code books...
  
   –

• Side channel attack
  Side channel attack
  In cryptography, a side channel attack is any attack based on information gained from the physical implementation of a cryptosystem, rather than brute force or theoretical weaknesses in the algorithms...
  
  s
• Power analysis
  Power analysis
  In cryptography, power analysis is a form of side channel attack in which the attacker studies the power consumption of a cryptographic hardware device...
  
   –
• Timing attack
  Timing attack
  In cryptography, a timing attack is a side channel attack in which the attacker attempts to compromise a cryptosystem by analyzing the time taken to execute cryptographic algorithms...
  
   –

• Network attacks
• Man-in-the-middle attack
  Man-in-the-middle attack
  In cryptography, the man-in-the-middle attack , bucket-brigade attack, or sometimes Janus attack, is a form of active eavesdropping in which the attacker makes independent connections with the victims and relays messages between them, making them believe that they are talking directly to each other...
  
   –
• Replay attack
  Replay attack
  A replay attack is a form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed. This is carried out either by the originator or by an adversary who intercepts the data and retransmits it, possibly as part of a masquerade attack by IP packet...
  
   –

• External attacks
• Black-bag
  Black-bag cryptanalysis
  In cryptography, black-bag cryptanalysis is a euphemism for the acquisition of cryptographic secrets via burglary, or the covert installation of keystroke logging or trojan horse software/hardware on target computers or ancillary devices...
  
   –
• Rubber-hose
  Rubber-hose cryptanalysis
  In cryptography, rubber-hose cryptanalysis is the extraction of cryptographic secrets from a person by coercion or torture, in contrast to a mathematical or technical cryptanalytic attack....
  
   –

Robustness properties

• Provable security
  Provable security
  In cryptography, a system has provable security if its security requirements can be stated formally in an adversarial model, as opposed to heuristically, with clear assumptions that the adversary has access to the system as well as enough computational resources...
  
   –
• Random oracle model
  Random oracle
  In cryptography, a random oracle is an oracle that responds to every query with a random response chosen uniformly from its output domain, except that for any specific query, it responds the same way every time it receives that query...
  
   –
• Ciphertext indistinguishability
  Ciphertext indistinguishability
  Ciphertext indistinguishability is a property of many encryption schemes. Intuitively, if a cryptosystem possesses the property of indistinguishability, then an adversary will be unable to distinguish pairs of ciphertexts based on the message they encrypt...
  
   –
• Semantic security
  Semantic security
  Semantic security is a widely used definition for security in an asymmetric key encryption algorithm. For a cryptosystem to be semantically secure, it must be infeasible for a computationally bounded adversary to derive significant information about a message when given only its ciphertext and...
  
   –
• Malleability
  Malleability (cryptography)
  Malleability is a property of some cryptographic algorithms. An encryption algorithm is malleable if it is possible for an adversary to transform a ciphertext into another ciphertext which decrypts to a related plaintext...
  
   –

Uncracked codes and ciphers

• Beale ciphers
  Beale ciphers
  The Beale ciphers are a set of three ciphertexts, one of which allegedly states the location of a buried treasure of gold, silver and jewels estimated to be worth over USD$63 million as of September, 2011. The other two ciphertexts allegedly describe the content of the treasure, and list the names...
  
   –
• Chaocipher
  Chaocipher
  The Chaocipher is a cipher method invented by J. F. Byrne in 1918 and described in his 1953 autobiographical Silent Years. He believed Chaocipher was simple, yet unbreakable. Byrne stated that the machine he used to encipher his messages could be fitted into a cigar box...
  
   –
• D'Agapeyeff
  D'Agapeyeff cipher
  The D'Agapeyeff cipher is an as-yet unbroken cipher that appears in the first edition of Codes and Ciphers, an elementary book on cryptography published by the Russian-born English cartographer Alexander D'Agapeyeff in 1939....
  
   –
• Dorabella Cipher
  Dorabella Cipher
  The Dorabella Cipher is an enciphered letter written by Edward Elgar to Miss Dora Penny, which was accompanied by another dated July 14, 1897. Penny was never able to decipher it and its meaning remains unknown to this day....
  
   –
• Rongorongo
  Rongorongo
  Rongorongo is a system of glyphs discovered in the 19th century on Easter Island that appears to be writing or proto-writing. It cannot be read despite numerous attempts at decipherment. Although some calendrical and what might prove to be genealogical information has been identified, not even...
  
   –
• Shugborough inscription
  Shugborough inscription
  The Shugborough inscription is a sequence of letters - O U O S V A V V, between the letters D M - carved on the 18th-century Shepherd's Monument in the grounds of Shugborough Hall in Staffordshire, England, below a mirror image of Nicolas Poussin's painting, the Shepherds of Arcadia...
  
   –
• Voynich manuscript
  Voynich manuscript
  The Voynich manuscript, described as "the world's most mysterious manuscript", is a work which dates to the early 15th century, possibly from northern Italy. It is named after the book dealer Wilfrid Voynich, who purchased it in 1912....
  
   –

Organizations and selection projects

Standards

• Federal Information Processing Standard
  Federal Information Processing Standard
  A Federal Information Processing Standard is a publicly announced standardization developed by the United States federal government for use in computer systems by all non-military government agencies and by government contractors, when properly invoked and tailored on a contract...
  
  s Publication Program – run by NIST to produce standards in many areas to guide operations of the US Federal government; many FIPS
  Federal Information Processing Standard
  A Federal Information Processing Standard is a publicly announced standardization developed by the United States federal government for use in computer systems by all non-military government agencies and by government contractors, when properly invoked and tailored on a contract...
  
   publications are ongoing and related to cryptography
• ANSI
  American National Standards Institute
  The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...
  
   – standardization process that produces many standards in many areas; some are cryptography related, ongoing)
• ISO
  International Organization for Standardization
  The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
  
   – standardization process produces many standards in many areas; some are cryptography related, ongoing
• IEEE – standardization process produces many standards in many areas; some are cryptography related, ongoing
• IETF – standardization process that produces many standards called RFCs
  Request for Comments
  In computer network engineering, a Request for Comments is a memorandum published by the Internet Engineering Task Force describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.Through the Internet Society, engineers and...
  
  ) in many areas; some are cryptography related, ongoing)

General cryptographic

• NSA – internal evaluation/selections, charged with assisting NIST in its cryptographic responsibilities
• GCHQ – internal evaluation/selections, a division is charged with developing and recommending cryptographic standards for the UK government
• DSD
  Defence Signals Directorate
  Defence Signals Directorate is an Australian government intelligence agency responsible for signals intelligence and information security .-Overview:According to its website, DSD has two principal functions:...
  
   – Australian SIGINT
  SIGINT
  Signals intelligence is intelligence-gathering by interception of signals, whether between people , whether involving electronic signals not directly used in communication , or combinations of the two...
  
   agency, part of ECHELON
  ECHELON
  ECHELON is a name used in global media and in popular culture to describe a signals intelligence collection and analysis network operated on behalf of the five signatory states to the UK–USA Security Agreement...
  
  
• Communications Security Establishment
  Communications Security Establishment
  The Communications Security Establishment Canada is the Canadian government's national cryptologic agency. Administered under the Department of National Defence , it is charged with the duty of keeping track of foreign signals intelligence , and protecting Canadian government electronic...
  
   (CSE) – Canadian intelligence agency

Open efforts

• DES
  Data Encryption Standard
  The Data Encryption Standard is a block cipher that uses shared secret encryption. It was selected by the National Bureau of Standards as an official Federal Information Processing Standard for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is...
  
   – NBS selection process, ended 1976
• RIPE – division of the RACE project sponsored by the European Union
  European Union
  The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
  
  , ended mid-'80s
• AES
  Advanced Encryption Standard
  Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...
  
   – a "break-off" competition sponsored by NIST, ended in 2001
• NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
   Project – an evaluation/selection program sponsored by the European Union
  European Union
  The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
  
  , ended in 2002
• eSTREAM
  ESTREAM
  eSTREAM is a project to "identify new stream ciphers suitable for widespread adoption", organised by the EU ECRYPT network. It was set up as a result of the failure of all six stream ciphers submitted to the NESSIE project. The call for primitives was first issued in November 2004. The project was...
  
  – program funded by ECRYPT
  ECRYPT
  ECRYPT is a 4-year European research initiative launched on 1 February 2004.The stated objective is to, "intensify the collaboration of European researchers in information security, and more in particular in cryptology and digital watermarking.ECRYPT list five core research areas, termed "virtual...
  
  ; motivated by the failure of all of the stream cipher
  Stream cipher
  In cryptography, a stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream . In a stream cipher the plaintext digits are encrypted one at a time, and the transformation of successive digits varies during the encryption...
  
  s submitted to NESSIE
  NESSIE
  NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...
  
  , ended in 2008
• CRYPTREC
  CRYPTREC
  CRYPTREC is the Cryptography Research and Evaluation Committees set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use...
  
   – evaluation/recommendation program sponsored by the Japanese government; draft recommendations published 2003
• Internet Engineering Task Force – technical body responsible for Internet standards— the Request for Comment
  Request for Comments
  In computer network engineering, a Request for Comments is a memorandum published by the Internet Engineering Task Force describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.Through the Internet Society, engineers and...
  
   series is ongoing
• CrypTool
  Cryptool
  CrypTool is an open source e-learning tool illustrating cryptographic concepts.-Features:The graphical interface, online documentation, analytic tools and algorithms of CrypTool introduce users to the field of cryptography...
  
   – an e-learning freeware programme in English and German— exhaustive educational tool about cryptography and cryptanalysis

Legal issues

• Free speech
• Bernstein v. United States
  Bernstein v. United States
  Bernstein v. United States is a set of court cases brought by Daniel J. Bernstein challenging restrictions on the export of cryptography from the United States....
  
  –
• Junger v. Daley
  Junger v. Daley
  Junger v. Daley is a court case brought by Peter Junger challenging restrictions on the export of encryption software outside of the United States....
  
  –
• DeCSS
  DeCSS
  DeCSS is a computer program capable of decrypting content on a commercially produced DVD video disc. Before the release of DeCSS, there was no way for computers running a Linux-based operating system to play video DVDs....
  
   –
• Phil Zimmermann
  Phil Zimmermann
  Philip R. "Phil" Zimmermann Jr. is the creator of Pretty Good Privacy , the most widely used email encryption software in the world. He is also known for his work in VoIP encryption protocols, notably ZRTP and Zfone....
  
   –
• Export of cryptography
  Export of cryptography
  The export of cryptography in the United States is the transfer from the United States to another country of devices and technology related to cryptography....
  
   –
• Key escrow
  Key escrow
  Key escrow is an arrangement in which the keys needed to decrypt encrypted data are held in escrow so that, under certain circumstances, an authorized third party may gain access to those keys...
  
   and Clipper Chip
  Clipper chip
  The Clipper chip was a chipset that was developed and promoted by the U.S. National Security Agency as an encryption device to be adopted by telecommunications companies for voice transmission...
  
   –
• Digital Millennium Copyright Act
  Digital Millennium Copyright Act
  The Digital Millennium Copyright Act is a United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization . It criminalizes production and dissemination of technology, devices, or services intended to circumvent measures that control access to...
  
   –
• Digital Rights Management
  Digital rights management
  Digital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
  
   (DRM) –
• Patents
• RSA – now public domain
• David Chaum
  David Chaum
  David Chaum is the inventor of many cryptographic protocols, including blind signature schemes, commitment schemes, and digital cash. In 1982, Chaum founded the International Association for Cryptologic Research , which currently organizes academic conferences in cryptography research...
  
   – and digital cash
• Cryptography and law enforcement
• Wiretaps
  Telephone tapping
  Telephone tapping is the monitoring of telephone and Internet conversations by a third party, often by covert means. The wire tap received its name because, historically, the monitoring connection was an actual electrical tap on the telephone line...
  
   –
• Espionage
  Espionage
  Espionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, lest the legitimate holder of the information change plans or take other countermeasures once it...
  
   –
• Cryptography laws in different nations
  Cryptography laws in different nations
  Cryptography is the practice and study of hiding information. There are many different cryptography laws in different nations. Some countries prohibit export of cryptography software and/or encryption algorithms or cryptoanalysis methods. In some countries a license is required to use encryption...
  
  
• Official Secrets Act
  Official Secrets Act
  The Official Secrets Act is a stock short title used in the United Kingdom, Ireland, India and Malaysia and formerly in New Zealand for legislation that provides for the protection of state secrets and official information, mainly related to national security.-United Kingdom:*The Official Secrets...
  
   – United Kingdom
  United Kingdom
  The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
  
  , India
  India
  India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
  
  , Ireland
  Ireland
  Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
  
  , Malaysia, and formerly New Zealand
  New Zealand
  New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
  
  
• Regulation of Investigatory Powers Act 2000
  Regulation of Investigatory Powers Act 2000
  The Regulation of Investigatory Powers Act 2000 is an Act of the Parliament of the United Kingdom, regulating the powers of public bodies to carry out surveillance and investigation, and covering the interception of communications...
  
   – United Kingdom
  United Kingdom
  The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
  
  

Academic and professional publications

Further information: Important publications in cryptography & Books on cryptography

Books on cryptography

Books on cryptography have been published sporadically and with highly variable quality for a long time. This is despite the tempting, though superficial, paradox that secrecy is of the essence in sending confidential messages — see Kerckhoffs' principle....

• Journal of Cryptology
  Journal of Cryptology
  The Journal of Cryptology is a scientific journal in the field of cryptology and cryptography. The journal is published quarterly by the International Association for Cryptologic Research....
  
   –
• Encyclopedia of Cryptography and Security
  Encyclopedia of Cryptography and Security
  The Encyclopedia of Cryptography and Security is a comprehensive work on Cryptography for both information security professionals and experts in the fields of Computer Science, Applied Mathematics, Engineering, Information Theory, Data Encryption, etc . It consists of 460 articles in alphabetical...
  
   –
• Cryptologia
  Cryptologia
  Cryptologia is a journal in cryptography published quarterly since January 1977. Its remit is all aspects of cryptography, but there is a special emphasis on historical aspects of the subject. The founding editors were Brian J. Winkel, David Kahn, Louis Kruh, Cipher A. Deavours and Greg Mellen...
  
   – quarterly journal focusing on historical aspects
• Communication Theory of Secrecy Systems
  Communication Theory of Secrecy Systems
  Communication Theory of Secrecy Systems is a paper published in 1949 by Claude Shannon discussing cryptography from the viewpoint of information theory. It is one of the foundational treatments of modern cryptography...
  
   – cryptography from the viewpoint of information theory

See also

• Cypherpunk
  Cypherpunk
  A cypherpunk is an activist advocating widespread use of strong cryptography as a route to social and political change.Originally communicating through the Cypherpunks electronic mailing list, informal groups aimed to achieve privacy and security through proactive use of cryptography...
  
   –
• Crypto-anarchism
  Crypto-anarchism
  Crypto-anarchism expounds the use of strong public-key cryptography to bring about privacy and freedom. It was described by Vernor Vinge as a cyberspatial realization of anarchism. Crypto-anarchists aim to create cryptographic software that can be used to evade prosecution and harassment while...
  
   –
• Echelon –
• Zodiac Killer
  Zodiac Killer
  The Zodiac Killer was a serial killer who operated in Northern California in the late 1960s and early 1970s. The killer's identity remains unknown. The Zodiac murdered victims in Benicia, Vallejo, Lake Berryessa and San Francisco between December 1968 and October 1969. Four men and three women...
  
  –

External links