Iraqi block cipher
Encyclopedia
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
.
A comment
suggests that it is of Iraq
i origin. However, like the S-1 block cipher, it is generally regarded as a hoax
, although of lesser quality than S-1. Although the comment suggests that it is Iraqi in origin, all comments, variable and function names and printed string
s are in English rather than Arabic; the code is fairly inefficient (including some pointless operations), and the cipher's security may be flawed (no proof).
Because it has a constant key schedule
the cipher is vulnerable to a slide attack
. However, it may take 264 chosen texts to create a single slid pair, which would make the attack unfeasible. It also has a large number of fixed point
s, although that is not
necessarily a problem, except possibly for hashing modes. No public attack is currently available. As with S-1, it was David Wagner who first spotted the security flaws.
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...
, the Iraqi block cipher was a block cipher
Block cipher
In cryptography, a block cipher is a symmetric key cipher operating on fixed-length groups of bits, called blocks, with an unvarying transformation. A block cipher encryption algorithm might take a 128-bit block of plaintext as input, and output a corresponding 128-bit block of ciphertext...
published in C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
source code
Source code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
form by anonymous FTP upload around July 1999, and widely distributed on Usenet
Usenet
Usenet is a worldwide distributed Internet discussion system. It developed from the general purpose UUCP architecture of the same name.Duke University graduate students Tom Truscott and Jim Ellis conceived the idea in 1979 and it was established in 1980...
. It is a five round unbalanced 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...
operating on a 256 bit block
Block size (cryptography)
In modern cryptography, symmetric key ciphers are generally divided into stream ciphers and block ciphers. Block ciphers operate on a fixed length string of bits. The length of this bit string is the block size...
with a 160 bit key
Key size
In cryptography, key size or key length is the size measured in bits of the key used in a cryptographic algorithm . An algorithm's key length is distinct from its cryptographic security, which is a logarithmic measure of the fastest known computational attack on the algorithm, also measured in bits...
.
A comment
Comment
A comment is generally a verbal or written remark often related to an added piece of information, or an observation or statement. These are usually marked with an abbreviation, such as "obs." or "N.B."...
suggests that it is of Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
i origin. However, like the S-1 block cipher, it is generally regarded as a hoax
Hoax
A hoax is a deliberately fabricated falsehood made to masquerade as truth. It is distinguishable from errors in observation or judgment, or rumors, urban legends, pseudosciences or April Fools' Day events that are passed along in good faith by believers or as jokes.-Definition:The British...
, although of lesser quality than S-1. Although the comment suggests that it is Iraqi in origin, all comments, variable and function names and printed string
String (computer science)
In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....
s are in English rather than Arabic; the code is fairly inefficient (including some pointless operations), and the cipher's security may be flawed (no proof).
Because it has a constant key schedule
Key schedule
[[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES [[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES [[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES ("[[Image:DES-key-schedule.png|thumbnail|220px|The key schedule of DES ("...
the cipher is vulnerable to a 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...
. However, it may take 264 chosen texts to create a single slid pair, which would make the attack unfeasible. It also has a large number of fixed point
Fixed point (mathematics)
In mathematics, a fixed point of a function is a point that is mapped to itself by the function. A set of fixed points is sometimes called a fixed set...
s, although that is not
necessarily a problem, except possibly for hashing modes. No public attack is currently available. As with S-1, it was David Wagner who first spotted the security flaws.