AS2
Encyclopedia
AS2 is a specification about how to transport data securely and reliably over the Internet
. Security is achieved by using digital certificates and encryption
.
. It was the second AS protocol developed and uses the same signing, encryption and MDN (as defined by RFC3798) conventions used in the original AS1
protocol. In other words:
Like any other AS file transfer, AS2 file transfers typically require both sides of the exchange to trade SSL certificates and specific "trading partner" names before any transfers can take place. AS2 trading partner names can usually be any valid phrase.
file transfers, AS2 file transfers offer several "MDN return" options instead of the traditional options of "yes" or "no". Specifically, the choices are:
situations).
rather than HTTP. Otherwise, it is similar to "AS2 Async (HTTP)".
There are two profiles for filename preservation being optionally tested under AS2 testing:
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
. Security is achieved by using digital certificates and 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...
.
AS2 Technical Overview
The AS2 protocol is based on HTTP and S/MIMES/MIME
S/MIME is a standard for public key encryption and signing of MIME data. S/MIME is on an IETF standards track and defined in a number of documents, most importantly RFCs. S/MIME was originally developed by RSA Data Security Inc...
. It was the second AS protocol developed and uses the same signing, encryption and MDN (as defined by RFC3798) conventions used in the original AS1
AS1 (networking)
AS1 is a specification about how to transport data securely and reliably over the Internet. Security is achieved by using digital certificates and encryption.- AS1 Technical Overview :...
protocol. In other words:
- Files are encoded as "attachments" in a standardized S/MIMES/MIMES/MIME is a standard for public key encryption and signing of MIME data. S/MIME is on an IETF standards track and defined in a number of documents, most importantly RFCs. S/MIME was originally developed by RSA Data Security Inc...
message (an AS2 message). - AS2 messages are always sent using the HTTP or HTTPSHttpsHypertext Transfer Protocol Secure is a combination of the Hypertext Transfer Protocol with SSL/TLS protocol to provide encrypted communication and secure identification of a network web server...
protocol (Secure Sockets Layer — also known as SSL — is implied by HTTPS) and usually use the "POST" method (use of "GET" is rare). - Messages can be signed, but do not have to be.
- Messages can be encrypted, but do not have to be.
- Messages may request a Message Disposition Notification [MDN] back if all went well, but do not have to request such a message.
- If the original AS2 message requested an MDN:
- Upon the receipt of the message and its successful decryption or signature validation (as necessary) a "success" MDN will be sent back to the original sender. This MDN is typically signed but never encrypted (unless temporarily encrypted in transit via HTTPS).
- Upon the receipt and successful verification of the signature on the MDN, the original sender will "know" that the recipient got their message (this provides the "Non-repudiation" element of AS2)
- If there are any problems receiving or interpreting the original AS2 message, a "failed" MDN may be sent back. However, part of the AS2 protocol states that the client must treat a lack of an MDN as a failure as well, so some AS2 receivers will simply not return an MDN in this case.
- Upon the receipt of the message and its successful decryption or signature validation (as necessary) a "success" MDN will be sent back to the original sender. This MDN is typically signed but never encrypted (unless temporarily encrypted in transit via HTTPS).
Like any other AS file transfer, AS2 file transfers typically require both sides of the exchange to trade SSL certificates and specific "trading partner" names before any transfers can take place. AS2 trading partner names can usually be any valid phrase.
MDN Options
Unlike AS1 or AS3AS3 (networking)
AS3 is the draft specification standard by which vendor applications communicate EDI over the Internet using File Transfer Protocol ....
file transfers, AS2 file transfers offer several "MDN return" options instead of the traditional options of "yes" or "no". Specifically, the choices are:
AS2 w/ "Sync" MDNs
Return Synchronous MDN via HTTP(S) ("AS2 Sync") - This popular option allows AS2 MDNs to be returned to AS2 message sender clients over the same HTTP connection they used to send the original message. This "MDN while you wait" capability makes "AS2 Sync" transfers the fastest of any type of AS file transfer, but it also keeps this flavor of MDN request from being used with large files (which may time out in low-bandwidthBandwidth (computing)
In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...
situations).
AS2 w/ "ASync" MDNs
Return Asynchronous MDN via HTTP(S) (a.k.a. "AS2 Async") - This popular option allows AS2 MDNs to be returned to the AS2 message sender's server later over a different HTTP connection. This flavor of MDN request is usually used if large files are involved or if your trading partner's AS2 server has poor Internet service.AS2 w/ "Email" MDNs
Return (Asynchronous) MDN via Email - This rarely-used option allows AS2 MDNs to be returned to AS2 message senders via emailEmail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
rather than HTTP. Otherwise, it is similar to "AS2 Async (HTTP)".
AS2 w/ No MDNs
Do not return MDN - This option works like it does in any other AS protocol: the receiver of an AS2 message with this option set simply does not try to return an MDN to the AS2 message sender.AS2 FileName Preserve
AS2 filename preservation feature will be used to communicate the filename to the trading partner. The banking industry relies on filenames being communicated between trading partners. AS2 vendors are currently certifying that implementation of filename communication conforms to the standard and is interoperable.There are two profiles for filename preservation being optionally tested under AS2 testing:
- Filename preservation without MDN responses
- Filename preservation with an associated MDN response certification
External links
- AS2 Specification, RFC 4130 AS2 specification as listed in RFCRequest for CommentsIn 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...
#4130 - AS2 secures documents using the Web
- AS2 Providers - Drummond Certified
- Opensource AS2 Providers
- UltraESB, an Open Source Enterprise Service Bus (ESB) that supports AS2 along with other enterprise integration
- BabelAS2, a very simple VBScript to send any message using AS2, just to demonstrate that AS2 is NOT difficult/complex ;-)
- AS2Secure Php Lib implementation - Opensource Project available under LGPL v3
- AS2 Basics Resource for learning about AS2 and how to trade electronically with your partners
- AS2Box Managed AS2 Service