Advanced Encryption Standard: Difference between revisions
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The '''Advanced Encryption Standard''', or '''AES''', is a US government specification for a [[block cipher]] to replace earlier and weaker [[Data Encryption Standard]]. | The '''Advanced Encryption Standard''', or '''AES''', is a US government specification for a [[block cipher]] to replace the earlier and weaker [[Data Encryption Standard]] (DES). | ||
AES encrypts data in 128-bit blocks and can take a 128, 192 or 256-bit key. DES used 64-bit blocks and a 56-bit key. | |||
Starting in the late 90s, the US [[National Institute of Standards and Technology]] (NIST) ran a [[AES contest |contest]] to find a block cipher to replace DES. The result is the Advanced Encryption Standard. In October 2002, they announced [http://www.nist.gov/public_affairs/releases/g00-176.htm] the winner — '''Rijndael''' (pronounced approximately "rhine doll"), from two Belgian designers. | Starting in the late 90s, the US [[National Institute of Standards and Technology]] (NIST) ran a [[AES contest |contest]] to find a block cipher to replace DES. The result is the Advanced Encryption Standard. In October 2002, they announced [http://www.nist.gov/public_affairs/releases/g00-176.htm] the winner — '''Rijndael''' (pronounced approximately "rhine doll"), from two Belgian designers. | ||
The NIST page on AES [http://csrc.nist.gov/archive/aes/rijndael/wsdindex.html] has much detail, including links to all the Rinjdael design documents, to several implementations, and to the official standard, approved as FIPS 197, | The NIST page on AES [http://csrc.nist.gov/archive/aes/rijndael/wsdindex.html] has much detail, including links to all the Rinjdael design documents, to several implementations, and to the official standard, approved as FIPS 197, | ||
Because of the [[birthday attack]], a [[hash algorithm]] needs to provide output of 2n bits to resist attacks as well as a cipher with an n-bit key. NIST has therefore issued standards for the [[SHA-2]] family of hashes — SHA-256, SHA-384 and SHA-512 to match the strength of AES, plus SHA-224 to match the 112-bit strength of [[Triple DES]]. However, those hashes are all derived from [[SHA]] and some weaknesses (minor so far) have been shown in that, so in 2008 NIST started a contest similar to the AES contest to design an [[Advanced Hash Standard]] which can (if it proves necessary) replace SHA-2 as AES replaced DES. | |||
==References== | ==References== | ||
{{reflist|2}} | {{reflist|2}} | ||
Revision as of 03:08, 26 October 2008
Template:TOC-right The Advanced Encryption Standard, or AES, is a US government specification for a block cipher to replace the earlier and weaker Data Encryption Standard (DES).
AES encrypts data in 128-bit blocks and can take a 128, 192 or 256-bit key. DES used 64-bit blocks and a 56-bit key.
Starting in the late 90s, the US National Institute of Standards and Technology (NIST) ran a contest to find a block cipher to replace DES. The result is the Advanced Encryption Standard. In October 2002, they announced [1] the winner — Rijndael (pronounced approximately "rhine doll"), from two Belgian designers.
The NIST page on AES [2] has much detail, including links to all the Rinjdael design documents, to several implementations, and to the official standard, approved as FIPS 197,
Because of the birthday attack, a hash algorithm needs to provide output of 2n bits to resist attacks as well as a cipher with an n-bit key. NIST has therefore issued standards for the SHA-2 family of hashes — SHA-256, SHA-384 and SHA-512 to match the strength of AES, plus SHA-224 to match the 112-bit strength of Triple DES. However, those hashes are all derived from SHA and some weaknesses (minor so far) have been shown in that, so in 2008 NIST started a contest similar to the AES contest to design an Advanced Hash Standard which can (if it proves necessary) replace SHA-2 as AES replaced DES.