Thursday, November 20, 2008

Why SHA-3 Doesn't Matter Sense

First, lets look at a little encryption history...

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Data Encryption Standard

Lucifer was the name given to several of the earliest civilian block ciphers, developed by Horst Feistel and his colleagues at IBM.

IBM submitted the Feistel-network version of Lucifer as a candidate for DES. IBM, with the help the NSA, tweaked the original design (a reduction to a 56-bit key and 64-bit block, but strengthened against differential cryptanalysis). This tweaked version became the Data Encryption Standard in 1977.

Advanced Encryption Standard

On January 2, 1997, NIST announced that they wished to choose a successor to DES to be known as Advanced Encryption Standard (AES). After evaluating fifteen competing designs as part of a 5-year standardization process, Rijndael (with a fixed block size of 128-bit) was selected as the most suitable algorithm....and assigned the new name of AES.

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Now to the cryptographic hash algorithms......

Secure Hash Algorithm 1 & 2

A cryptographic hash algorithm converts a variable length message into a short “message digest” that can be used for digital signatures, message authentication and other applications.

The SHA hash functions are a set of cryptographic hash functions designed by the National Security Agency (NSA) and published by the NIST as a U.S. Federal Information Processing Standard. SHA stands for Secure Hash Algorithm. The three SHA algorithms are structured differently and are distinguished as SHA-0,SHA-1, and SHA-2. The SHA-2 family uses an identical algorithm with a variable key size which is distinguished as SHA-224, SHA-256, SHA-384, and SHA-512.

In 2005, security flaws were identified in SHA-1, namely that a possible mathematical weakness might exist, indicating that a stronger hash function would be desirable. Although no attacks have yet been reported on the SHA-2 variants, they are algorithmically similar to SHA-1 and so efforts are underway to develop improved alternatives. A new hash function, to be known as SHA-3, is currently under development, to be selected via open competition starting in 2008, and to be made official in 2012.

Secure Hash Algorithm 3

Building on the success of the AES competition, NIST has opened a public competition to develop a new cryptographic hash algorithm. The competition is NIST’s response to recent advances in the cryptanalysis of hash functions. The new hash algorithm will be called “SHA-3” and will augment the hash algorithms currently specified in FIPS 180-2, Secure Hash Standard.

According to SHA-3 Zoo, 29 out of 64 submissions to the SHA-3 competition are publicly known and available, and hence take advantage of early external cryptanalysis (so far, 6 submissions have been broken).

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Since both AES and SHA-3 will be the result of a public competition. The algorithm selected as SHA-3, will most likely not be related to the hashes in the SHA family...so why not call it "Advanced Hash Standard" (AHS)?

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