Snefru is a cryptographic hash function

Cryptographic hash function

A cryptographic hash function is a deterministic procedure that takes an arbitrary block of data and returns a fixed-size bit string, the hash value, such that an accidental or intentional change to the data will change the hash value...

 invented by Ralph Merkle

Ralph Merkle

Ralph C. Merkle is a researcher in public key cryptography, and more recently a researcher and speaker on molecular nanotechnology and cryonics...

in 1990
which supports 128-bit and 256-bit output. It was named after the Egyptian

Ancient Egypt

Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...

 Pharaoh

Pharaoh

Pharaoh is a title used in many modern discussions of the ancient Egyptian rulers of all periods. The title originates in the term "pr-aa" which means "great house" and describes the royal palace...

 Sneferu

Sneferu

Sneferu, also spelled as Snephru, Snefru or Snofru , was the founder of the Fourth dynasty of Egypt. Estimates of his reign vary, with for instance The Oxford History of Ancient Egypt suggesting a reign from around 2613 BC to 2589 BC, a reign of 24 years, while Rolf Krauss suggests a 30-year reign...

, continuing the tradition of the Khufu and Khafre 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...

s.

The original design of Snefru was shown to be insecure by 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...

 and Adi Shamir

Adi Shamir

Adi Shamir is an Israeli cryptographer. He is a co-inventor of the RSA algorithm , a co-inventor of the Feige–Fiat–Shamir identification scheme , one of the inventors of differential cryptanalysis and has made numerous contributions to the fields of cryptography and computer...

 who were able to use differential cryptanalysis

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...

 to find hash collisions. The design was then modified by increasing the number of iterations of the main pass of the algorithm from two to eight. Although differential cryptanalysis can break the revised version with less complexity than brute force search

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...

 (a certificational weakness), the attack requires operations and is thus not currently feasible in practice.

External links

• Ecrypt page
• RHash, an open source
  Open source
  The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
  
  command-line tool, which can calculate and verify Snefru-128 and Snefru-256