2 Comments on “All of the following are valid cryptographic hash functions EXCEPT:”

1. R says:

   August 4, 2013 at 8:56 pm

   B rc4

   
   
   
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2. meac says:

   June 7, 2018 at 5:41 pm

   It is a 50/50 for me…I know for certain that C & D are correct, as I created plenty of hashes with them.

   VALID CRYPTOGRAPHIC HASH FUNCTIONS
   A- RIPEMD (RACE Integrity Primitives Evaluation Message Digest) is a family of cryptographic hash functions developed in Leuven, Belgium, by Hans Dobbertin, Antoon Bosselaers and Bart Preneel at the COSIC research group at the Katholieke Universiteit Leuven, and first published in 1996.
   C-SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA).. They are built using the Merkle–Damgård structure, from a One-way compression function itself built using the Davies-Meyer structure from a (classified) specialized block cipher.
   D-The MD4 Message-Digest Algorithm is a cryptographic hash function developed by Ronald Rivest in 1990. The digest length is 128 bits. The algorithm has influenced later designs, such as the MD5, SHA-1 and RIPEMD algorithms. The initialism “MD” stands for “Message Digest.”

   So the answer is: B-RC4
   B- In cryptography, RC4 (Rivest Cipher 4 also known as ARC4 or ARCFOUR meaning Alleged RC4, see below) is a STREAM CIPHER. While remarkable for its simplicity and speed in software, multiple vulnerabilities have been discovered in RC4, rendering it insecure.It is especially vulnerable when the beginning of the output keystream is not discarded, or when nonrandom or related keys are used. Particularly problematic uses of RC4 have led to very insecure protocols such as WEP.
   So RC4 is not a hash function. RC4 is popular STREAM CIPHER with wireless and WEP/WPA encryption.

   
   
   
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