Hash and MAC Algorithms. MD5 in detail Overview of SHA and RIPEMD-160 HMAC. Introduction. There is a general structure used practically in all cryptanalytically srtong hash-function fig. 8.10 analogous to the Feistel cipher as a general structure of block-ciphers
MD5 in detail
Overview of SHA and RIPEMD-160
CV0 = IV
CVq+1= SUM32(CVq, RFI[Yq, RFH[Yq, RFG[Yq, RFF[Yq, CVq]]]] )
MD = CVL.
IV = initial value of the ABCD buffer
Yq = the qth 512-block of the message.
L = the number of blocks
CVq= chaining variable processed with the the qth block of the message
RFX= round function using primitive logical function X
MD = final message digest value
SUM32= Addition module 232 performed separatedly on each pair of words of the two inputs.
a b + (( a + g(b,c,d) + X[k] + T[i] ) <<< s )
a,b,c,d = the four words of the buffer, in a specified order that varies from step to step
g = one of the primitive functions F, G, H, I
<<< s = circular left shift (rotation) of the 32-bit argument by s bits.
X[k] = M[q 16 k] = the kth 32-bit word in the qth 512-bit block of the message
T[i] = the ith 32-bit word in matrix T
+ = addition modulo 232.
HMACK = H[(K+ opad) || H[(K+ ipad) || M ]]