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SHA-512 Overall Structure

The document summarizes the SHA-512 algorithm used for cryptographic hashing. It describes the overall structure including message preparation by padding and adding a length field. It explains how the processing block and its digest are handled as words that undergo word expansion. It provides details on the SHA-512 compression function including how it uses constants that vary each round. The structure of each round is outlined showing how values are calculated and passed to the next round. Initial buffer register values and constants used over 80 rounds are also listed.

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RAMI RAMI
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70 views5 pages

SHA-512 Overall Structure

The document summarizes the SHA-512 algorithm used for cryptographic hashing. It describes the overall structure including message preparation by padding and adding a length field. It explains how the processing block and its digest are handled as words that undergo word expansion. It provides details on the SHA-512 compression function including how it uses constants that vary each round. The structure of each round is outlined showing how values are calculated and passed to the next round. Initial buffer register values and constants used over 80 rounds are also listed.

Uploaded by

RAMI RAMI
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Mustansiriyah University Class: Third Year

Faculty of Engineering Cryptographic Hash Functions Course name: Data Security


Computer Engineering Dep. SHA-512 Algorithm Lecturer: Fatimah Al-Ubaidy
SHA-512 Overall Structure

Message Preparation (padding and length field):

• The length of the padding field can be calculated as


(|M| + |P| + 128) = 0 mod 1024 → |P| = (− |M| − 128) mod 1024
Where |M| is the length of original message and |P| the length of the padding field. 1
Mustansiriyah University Class: Third Year
Faculty of Engineering Cryptographic Hash Functions Course name: Data Security
Computer Engineering Dep. SHA-512 Algorithm Lecturer: Fatimah Al-Ubaidy
Processing block and its digest as word

Word Expansion:

Wi is the processing word of the current round i 2


Mustansiriyah University Class: Third Year
Faculty of Engineering Cryptographic Hash Functions Course name: Data Security
Computer Engineering Dep. SHA-512 Algorithm Lecturer: Fatimah Al-Ubaidy
SHA-512 Compression Function:

Ki is a constant
variable at round i
where i =0,1…79.

3
Mustansiriyah University Class: Third Year
Faculty of Engineering Cryptographic Hash Functions Course name: Data Security
Computer Engineering Dep. SHA-512 Algorithm Lecturer: Fatimah Al-Ubaidy
Structure of each round in SHA-512:

A = T1 + T 2
B=A
C=B
D=C
E = D + T1
F=E T2 T1
G=F
H=G
T1 = H + conditional(E,F,G) +
rotate(E) + Wi + Ki
T2 = majority(A,B,C) +
rotate(A)

4
Mustansiriyah University Class: Third Year
Faculty of Engineering Cryptographic Hash Functions Course name: Data Security
Computer Engineering Dep. SHA-512 Algorithm Lecturer: Fatimah Al-Ubaidy
The initial values of the buffer registers as 64-bit each
a = 6A09E667F3BCC908 e = 510E527FADE682D1
b = BB67AE8584CAA73B f = 9B05688C2B3E6C1F
c = 3C6EF372FE94F82B g = 1F83D9ABFB41BD6B
d = A54FF53A5F1D36F1 h = 5BE0CD19137E2179

Eighty constants used for the eighty rounds in the SHA-512

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