Cryptography 10 Flashcards
a known plaintext attack and uses a linear approximation to describe the behavior of the block cipher. Given sufficient pairs of plaintext and corresponding ciphertext, bits of information about the key can be obtained and increased amounts of data will usually give a higher probability of success.
Linear Cryptanalaysis
a form of cryptanalysis applicable to symmetric key algorithms. This was invented by Eli Biham and Adi Shamir. The examination of differences in an input and how that affects the resultant difference in the output.
Differential Cryptanalysis
Similar to Differential Cryptanalysis, but uses a different technique. Uses sets or even multisets of chosen plaintexts of which part is held constant and another part varies through all possibilities.
Integral Cryptanalysis
??? attacker discovers a functionally equivalent algorithm for encryption and decryption, but without learning the key.
??? attacker gains some information about plaintexts (or ciphertexts) not previously known.
??? attacker discovers additional plaintexts (or ciphertexts) not previously known.
*** Total break - attacker gets the key.
Global deduction / Information deduction / Instance (local) deduction Etc …
Distinguishing algorithm - attacker can distinguish the cipher from a random permutation.
3 Resources to perform Cryptanalysis : time, memory, data
Co-Prime Numbers: a number that has no factors in common with another number ( 3 & 7 )
Eulers Totient: counts the positive integers up to a given integer n that are relatively prime to n.
For example, 7 has six numbers that are co-prime to it.
info #6 …
1st - 1100
2nd - 0100
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Result - 0100
Binary AND
** (1 + 0 = 0), (1 + 1 = 1), (0 + 0 = 0) **
1st - 1010
2nd - 0100
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Result - 1110
Binary OR
*** (1 + 0 = 1), (0 + 1 = 1), (0 + 0 = 0)
1st 1110
2nd 0101
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Result - 1011
Binary XOR
** (1 + 0 = 1), (1 + 1 = 0), (0 + 1 = 1) **
