Cryptography Flashcards
What are different type of ciphers?
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Tell something about block cipher
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Tell something about stream cipher
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How many bits of data is there in DES and how many bits of key is there?
64 bits data and 56 bit key, block
unclassified material of US government agencies
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What type of algorithm does AES use
symetric key, iterated block chiper
Block size and key size of AES ?
128 bit block, 128, 192 and 256
RC4
variable key size symetric key stream chiper with byte oriented operations and is based on use of random permutation
RC5
Parametric algorithm with variable block size, variable key size and a variable number of rounds the key size is 128 bits
RC6
Symmetric key block cipher derived from RC5 with two additional features: uses integer multiplication, four 4-bit working registers RC5 uses 2 2-bit
Twofish
Final list to replace DES for government but was not chosen
block size of 128 key size upto 256 bit
Feistel cipher
Feistel cipher
two fish
DSA
FIPS 186-2 specifies generation in verification of digital signature
RSA
Rivest, Shamir, Adleman
which is the defacto encryption standard ?
RSA. Modular and elementary number theories to perform useinf two large integers
Diffie- Hellman
1) a cryptographic protocol that allows two parties to establish a shared key over an insecure channel
2) whitefield Diffie and Martin Hellman in 1976
3) Malcolm J Williamson of british intelligence service but it was classified
two parameters p and g
Diffie Hellman
Message Digest
Calculate unique fix size bit string
If any given bit of functions input is changed then every output bit has a 50% chance of changing
It is computationally in feasible to have two files with same message digest values