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
MD5
Arbitrary length, 128 bit fingerprint.
Not collision resistant, better use SHA-two and SHA-three
SHA - 1
full form, SHA-1 160-bit digest, (264-1) bits, resembles MD5
SHA-2
It is a family of two similar hash functions with different block sizes. SHA 256 that uses 32 bit words and SHA 512 that uses 64-bit words.
SHA-3
Uses sponge construction in which message blocks are XORED into the initial bits of the state which is then invertiblely permuted.
RIPMD-160
RACE integrity primitives evaluation message digest 160-bit hash algorithm
128,256,320 variants there.
-> 80 stages madeup of 5 blocks that execute 16 times each
repeats twice
HMAC full form and from which types of attacks it protects ?
message authentication code, length extension attacks
Whats PKI and whats it used for ?
Public key infrastructure is a security architecture develop to increase the confidentiality of information exchanged over the insecure internet. It includes hardware software people policies and procedures required to create manage distribute use store and revoke digital certificates in cryptography the PKI helps to bind public keys with corresponding user identities by means of certificate authority
Components of PKI
Certificate management system
Digital certificates
Validation authority VA
Certificate Authority CA
End user
Registration authority RA
difference between signed certificate vs self signed certificate
CA, public key VA etc. invilbed in sign certificate.
Self signed its private key exchange.
Digital Signature
Digital signature use uses a symmetric crypto Graffi to simulate the security properties of a signature in digital rather than written form
SIGN->SEAL-DELIVER ACCEPT->OPEN-VERIFY
SSL
SSL is an application layer protocol developed by Netscape for managing the security of a message transmission on the internet
It uses RSA asymmetric encryption to encrypt data transfer over SSL connections
TLS
CryptaAnalysis Methods
Code breaking methodologies
Cryptography attacks
Cryptography attacks (cont’d)
Brute force attack
Birthday Attack
Side Channel Attack
Hash Collision Attack
DUHK attack
Rainbow table attack
cryptanalysis tools
dds
how to defend against cryptographic attacks
Digital certificates -> master sheet
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full disk encryption -> MS
…
Heartbleed, freak, poodle and drown -> MS
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