6-3 Flashcards
binary encryption does not work well for secure communications sinc ethe underlying _________ and _________ frequency remains
letter and word
the following websites offer more information about cryptography
coursera, udacity, cipher research labratories
this refers to the method where the same key is used to encrypt and decrypt the plain text
Symetric encryption
developed by ibm in the early 70s, and made public in 1976.uses symetric key system. uses short keys and relies on complex procedures to secure information.
DES
the des algorithim is compluicated, data is divided into ___blocks. transposed by 16 rounds of encryption using a___ bit key
64 // 56
des is a ______ with 16 rounds and a 48 bit round key for each round
feistel
to generate the round keys the ___ bit key is split into 2 ___ bit halves and those halves are circularly shifted after each round by one or __ bits
56 // 28 // 2
__________ a symmetric bloc cipher. that means a single key is used to encrypt and decrypt the message and works in blocks. it uses an average key length from 32 to 448 bitsdesigned in 1993 by bruce scheier. free of charge product
blowfish
______operates on blocks of fixed length. normally 64 or 128 bit length. its applied to a block of data
block cipher
takes the text as an outgoing stream. encrypting each bit as it encounters it. tend to be faster then block ciphers. generates a keystream
stream cipher
uses the rijndael algorithm. developed by 2 belgina researcherso joan daemon and vincent rijmen. 3 specific key sizes___, ___, ___. it uses a block cipher. widely used
AES
128 // 192 // 256
AES algorithim uses a few relativly simple steps
AddRoundKey
SubBytes
ShiftRows
MixColumns
eachbit of the state is combined with the round key using bitwise XOR
ADDRoundKey
a non linear substituation step where each byte is replaced with another according to a lookup table
SubBytes
a transposition step where each row of the state is shifted cyclically a certain number of steps
ShiftRow
