Notation

C

Cipher text block

DK()

Decryption algorithm using encryption/decryption key K

EK()

Encryption algorithm using encryption/decryption key K

H()

Hash function

i

Block index for n-bit blocks; n is context-dependent

K

Cryptographic key

P

Plaintext block

^

Bitwise exclusive-OR operation (XOR)

Addition

Modulo 2n addition, where n is the bit size of the left-most operand and of the resultant value (e.g., if the left operand is a 1-bit value, and the right operand is a 2-bit value, then: 1 Addition 0 = 1; 1 Addition 1 = 0; 1 Addition 2 = 1; 1 Addition 3 = 0; 0 Addition 0 = 0; 0 Addition 1 = 1; 0 Addition 2 = 0; 0 Addition 3 = 1)

Multiplication

Modular multiplication of two polynomials over the binary field GF(2), modulo x128+x7+x2+x+1 (GF stands for Galois Field)

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Concatenation