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
^
Bitwise exclusive-OR operation (XOR)
⊕
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 ⊕ 0 = 1; 1 ⊕ 1 = 0; 1 ⊕ 2 = 1; 1 ⊕ 3 = 0; 0 ⊕ 0 = 0; 0 ⊕ 1 = 1; 0 ⊕ 2 = 0; 0 ⊕ 3 = 1)
⊗
Modular multiplication of two polynomials over the binary field GF(2) modulo x128+x7+x2+x+1 (GF stands for Galois Field)