The Structure of SAFER+ Algorithm for Decryption Round I

Round Input (16 Bytes)

Operate with Invertible Linear Tranformation 16 by 16 matrix M-1

sub xor xor sub sub xor xor sub sub xor xor sub sub xor xor sub

log exp exp log log exp exp log log exp exp log log exp exp log

xor sub sub xor xor sub sub xor xor sub sub xor xor sub sub xor

K2r-2i+2

K2r-2i+1

“xor” denotes bit-by-bit modulo-two addition of bytes

“sub” denotes modulo-256 addition of bytes

“exp” denotes 45x modulo 257, with the convention

that the result 45128=256 is represented by 0

“log” denotes log45(x), with the convention that log45(0)=128

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