The Structure of SAFER+ Algorithm for Encryption Round i
“xor” denotes bit-by-bit modulo-two addition of bytes
“add” 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