A Very Compact AES-SPIHT Selective Encryption Computer Architecture Design with Improved S-Box

Algorithm 1

The CISA instruction sets in pseudocode form.

SBN (Subtract and Branch If Negative)

Mem_B = Mem_B − Mem_A

If Mem_B < 0 Goto (PC + C)

Else Goto (PC + 1)

XOR

Mem_B = Mem_B XOR Mem_A

xTime

Mem_B = xTime(Mem_B)

Sub Bytes

Mem_B = Sub_Bytes(Mem_B)