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

Table 3

The SBN instruction sets.

Instruction sets	Description	3-Tuple instruction format
SBN ADD/SUBTRACT	2 SBN instructions would result in an addition operation. Hence, B−(−A)=A+B, and the value of (A + B) is stored in the B address	(1) SBN $A, $C, 0; (C = −A), where the address C contains the value of zero and A is the input A; (2) SBN $C, $B, 0; B−(−A)=B+A, where the address B contains the value of input B
SBN MOVE/COPY	2 SBN instructions would result in a MOVE operation. Hence, D = A, and the value of A is stored in the D address	(1) SBN $A, $C, 0; (C = −A), where the address C contains the value of zero and A is the input A; (2) SBN $C, $D, 0; (D = +A), where the address D contains the value of zero
SBN JUMP	1 SBN instruction would result in a JUMP operation. The condition would be the resultant output of 𝑋−𝑌=𝑎 negative value	SBN $𝑋, $𝑌, $J; (J = jump address),; where 𝑋−𝑌 = −ve (value)
SBN CLEAR	1 SBN instruction would result in a CLR memory operation	SBN $A, $A, 0; (A − A = 0), where the address A contains the value of input A