Digital Design of Communication Systems - Digital Design of Signal Processing Systems: A Practical Approach - page 544

h + s + h 7

h 0 s 0 h 1 s 1 h 2 s 2 h 3 s 3

= = = =

= = = = = = = =

. . . . . . . . . . . . . . . . . . . . .

h 7 s 0 s 0 s 1 s 1 s 1

= = = = = =

s 2 s 3

. . . . . . . . . . . . . . . . . . . . .

= =

s 3 s 4

= =

s 6 s 7

= =

Pointers lengths

Figure 13.23 Digital design implementing multiple iterations of the LZ77 algorithm

// Nb = 4
// Nr = 10, 12, 14 for 128, 192 and 256 bit AES
// Hard parameter, Nk=4,6,8 for 128, 192, 256 AES
// UWord8 and UWord32 are 8-bit and 32-bit unsigned numbers
UWord32 key[Nk];
UWord32 w[Nb*(Nr-1)]; /* Expended Key */
AES_encryption (
UWord8 plain_text[4*Nb],
UWord8 cipher_text[4*Nb],
UWord32 w[Nb*(Nr-1)]);
begin
UWord8 state [4*Nb];
state = Plain_text;
ARK(state, w[0, Nb-1]);
for(round=1, round<=Nr-1, round++)
begin
SB(state);
SR(state);
MC(state);
ARK(state, w[round*Nb, (round+1)*Nb-1)]);

end
SB(state);
SR(state);
ARK(state, w[Nr*Nb, (Nr+1)*Nb-1)]);

end