rijndael-alg-ref.c [plain text]
#include <stdio.h>
#include <stdlib.h>
#include "rijndael-alg-ref.h"
#define SC ((BC - 4) >> 1)
#include "boxes-ref.h"
static const word8 shifts[3][4][2] = {
{ { 0, 0 },
{ 1, 3 },
{ 2, 2 },
{ 3, 1 }
},
{ { 0, 0 },
{ 1, 5 },
{ 2, 4 },
{ 3, 3 }
},
{ { 0, 0 },
{ 1, 7 },
{ 3, 5 },
{ 4, 4 }
}
};
static word8 mul(word8 a, word8 b) {
if (a && b) return Alogtable[(Logtable[a] + Logtable[b])%255];
else return 0;
}
static void KeyAddition(word8 a[4][MAXBC], word8 rk[4][MAXBC], word8 BC) {
int i, j;
for(i = 0; i < 4; i++)
for(j = 0; j < BC; j++) a[i][j] ^= rk[i][j];
}
static void ShiftRow(word8 a[4][MAXBC], word8 d, word8 BC) {
word8 tmp[MAXBC];
int i, j;
for(i = 1; i < 4; i++) {
for(j = 0; j < BC; j++) tmp[j] = a[i][(j + shifts[SC][i][d]) % BC];
for(j = 0; j < BC; j++) a[i][j] = tmp[j];
}
}
static void Substitution(word8 a[4][MAXBC], const word8 box[256], word8 BC) {
int i, j;
for(i = 0; i < 4; i++)
for(j = 0; j < BC; j++) a[i][j] = box[a[i][j]] ;
}
static void MixColumn(word8 a[4][MAXBC], word8 BC) {
word8 b[4][MAXBC];
int i, j;
for(j = 0; j < BC; j++)
for(i = 0; i < 4; i++)
b[i][j] = mul(2,a[i][j])
^ mul(3,a[(i + 1) % 4][j])
^ a[(i + 2) % 4][j]
^ a[(i + 3) % 4][j];
for(i = 0; i < 4; i++)
for(j = 0; j < BC; j++) a[i][j] = b[i][j];
}
static void InvMixColumn(word8 a[4][MAXBC], word8 BC) {
word8 b[4][MAXBC];
int i, j;
for(j = 0; j < BC; j++)
for(i = 0; i < 4; i++)
b[i][j] = mul(0xe,a[i][j])
^ mul(0xb,a[(i + 1) % 4][j])
^ mul(0xd,a[(i + 2) % 4][j])
^ mul(0x9,a[(i + 3) % 4][j]);
for(i = 0; i < 4; i++)
for(j = 0; j < BC; j++) a[i][j] = b[i][j];
}
int _rijndaelKeySched (word8 k[4][MAXKC], int keyBits, int blockBits, word8 W[MAXROUNDS+1][4][MAXBC]) {
int KC, BC, ROUNDS;
int i, j, t, rconpointer = 0;
word8 tk[4][MAXKC];
switch (keyBits) {
case 128: KC = 4; break;
case 192: KC = 6; break;
case 256: KC = 8; break;
default : return (-1);
}
switch (blockBits) {
case 128: BC = 4; break;
case 192: BC = 6; break;
case 256: BC = 8; break;
default : return (-2);
}
switch (keyBits >= blockBits ? keyBits : blockBits) {
case 128: ROUNDS = 10; break;
case 192: ROUNDS = 12; break;
case 256: ROUNDS = 14; break;
default : return (-3);
}
for(j = 0; j < KC; j++)
for(i = 0; i < 4; i++)
tk[i][j] = k[i][j];
t = 0;
for(j = 0; (j < KC) && (t < (ROUNDS+1)*BC); j++, t++)
for(i = 0; i < 4; i++) W[t / BC][i][t % BC] = tk[i][j];
while (t < (ROUNDS+1)*BC) {
for(i = 0; i < 4; i++)
tk[i][0] ^= S[tk[(i+1)%4][KC-1]];
tk[0][0] ^= rcon[rconpointer++];
if (KC != 8)
for(j = 1; j < KC; j++)
for(i = 0; i < 4; i++) tk[i][j] ^= tk[i][j-1];
else {
for(j = 1; j < KC/2; j++)
for(i = 0; i < 4; i++) tk[i][j] ^= tk[i][j-1];
for(i = 0; i < 4; i++) tk[i][KC/2] ^= S[tk[i][KC/2 - 1]];
for(j = KC/2 + 1; j < KC; j++)
for(i = 0; i < 4; i++) tk[i][j] ^= tk[i][j-1];
}
for(j = 0; (j < KC) && (t < (ROUNDS+1)*BC); j++, t++)
for(i = 0; i < 4; i++) W[t / BC][i][t % BC] = tk[i][j];
}
return 0;
}
int _rijndaelEncrypt (word8 a[4][MAXBC], int keyBits, int blockBits, word8 rk[MAXROUNDS+1][4][MAXBC])
{
int r, BC, ROUNDS;
switch (blockBits) {
case 128: BC = 4; break;
case 192: BC = 6; break;
case 256: BC = 8; break;
default : return (-2);
}
switch (keyBits >= blockBits ? keyBits : blockBits) {
case 128: ROUNDS = 10; break;
case 192: ROUNDS = 12; break;
case 256: ROUNDS = 14; break;
default : return (-3);
}
KeyAddition(a,rk[0],BC);
for(r = 1; r < ROUNDS; r++) {
Substitution(a,S,BC);
ShiftRow(a,0,BC);
MixColumn(a,BC);
KeyAddition(a,rk[r],BC);
}
Substitution(a,S,BC);
ShiftRow(a,0,BC);
KeyAddition(a,rk[ROUNDS],BC);
return 0;
}
#ifndef __APPLE__
int rijndaelEncryptRound (word8 a[4][MAXBC], int keyBits, int blockBits,
word8 rk[MAXROUNDS+1][4][MAXBC], int rounds)
{
int r, BC, ROUNDS;
switch (blockBits) {
case 128: BC = 4; break;
case 192: BC = 6; break;
case 256: BC = 8; break;
default : return (-2);
}
switch (keyBits >= blockBits ? keyBits : blockBits) {
case 128: ROUNDS = 10; break;
case 192: ROUNDS = 12; break;
case 256: ROUNDS = 14; break;
default : return (-3);
}
if (rounds > ROUNDS) rounds = ROUNDS;
KeyAddition(a,rk[0],BC);
for(r = 1; (r <= rounds) && (r < ROUNDS); r++) {
Substitution(a,S,BC);
ShiftRow(a,0,BC);
MixColumn(a,BC);
KeyAddition(a,rk[r],BC);
}
if (rounds == ROUNDS) {
Substitution(a,S,BC);
ShiftRow(a,0,BC);
KeyAddition(a,rk[ROUNDS],BC);
}
return 0;
}
#endif
int _rijndaelDecrypt (word8 a[4][MAXBC], int keyBits, int blockBits, word8 rk[MAXROUNDS+1][4][MAXBC])
{
int r, BC, ROUNDS;
switch (blockBits) {
case 128: BC = 4; break;
case 192: BC = 6; break;
case 256: BC = 8; break;
default : return (-2);
}
switch (keyBits >= blockBits ? keyBits : blockBits) {
case 128: ROUNDS = 10; break;
case 192: ROUNDS = 12; break;
case 256: ROUNDS = 14; break;
default : return (-3);
}
KeyAddition(a,rk[ROUNDS],BC);
Substitution(a,Si,BC);
ShiftRow(a,1,BC);
for(r = ROUNDS-1; r > 0; r--) {
KeyAddition(a,rk[r],BC);
InvMixColumn(a,BC);
Substitution(a,Si,BC);
ShiftRow(a,1,BC);
}
KeyAddition(a,rk[0],BC);
return 0;
}
#ifndef __APPLE__
int rijndaelDecryptRound (word8 a[4][MAXBC], int keyBits, int blockBits,
word8 rk[MAXROUNDS+1][4][MAXBC], int rounds)
{
int r, BC, ROUNDS;
switch (blockBits) {
case 128: BC = 4; break;
case 192: BC = 6; break;
case 256: BC = 8; break;
default : return (-2);
}
switch (keyBits >= blockBits ? keyBits : blockBits) {
case 128: ROUNDS = 10; break;
case 192: ROUNDS = 12; break;
case 256: ROUNDS = 14; break;
default : return (-3);
}
if (rounds > ROUNDS) rounds = ROUNDS;
KeyAddition(a,rk[ROUNDS],BC);
Substitution(a,Si,BC);
ShiftRow(a,1,BC);
for(r = ROUNDS-1; r > rounds; r--) {
KeyAddition(a,rk[r],BC);
InvMixColumn(a,BC);
Substitution(a,Si,BC);
ShiftRow(a,1,BC);
}
if (rounds == 0) {
KeyAddition(a,rk[0],BC);
}
return 0;
}
#endif