// Perform the key expansion for AES-128 using 16-byte key; each round stored in round_key
// Pseudocode taken from Fig.11 in FIPS-197 (page 20)
void key_expansion(unsigned char init_key[16], unsigned char round_key[44][4], FILE* table) {
unsigned char* temp = (unsigned char*)calloc(1,4);
unsigned char* s_box = (unsigned char*)calloc(1,256);
unsigned char* rcon = (unsigned char*)calloc(1,256);
init_s_box(s_box, table);
init_rcon(rcon);
// Store initial round keys (form words from each piece of init key)
for(int i=0; i<4; i++) {
round_key[i][0] = init_key[4*i];
round_key[i][1] = init_key[4*i+1];
round_key[i][2] = init_key[4*i+2];
round_key[i][3] = init_key[4*i+3];
// Tried defining round key as a WORD (unsigned int), but I forgot there are
// little-endian/big-endian issues with different architectures. F**k that.
}
// Generate subsequent round keys (from Nk -> Nb*(Nr+1))
for(int i=4; i<44; i++) {
// Set temp var to previous round key
temp[0] = round_key[i-1][0];
temp[1] = round_key[i-1][1];
temp[2] = round_key[i-1][2];
temp[3] = round_key[i-1][3];
// Perform Rijndael key schedule core every 4 iterations
if (i%4 == 0) {
// For AES-128 and AES-192; rotate temp vals, put through s_box, xor the MSB with rcon
rot_word(temp);
temp[0] = s_box[ temp[0] ] ^ rcon[i/4];
temp[1] = s_box[ temp[1] ];
temp[2] = s_box[ temp[2] ];
temp[3] = s_box[ temp[3] ];
}
// Store current round key
round_key[i][0] = round_key[i-4][0] ^ temp[0];
round_key[i][1] = round_key[i-4][1] ^ temp[1];
round_key[i][2] = round_key[i-4][2] ^ temp[2];
round_key[i][3] = round_key[i-4][3] ^ temp[3];
}
free(temp);
free(s_box);
free(rcon);
}
int op_3(char **strarray, long N)
{
long perm;
scanf("%li", &perm);
int i, j;
int inceput;
int stare = 0; //0-nu suntem in cuvant 1-suntem in cuvant
for (i = 0 ; i < N ; i++)
{
for (j = 0 ; j <= strlen(strarray[i]) ; j++)
{
// <= pt ca luam si backslash 0
if (stare == 0)
{
if ( ! (one_of(&strarray[i][j])) )
{
//daca am ajuns la un cuvant;
inceput = j;
stare = 1;
}
}
else //daca stare==1
{
if (one_of(&strarray[i][j]))
{
stare = 0;
rot_word(strarray[i], inceput, j, perm);
}
}
}
}
printare(strarray, N);
return 0;
}
/*
* Key Expansion
*/
void key_expansion(uint8_t *key, uint8_t *w) {
uint8_t tmp[4];
uint8_t i, j;
uint8_t len = Nb*(Nr+1);
for (i = 0; i < Nk; i++) {
w[4*i+0] = key[4*i+0];
w[4*i+1] = key[4*i+1];
w[4*i+2] = key[4*i+2];
w[4*i+3] = key[4*i+3];
}
for (i = Nk; i < len; i++) {
tmp[0] = w[4*(i-1)+0];
tmp[1] = w[4*(i-1)+1];
tmp[2] = w[4*(i-1)+2];
tmp[3] = w[4*(i-1)+3];
if (i%Nk == 0) {
rot_word(tmp);
sub_word(tmp);
coef_add(tmp, Rcon(i/Nk), tmp);
} else if (Nk > 6 && i%Nk == 4) {
sub_word(tmp);
}
w[4*i+0] = w[4*(i-Nk)+0]^tmp[0];
w[4*i+1] = w[4*(i-Nk)+1]^tmp[1];
w[4*i+2] = w[4*(i-Nk)+2]^tmp[2];
w[4*i+3] = w[4*(i-Nk)+3]^tmp[3];
}
}
