byte AES::cbc_decrypt (byte * cipher, byte * plain, int n_block)
{
while (n_block--) {
byte tmp [N_BLOCK] ;
copy_n_bytes (tmp, cipher, N_BLOCK) ;
if (decrypt (cipher, plain) != AES_SUCCESS) {
return AES_FAILURE ;
}
xor_block (plain, iv) ;
copy_n_bytes (iv, tmp, N_BLOCK) ;
plain += N_BLOCK ;
cipher += N_BLOCK;
}
return AES_SUCCESS ;
}
byte AES::set_key (byte key [], int keylen)
{
byte hi ;
switch (keylen)
{
case 16:
case 128:
keylen = 16; // 10 rounds
round = 10 ;
break;
case 24:
case 192:
keylen = 24; // 12 rounds
round = 12 ;
break;
case 32:
case 256:
keylen = 32; // 14 rounds
round = 14 ;
break;
default:
round = 0;
return FAILURE;
}
hi = (round + 1) << 4 ;
copy_n_bytes (key_sched, key, keylen) ;
byte t[4] ;
byte next = keylen ;
for (byte cc = keylen, rc = 1 ; cc < hi ; cc += N_COL)
{
for (byte i = 0 ; i < N_COL ; i++)
t[i] = key_sched [cc-4+i] ;
if (cc == next)
{
next += keylen ;
byte ttt = t[0] ;
t[0] = s_box (t[1]) ^ rc ;
t[1] = s_box (t[2]) ;
t[2] = s_box (t[3]) ;
t[3] = s_box (ttt) ;
rc = f2 (rc) ;
}
else if (keylen == 32 && (cc & 31) == 16)
{
for (byte i = 0 ; i < 4 ; i++)
t[i] = s_box (t[i]) ;
}
byte tt = cc - keylen ;
for (byte i = 0 ; i < N_COL ; i++)
key_sched [cc + i] = key_sched [tt + i] ^ t[i] ;
}
return SUCCESS ;
}
byte AES::cbc_encrypt (byte * plain, byte * cipher, int n_block)
{
while (n_block--) {
xor_block (iv, plain) ;
if (encrypt (iv, iv) != AES_SUCCESS) {
return AES_FAILURE ;
}
copy_n_bytes (cipher, iv, N_BLOCK) ;
plain += N_BLOCK ;
cipher += N_BLOCK ;
}
return AES_SUCCESS ;
}
byte AES::cbc_encrypt (byte * plain, byte * cipher, int n_block, byte iv [N_BLOCK])
{
while (n_block--)
{
xor_block (iv, plain) ;
if (encrypt (iv, iv) != SUCCESS)
return FAILURE ;
copy_n_bytes (cipher, iv, N_BLOCK) ;
plain += N_BLOCK ;
cipher += N_BLOCK ;
}
return SUCCESS ;
}
void put_file (int socket, char *filename, int length)
{
struct answer response;
response.errnum = 0;
response.nbbytes = 0;
response.ack = ANSWER_OK;
int file = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
if (file == -1) {
exit(errno);
}
copy_n_bytes (socket, file, length);
if(write (socket, &response, sizeof(response)) == -1) {
exit (errno);
}
} /* put_file */
/*
* Obtention d'un fichier distant.
* 'serverfd' est un socket connecte a la machine 'servername'.
* 'distname' est le nom du fichier a demander, 'localname' est le nom du
* fichier resultat.
*/
void get_file (int serverfd, char *servername, char *distname, char *localname)
{
// REQUEST GET
struct request request_get;
request_get.kind=REQUEST_GET;
strcpy(request_get.path,distname);
// ANSWER GET
struct answer answer_get;
// Envoie de la requete au serveur
if(write(serverfd,&request_get,sizeof(request_get))==-1) {
perror("erreur envoi requette de get\n");
exit(EXIT_FAILURE);
}
//Lecture de la réponse du serveur a la requete
if(read(serverfd,&answer_get,sizeof(answer_get))==-1){
perror("erreur lors de la lecture de la reponse\n");
exit(EXIT_FAILURE);
}
// CHECK ack GET
check_answer(&answer_get);
// Création d'n fichier
int fd= open(localname, O_WRONLY | O_CREAT| O_EXCL, 0644);
if (fd == -1) {
perror("Erreur de creation du fichier\n");
exit(EXIT_FAILURE);
}
else {
// Récuperation des données
printf("Debut de la recuperation du fichier\n");
int taille=answer_get.nbbytes;
copy_n_bytes(serverfd,fd,taille);
printf("Recuperation terminee\n");
close(fd);
}
}
void copy_bytes(char* from, char* to) {
copy_n_bytes(from, to, BLOCK_SIZE);
}
