/* -*-c-*-
*
- * $Id: xtea.c,v 1.1 2000/07/15 13:44:31 mdw Exp $
+ * $Id: xtea.c,v 1.2 2000/07/29 09:56:47 mdw Exp $
*
* The Extended Tiny Encryption Algorithm
*
/*----- Revision history --------------------------------------------------*
*
* $Log: xtea.c,v $
+ * Revision 1.2 2000/07/29 09:56:47 mdw
+ * Allow the number of rounds to be configured. This isn't exported
+ * through the gcipher interface, but it may be useful anyway.
+ *
* Revision 1.1 2000/07/15 13:44:31 mdw
* New ciphers.
*
p = kb;
}
- k->k[0] = LOAD32(p + 0); k->k[1] = LOAD32(p + 4);
- k->k[2] = LOAD32(p + 8); k->k[3] = LOAD32(p + 12);
+ k->k[0] = LOAD32(p + 0); k->k[1] = LOAD32(p + 4);
+ k->k[2] = LOAD32(p + 8); k->k[3] = LOAD32(p + 12);
+ k->r = 32;
if (p == kb)
BURN(kb);
uint32 n = 0;
unsigned i;
- for (i = 0; i < 32; i++) {
+ for (i = 0; i < k->r; i++) {
y = U32(y + ((((z << 4) ^ (z >> 5)) + z) ^ (n + k->k[n & 3])));
n += DELTA;
z = U32(z + ((((y << 4) ^ (y >> 5)) + y) ^ (n + k->k[(n >> 11) & 3])));
void xtea_dblk(const xtea_ctx *k, const uint32 *s, uint32 *d)
{
uint32 y = s[0], z = s[1];
- uint32 n = DELTA << 5;
+ uint32 n = DELTA * k->r;
unsigned i;
- for (i = 0; i < 32; i++) {
+ for (i = 0; i < k->r; i++) {
z = U32(z - ((((y << 4) ^ (y >> 5)) + y) ^ (n + k->k[(n >> 11) & 3])));
n -= DELTA;
y = U32(y - ((((z << 4) ^ (z >> 5)) + z) ^ (n + k->k[n & 3])));