static
void step(rabbit_ctx_t* ctx){
uint32_t g[8];
uint8_t i=0;
update_c(ctx);
gen_g(g, ctx);
memcpy(ctx->x, g, 8*4);
do{
ctx->x[i] += ROT16(g[(i+8-1)%8]) + ROT16(g[(i+8-2)%8]);
++i;
ctx->x[i] += ROT8(g[(i+8-1)%8]) + g[(i+8-2)%8];
}while(++i<8);
}
int seal(seal_ctx *key, unsigned long in, unsigned long *out)
{
int i, j, l;
unsigned long a, b, c, d, n1, n2, n3, n4, *wp;
unsigned short p, q;
wp = out;
for (l = 0; l < 4; l++) {
a = in ^ key->r[4*l];
b = ROT8(in) ^ key->r[4*l+1];
c = ROT16(in) ^ key->r[4*l+2];
d = ROT24(in) ^ key->r[4*l+3];
}
for (j = 0; j < 2; j++) {
p = a & 0x7fc;
b += key->t[p/4];
a = ROT9(a);
p = b & 0x7fc;
c += key->t[p/4];
b = ROT9(b);
p = c & 0x7fc;
d += key->t[p/4];
c = ROT9(c);
p = d & 0x7fc;
a += key->t[p/4];
d = ROT9(d);
n1 = d; n2 = b; n3 = a; n4 = c;
p = a & 0x7fc;
b += key->t[p/4];
a = ROT9(a);
p = b & 0x7fc;
c += key->t[p/4];
b = ROT9(b);
p = c & 0x7fc;
d += key->t[p/4];
c = ROT9(c);
p = d & 0x7fc;
a += key->t[p/4];
d = ROT9(d);
/* This generates 64 32-bit words, or 256 bytes of keystream. */
for (i = 0; i < 64; i++) {
p = a & 0x7fc;
b += key->t[p/4];
a = ROT9(a);
b ^= a;
q = b & 0x7fc;
c ^= key->t[q/4];
b = ROT9(b);
c += b;
p = (p+c) & 0x7fc;
d += key->t[p/4];
c = ROT9(c);
d ^= c;
q = (q+d) & 0x7fc;
a ^= key->t[q/4];
d = ROT9(d);
a += d;
p = (p+a) & 0x7fc;
b ^= key->t[p/4];
a = ROT9(a);
q = (q+b) & 0x7fc;
c += key->t[q/4];
b = ROT9(b);
p = (p+c) & 0x7fc;
d ^= key->t[p/4];
c = ROT9(c);
q = (q+d) & 0x7fc;
a += key->t[q/4];
d = ROT9(d);
*wp = b + key->s[4*i]; wp++;
*wp = c ^ key->s[4*i+1]; wp++;
*wp = d + key->s[4*i+2]; wp++;
*wp = a ^ key->s[4*i+3]; wp++;
if (i & 1) {
a += n3;
c += n4;
} else {
a += n1;
c += n2;
}
}
}
return (ALG_OK);
}
