/**
Read from the PRNG
@param out Destination
@param outlen Length of output
@param prng The active PRNG to read from
@return Number of octets read
*/
unsigned long sober128_read(unsigned char *out, unsigned long outlen, prng_state *prng)
{
struct sober128_prng *c;
ulong32 t, tlen;
LTC_ARGCHK(out != NULL);
LTC_ARGCHK(prng != NULL);
#ifdef LTC_VALGRIND
zeromem(out, outlen);
#endif
c = &(prng->sober128);
t = 0;
tlen = outlen;
/* handle any previously buffered bytes */
while (c->nbuf != 0 && outlen != 0) {
*out++ ^= c->sbuf & 0xFF;
c->sbuf >>= 8;
c->nbuf -= 8;
--outlen;
}
#ifndef LTC_SMALL_CODE
/* do lots at a time, if there's enough to do */
while (outlen >= N*4) {
SROUND(0);
SROUND(1);
SROUND(2);
SROUND(3);
SROUND(4);
SROUND(5);
SROUND(6);
SROUND(7);
SROUND(8);
SROUND(9);
SROUND(10);
SROUND(11);
SROUND(12);
SROUND(13);
SROUND(14);
SROUND(15);
SROUND(16);
out += 4*N;
outlen -= 4*N;
}
#endif
/* do small or odd size buffers the slow way */
while (4 <= outlen) {
cycle(c->R);
t = nltap(c);
XORWORD(t, out);
out += 4;
outlen -= 4;
}
/* handle any trailing bytes */
if (outlen != 0) {
cycle(c->R);
c->sbuf = nltap(c);
c->nbuf = 32;
while (c->nbuf != 0 && outlen != 0) {
*out++ ^= c->sbuf & 0xFF;
c->sbuf >>= 8;
c->nbuf -= 8;
--outlen;
}
}
void
s128_stream(s128_ctx *c, UCHAR *buf, int nbytes)
{
UCHAR *endbuf;
WORD t = 0;
if ((nbytes & 3) != 0)
abort();
endbuf = &buf[nbytes];
/* do small or odd size buffers the slow way, at least at first */
while ((nbytes % (N*4)) != 0) {
cycle(c->R);
t = nltap(c);
XORWORD(t, buf);
buf += 4;
nbytes -= 4;
}
/* now do lots at a time, if there's any left */
while (buf < endbuf)
{
SROUND(0);
SROUND(1);
SROUND(2);
SROUND(3);
SROUND(4);
SROUND(5);
SROUND(6);
SROUND(7);
SROUND(8);
SROUND(9);
SROUND(10);
SROUND(11);
SROUND(12);
SROUND(13);
SROUND(14);
SROUND(15);
SROUND(16);
buf += 4*17;
}
}
unsigned long sober128_read(unsigned char *buf, unsigned long nbytes, sober128_prng *c)
{
ulong32 t, tlen;
tlen = nbytes;
/* handle any previously buffered bytes */
while (c->nbuf != 0 && nbytes != 0) {
*buf++ ^= c->sbuf & 0xFF;
c->sbuf >>= 8;
c->nbuf -= 8;
--nbytes;
}
#ifndef SMALL_CODE
/* do lots at a time, if there's enough to do */
while (nbytes >= N*4) {
SROUND(0);
SROUND(1);
SROUND(2);
SROUND(3);
SROUND(4);
SROUND(5);
SROUND(6);
SROUND(7);
SROUND(8);
SROUND(9);
SROUND(10);
SROUND(11);
SROUND(12);
SROUND(13);
SROUND(14);
SROUND(15);
SROUND(16);
buf += 4*N;
nbytes -= 4*N;
}
#endif
/* do small or odd size buffers the slow way */
while (4 <= nbytes) {
cycle(c->R);
t = nltap(c);
XORWORD(t, buf);
buf += 4;
nbytes -= 4;
}
/* handle any trailing bytes */
if (nbytes != 0) {
cycle(c->R);
c->sbuf = nltap(c);
c->nbuf = 32;
while (c->nbuf != 0 && nbytes != 0) {
*buf++ ^= c->sbuf & 0xFF;
c->sbuf >>= 8;
c->nbuf -= 8;
--nbytes;
}
}
/**
Encrypt (or decrypt) bytes of ciphertext (or plaintext) with Sober128
@param c The Sober128 state
@param in The plaintext (or ciphertext)
@param inlen The length of the input (octets)
@param out [out] The ciphertext (or plaintext), length inlen
@return CRYPT_OK if successful
*/
int sober128_stream_crypt(sober128_state *c, const unsigned char *in, unsigned long inlen, unsigned char *out)
{
ulong32 t;
if (inlen == 0) return CRYPT_OK; /* nothing to do */
LTC_ARGCHK(out != NULL);
LTC_ARGCHK(c != NULL);
/* handle any previously buffered bytes */
while (c->nbuf != 0 && inlen != 0) {
*out++ = *in++ ^ (unsigned char)(c->sbuf & 0xFF);
c->sbuf >>= 8;
c->nbuf -= 8;
--inlen;
}
#ifndef LTC_SMALL_CODE
/* do lots at a time, if there's enough to do */
while (inlen >= N*4) {
SROUND(0);
SROUND(1);
SROUND(2);
SROUND(3);
SROUND(4);
SROUND(5);
SROUND(6);
SROUND(7);
SROUND(8);
SROUND(9);
SROUND(10);
SROUND(11);
SROUND(12);
SROUND(13);
SROUND(14);
SROUND(15);
SROUND(16);
out += 4*N;
in += 4*N;
inlen -= 4*N;
}
#endif
/* do small or odd size buffers the slow way */
while (4 <= inlen) {
cycle(c->R);
t = nltap(c);
XORWORD(t, in, out);
out += 4;
in += 4;
inlen -= 4;
}
/* handle any trailing bytes */
if (inlen != 0) {
cycle(c->R);
c->sbuf = nltap(c);
c->nbuf = 32;
while (c->nbuf != 0 && inlen != 0) {
*out++ = *in++ ^ (unsigned char)(c->sbuf & 0xFF);
c->sbuf >>= 8;
c->nbuf -= 8;
--inlen;
}
}
