AMPRNG rev1.0 core routines for PARANOID mode of pseudo-random generator

Secure pseudo-random stream generator and stream cipher,
initialized by 80-512 bit key and (optional) 80-128 bit IV

usage:

Create (key, key_length, is_iv_used, drop_length)

if is_iv_used set, then call
SetIV (iv, iv_length)

to get output,
use PRNG() or GenetateRandom()

to crypt,
use Crypt()



2. AMPRNG pseudo-random generator test utility

Generates random file,
such file you can test by ENT or DIEHARD batterry.

usage: amprng <output file>



*/


#include "amprng.h"



#include "sbox.h"

u8 P[256], MG[256], m, z, savedkey[256];
s32 pos, savedkl, droplen;



#define Morph for (i = 0; i != kl; i++) SEED[i] = MKBOX[SEED[i]];

#define Cycle \
for (i = 0; i != 2048; i++) \
{ \
idx = i & 255; \
m = P[(P[idx] + NL[(m + TK[(SEED[i & (kl - 1)] + idx) & 255]) & 255]) & 255]; \
t = P[idx]; \
P[idx] = P[m]; \
P[m] = t; \
} \


#define MGCycle \
for (i = 0; i != 2048; i++) \
{ \
idx = i & 255; \
z = MG[(MG[idx] + NL[(z + TK[(SEED[i & (kl - 1)] + idx) & 255]) & \
255]) & 255]; \
t = MG[idx]; \
MG[idx] = MG[z]; \
MG[z] = t; \
} \



#define SWAP1 \
for (i = 0; i != 256; i++) \
{ \
T[i] = P[i]; \
P[i] = NL[i]; \
NL[i] = T[i]; \
} \



#define SWAP2 \
for (i = 0; i != 256; i++) \
{ \
T[i] = P[i]; \
P[i] = TK[i]; \
TK[i] = T[i]; \
} \



#define SWAP3 \
for (i = 0; i != 256; i++) \
{ \
T[i] = NL[i]; \
NL[i] = TK[i]; \
TK[i] = T[i]; \
} \



void setup(const u8 *key, s32 kl, s32 iv)
{
s32 i, idx;
u8 t, NL[256], TK[256], SEED[256], T[256];

for (i = 0; i != kl; i++)
SEED[i] = key[i];

for (i = 0; i != 256; i++)
{
if (iv == 0) P[i] = i;

NL[i] = NLBOX[i];
TK[i] = TKBOX[i];
}


m = 0;

Morph;
Cycle;
SWAP1;
Morph;
Cycle;
SWAP2;
Morph;
Cycle;
SWAP1;
Morph;
Cycle;
Morph;
SWAP3;
Morph;

if (iv == 0)
{
for (i = 0; i != 256; i++)
MG[i] = MGBOX[i];

}

z = 0;
MGCycle;
pos = 0;

}




void Create(const u8 *key, s32 kl, s32 useiv, s32 drop)
{
s32 i;

setup(key, kl, 0);

if ((useiv == 1))
{
savedkl = kl;

for (i = 0; i != kl; i++)
savedkey[i] = key[i];

}

droplen = drop;
}



void SetIV(const u8 *iv, s32 ivl)
{
s32 i;

setup(iv, ivl, 1);
setup(savedkey, savedkl, 1);

for (i = 0; i != 256; i++) savedkey[i] = 0;
savedkl = 0;

}



u8 PRNG (void)
{
u8 t, output;

if (droplen == 0) droplen = 1;

do
{
m = P[MG[(m + P[pos]) & 255]];
z = MG[P[(z + MG[pos]) & 255]];
output = P[P[(P[m] + 1) & 255]];
t = P[pos];
P[pos] = P[m];
P[m] = t;
t = MG[pos];
MG[pos] = MG[z];
MG[z] = t;
pos = (pos + 1) & 255;
droplen-- ;
}

while (droplen != 0);


return output;

}



void GenerateRandom(u8 *buffer, s32 len)
{
s32 i;

for (i = 0; i != len; i++)
buffer[i] = PRNG();
}


void Crypt(u8 *buffer, s32 len)
{
s32 i;

for (i = 0; i != len; i++)
buffer[i] = buffer[i] ^ PRNG();

}



#ifdef PRNG_TEST

#include <stdio.h>

int
main (int argc, u8 *argv[])
{
FILE *f;
u8 buffer [512], key[64], iv[64];
s32 i, n;

if (argc < 2)
{
fprintf (stderr, "usage: %s <output filename>\n", argv[0]);
return (1);
}
if ((f = fopen (argv[1], "wb+")) == NULL)
{
fprintf (stderr, "failed to open '%s' for writing.\n", argv[1]);
return (1);
}


for (i = 0; i != 64; i++)
{
key[i] = i & 5;
iv[i] = i & 2;
}

Create(key, 64, 1, 768);
SetIV(iv, 64);

for (i = 0; i != 1024 * 1024; i++)
{
GenerateRandom(buffer, 128);
fwrite (buffer, 128, 1, f);
}

fclose (f);
return (0);
}


#endif