mirror of
https://github.com/henrydcase/pqc.git
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77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
/**
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* WARNING
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*
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* This file generates a PREDICTABLE and NOT AT ALL RANDOM sequence of bytes.
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*
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* Its purpose is to support our testing suite and it MUST NOT be used in any
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* scenario where you are expecting actual cryptography to happen.
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*/
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#include "randombytes.h"
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#include <stdint.h>
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static uint32_t seed[32] = {3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9, 3,
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2, 3, 8, 4, 6, 2, 6, 4, 3, 3, 8, 3, 2, 7, 9, 5};
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static uint32_t in[12];
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static uint32_t out[8];
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static int32_t outleft = 0;
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#define ROTATE(x, b) (((x) << (b)) | ((x) >> (32 - (b))))
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#define MUSH(i, b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x, b));
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static void surf(void) {
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uint32_t t[12];
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uint32_t x;
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uint32_t sum = 0;
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int32_t r;
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int32_t i;
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int32_t loop;
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for (i = 0; i < 12; ++i) {
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t[i] = in[i] ^ seed[12 + i];
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}
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for (i = 0; i < 8; ++i) {
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out[i] = seed[24 + i];
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}
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x = t[11];
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for (loop = 0; loop < 2; ++loop) {
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for (r = 0; r < 16; ++r) {
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sum += 0x9e3779b9;
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MUSH(0, 5)
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MUSH(1, 7)
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MUSH(2, 9)
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MUSH(3, 13)
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MUSH(4, 5)
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MUSH(5, 7)
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MUSH(6, 9)
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MUSH(7, 13)
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MUSH(8, 5)
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MUSH(9, 7)
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MUSH(10, 9)
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MUSH(11, 13)
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}
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for (i = 0; i < 8; ++i) {
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out[i] ^= t[i + 4];
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}
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}
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}
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void randombytes(uint8_t *x, uint64_t xlen) {
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while (xlen > 0) {
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if (!outleft) {
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if (!++in[0]) {
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if (!++in[1]) {
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if (!++in[2]) {
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++in[3];
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}
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}
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}
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surf();
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outleft = 8;
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}
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*x = out[--outleft];
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++x;
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--xlen;
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}
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}
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