mirror of
https://github.com/trezor/trezor-firmware.git
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92 lines
1.8 KiB
C
92 lines
1.8 KiB
C
#if defined(ED25519_TEST)
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/*
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ISAAC+ "variant", the paper is not clear on operator precedence and other
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things. This is the "first in, first out" option!
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Not threadsafe or securely initialized, only for deterministic testing
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*/
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typedef struct isaacp_state_t {
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uint32_t state[256];
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unsigned char buffer[1024];
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uint32_t a, b, c;
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size_t left;
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} isaacp_state;
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#define isaacp_step(offset, mix) \
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x = mm[i + offset]; \
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a = (a ^ (mix)) + (mm[(i + offset + 128) & 0xff]); \
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y = (a ^ b) + mm[(x >> 2) & 0xff]; \
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mm[i + offset] = y; \
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b = (x + a) ^ mm[(y >> 10) & 0xff]; \
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U32TO8_LE(out + (i + offset) * 4, b);
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static void
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isaacp_mix(isaacp_state *st) {
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uint32_t i, x, y;
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uint32_t a = st->a, b = st->b, c = st->c;
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uint32_t *mm = st->state;
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unsigned char *out = st->buffer;
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c = c + 1;
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b = b + c;
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for (i = 0; i < 256; i += 4) {
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isaacp_step(0, ROTL32(a,13))
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isaacp_step(1, ROTR32(a, 6))
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isaacp_step(2, ROTL32(a, 2))
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isaacp_step(3, ROTR32(a,16))
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}
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st->a = a;
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st->b = b;
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st->c = c;
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st->left = 1024;
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}
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static void
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isaacp_random(isaacp_state *st, void *p, size_t len) {
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size_t use;
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unsigned char *c = (unsigned char *)p;
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while (len) {
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use = (len > st->left) ? st->left : len;
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memcpy(c, st->buffer + (sizeof(st->buffer) - st->left), use);
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st->left -= use;
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c += use;
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len -= use;
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if (!st->left)
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isaacp_mix(st);
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}
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}
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void
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ED25519_FN(ed25519_randombytes_unsafe) (void *p, size_t len) {
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static int initialized = 0;
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static isaacp_state rng;
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if (!initialized) {
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memset(&rng, 0, sizeof(rng));
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isaacp_mix(&rng);
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isaacp_mix(&rng);
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initialized = 1;
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}
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isaacp_random(&rng, p, len);
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}
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#elif defined(ED25519_CUSTOMRANDOM)
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#include "ed25519-randombytes-custom.h"
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#else
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#include <openssl/rand.h>
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void
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ED25519_FN(ed25519_randombytes_unsafe) (void *p, size_t len) {
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RAND_bytes(p, (int) len);
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}
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#endif
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