Revision e7a83922d58f144cedb993cf9f98c63d1080ac7f authored by Thom Wiggers on 17 September 2020, 08:23:24 UTC, committed by John M. Schanck on 26 November 2020, 18:10:21 UTC
1 parent c99c406
sp800-185.c
#include <stddef.h>
#include <stdint.h>
#include "sp800-185.h"
static size_t left_encode(uint8_t *encbuf, size_t value) {
size_t n, i, v;
for (v = value, n = 0; v && (n < sizeof(size_t)); n++, v >>= 8) {
; /* empty */
}
if (n == 0) {
n = 1;
}
for (i = 1; i <= n; i++) {
encbuf[i] = (uint8_t)(value >> (8 * (n-i)));
}
encbuf[0] = (uint8_t)n;
return n + 1;
}
void cshake128_inc_init(shake128incctx *state, const uint8_t *name, size_t namelen, const uint8_t *cstm, size_t cstmlen) {
uint8_t encbuf[sizeof(size_t)+1];
shake128_inc_init(state);
shake128_inc_absorb(state, encbuf, left_encode(encbuf, SHAKE128_RATE));
shake128_inc_absorb(state, encbuf, left_encode(encbuf, namelen * 8));
shake128_inc_absorb(state, name, namelen);
shake128_inc_absorb(state, encbuf, left_encode(encbuf, cstmlen * 8));
shake128_inc_absorb(state, cstm, cstmlen);
if (state->ctx[25] != 0) {
state->ctx[25] = SHAKE128_RATE - 1;
encbuf[0] = 0;
shake128_inc_absorb(state, encbuf, 1);
}
}
void cshake128_inc_absorb(shake128incctx *state, const uint8_t *input, size_t inlen) {
shake128_inc_absorb(state, input, inlen);
}
void cshake128_inc_finalize(shake128incctx *state) {
state->ctx[state->ctx[25] >> 3] ^= (uint64_t)0x04 << (8 * (state->ctx[25] & 0x07));
state->ctx[(SHAKE128_RATE - 1) >> 3] ^= (uint64_t)128 << (8 * ((SHAKE128_RATE - 1) & 0x07));
state->ctx[25] = 0;
}
void cshake128_inc_squeeze(uint8_t *output, size_t outlen, shake128incctx *state) {
shake128_inc_squeeze(output, outlen, state);
}
void cshake128_inc_ctx_release(shake128incctx *state) {
shake128_inc_ctx_release(state);
}
void cshake128_inc_ctx_clone(shake128incctx *dest, const shake128incctx *src) {
shake128_inc_ctx_clone(dest, src);
}
void cshake256_inc_init(shake256incctx *state, const uint8_t *name, size_t namelen, const uint8_t *cstm, size_t cstmlen) {
uint8_t encbuf[sizeof(size_t)+1];
shake256_inc_init(state);
shake256_inc_absorb(state, encbuf, left_encode(encbuf, SHAKE256_RATE));
shake256_inc_absorb(state, encbuf, left_encode(encbuf, namelen * 8));
shake256_inc_absorb(state, name, namelen);
shake256_inc_absorb(state, encbuf, left_encode(encbuf, cstmlen * 8));
shake256_inc_absorb(state, cstm, cstmlen);
if (state->ctx[25] != 0) {
state->ctx[25] = SHAKE256_RATE - 1;
encbuf[0] = 0;
shake256_inc_absorb(state, encbuf, 1);
}
}
void cshake256_inc_absorb(shake256incctx *state, const uint8_t *input, size_t inlen) {
shake256_inc_absorb(state, input, inlen);
}
void cshake256_inc_finalize(shake256incctx *state) {
state->ctx[state->ctx[25] >> 3] ^= (uint64_t)0x04 << (8 * (state->ctx[25] & 0x07));
state->ctx[(SHAKE256_RATE - 1) >> 3] ^= (uint64_t)128 << (8 * ((SHAKE256_RATE - 1) & 0x07));
state->ctx[25] = 0;
}
void cshake256_inc_squeeze(uint8_t *output, size_t outlen, shake256incctx *state) {
shake256_inc_squeeze(output, outlen, state);
}
void cshake256_inc_ctx_release(shake256incctx *state) {
shake256_inc_ctx_release(state);
}
void cshake256_inc_ctx_clone(shake256incctx *dest, const shake256incctx *src) {
shake256_inc_ctx_clone(dest, src);
}
/*************************************************
* Name: cshake128
*
* Description: cSHAKE128 XOF with non-incremental API
*
* Arguments: - uint8_t *output: pointer to output
* - size_t outlen: requested output length in bytes
* - const uint8_t *name: pointer to function-name string
* - size_t namelen: length of function-name string in bytes
* - const uint8_t *cstm: pointer to non-empty customization string
* - size_t cstmlen: length of customization string in bytes
* - const uint8_t *input: pointer to input
* - size_t inlen: length of input in bytes
**************************************************/
void cshake128(uint8_t *output, size_t outlen,
const uint8_t *name, size_t namelen,
const uint8_t *cstm, size_t cstmlen,
const uint8_t *input, size_t inlen) {
shake128incctx state;
cshake128_inc_init(&state, name, namelen, cstm, cstmlen);
cshake128_inc_absorb(&state, input, inlen);
cshake128_inc_finalize(&state);
cshake128_inc_squeeze(output, outlen, &state);
cshake128_inc_ctx_release(&state);
}
/*************************************************
* Name: cshake256
*
* Description: cSHAKE256 XOF with non-incremental API
*
* Arguments: - uint8_t *output: pointer to output
* - size_t outlen: requested output length in bytes
* - const uint8_t *name: pointer to function-name string
* - size_t namelen: length of function-name string in bytes
* - const uint8_t *cstm: pointer to non-empty customization string
* - size_t cstmlen: length of customization string in bytes
* - const uint8_t *input: pointer to input
* - size_t inlen: length of input in bytes
**************************************************/
void cshake256(uint8_t *output, size_t outlen,
const uint8_t *name, size_t namelen,
const uint8_t *cstm, size_t cstmlen,
const uint8_t *input, size_t inlen) {
shake256incctx state;
cshake256_inc_init(&state, name, namelen, cstm, cstmlen);
cshake256_inc_absorb(&state, input, inlen);
cshake256_inc_finalize(&state);
cshake256_inc_squeeze(output, outlen, &state);
cshake256_inc_ctx_release(&state);
}
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