| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229 |
- /* ===================================================================
- *
- * Copyright (c) 2014, Legrandin <helderijs@gmail.com>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- * ===================================================================
- */
- #include "pycrypto_common.h"
- FAKE_INIT(chacha20)
- #define KEY_SIZE 32
- #define NONCE_SIZE 8
- typedef struct {
- /** Initial state for the next iteration **/
- uint32_t h[16];
- /** How many bytes at the beginning of the key stream
- * have already been used.
- */
- uint8_t usedKeyStream;
- uint8_t keyStream[sizeof(uint32_t)*16];
- } stream_state;
- static int littleEndian(void) {
- int test = 1;
- return *((uint8_t*)&test) == 1;
- }
- static void byteSwap(uint32_t *v)
- {
- union {
- uint32_t w;
- uint8_t b[4];
- } x, y;
- x.w = *v;
- y.b[0] = x.b[3];
- y.b[1] = x.b[2];
- y.b[2] = x.b[1];
- y.b[3] = x.b[0];
- *v = y.w;
- }
- /** Convert status word from little endian to native and vice versa **/
- static void fix_endianess(uint32_t h[16], unsigned start, unsigned end)
- {
- unsigned i;
- if (littleEndian())
- return;
- for (i=start; i<end; i++)
- byteSwap(&h[i]);
- }
- static unsigned minAB(unsigned a, unsigned b) {
- return a < b ? a : b;
- }
- #define ROTL(q, n) (((q) << (n)) | ((q) >> (32 - (n))))
- #define QR(a, b, c, d) {\
- a+=b; d^=a; d=ROTL(d,16); \
- c+=d; b^=c; b=ROTL(b,12); \
- a+=b; d^=a; d=ROTL(d,8); \
- c+=d; b^=c; b=ROTL(b,7); \
- }
- EXPORT_SYM int chacha20_init(stream_state **pState,
- const uint8_t *key,
- size_t keySize,
- const uint8_t *nonce,
- size_t nonceSize)
- {
- stream_state *hs;
- if (NULL == pState || NULL == nonce)
- return ERR_NULL;
- if (NULL == key || keySize != KEY_SIZE)
- return ERR_KEY_SIZE;
- if (NULL == nonce || nonceSize != NONCE_SIZE)
- return ERR_NONCE_SIZE;
- *pState = hs = (stream_state*) calloc(1, sizeof(stream_state));
- if (NULL == hs)
- return ERR_MEMORY;
- hs->h[0] = 0x61707865;
- hs->h[1] = 0x3320646e;
- hs->h[2] = 0x79622d32;
- hs->h[3] = 0x6b206574;
- memcpy(&hs->h[4], key, KEY_SIZE);
- fix_endianess(hs->h, 4, 12);
- memcpy(&hs->h[14], nonce, NONCE_SIZE);
- fix_endianess(hs->h, 14, 16);
- hs->usedKeyStream = sizeof hs->keyStream;
- return 0;
- }
- EXPORT_SYM int chacha20_destroy(stream_state *state)
- {
- if (NULL == state)
- return ERR_NULL;
- free(state);
- return 0;
- }
- static int chacha20_core(stream_state *state)
- {
- unsigned i;
- uint32_t h[16];
- memcpy(h, state->h, sizeof h);
- for (i=0; i<10; i++) {
- /** Column round **/
- QR(h[0], h[4], h[ 8], h[12]);
- QR(h[1], h[5], h[ 9], h[13]);
- QR(h[2], h[6], h[10], h[14]);
- QR(h[3], h[7], h[11], h[15]);
- /** Diagonal round **/
- QR(h[0], h[5], h[10], h[15]);
- QR(h[1], h[6], h[11], h[12]);
- QR(h[2], h[7], h[ 8], h[13]);
- QR(h[3], h[4], h[ 9], h[14]);
- }
- for (i=0; i<16; i++)
- h[i] += state->h[i];
- fix_endianess(h, 0, 16);
- memcpy(state->keyStream, h, sizeof h);
- state->usedKeyStream = 0;
- if (++state->h[12] == 0) {
- if (++state->h[13] == 0) {
- return ERR_MAX_DATA;
- }
- }
- return 0;
- }
- EXPORT_SYM int chacha20_encrypt(stream_state *state,
- const uint8_t in[],
- uint8_t out[],
- size_t len)
- {
- if (NULL == state || NULL == in || NULL == out)
- return ERR_NULL;
- while (len>0) {
- unsigned keyStreamToUse;
- unsigned i;
- if (state->usedKeyStream == sizeof state->keyStream) {
- int result;
- result = chacha20_core(state);
- if (result)
- return result;
- }
- keyStreamToUse = minAB(len, sizeof state->keyStream - state->usedKeyStream);
- for (i=0; i<keyStreamToUse; i++)
- *out++ = *in++ ^ state->keyStream[i + state->usedKeyStream];
- len -= keyStreamToUse;
- state->usedKeyStream += keyStreamToUse;
- }
- return 0;
- }
- EXPORT_SYM int chacha20_seek(stream_state *state,
- unsigned long block_high,
- unsigned long block_low,
- unsigned offset)
- {
- int result;
- if (NULL == state)
- return ERR_NULL;
- if (offset >= sizeof state->keyStream)
- return ERR_MAX_OFFSET;
- state->h[12] = block_low;
- state->h[13] = block_high;
- result = chacha20_core(state);
- if (result)
- return result;
- state->usedKeyStream = offset;
- return 0;
- }
|