diff options
Diffstat (limited to 'sys/dev/random/chacha20.c')
-rw-r--r-- | sys/dev/random/chacha20.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/sys/dev/random/chacha20.c b/sys/dev/random/chacha20.c new file mode 100644 index 0000000..41f823c --- /dev/null +++ b/sys/dev/random/chacha20.c @@ -0,0 +1,97 @@ +/* + * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team. + * 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. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * 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 OWNER 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 <dev/random/chacha20.h> + +static const char sigma[16] = "expand 32-byte k"; + +void chacha20_init(uint32_t state[16], const uint8_t key[32], + const uint8_t nonce[12], uint32_t counter) +{ + state[0] = ((uint32_t *)sigma)[0]; + state[1] = ((uint32_t *)sigma)[1]; + state[2] = ((uint32_t *)sigma)[2]; + state[3] = ((uint32_t *)sigma)[3]; + + for (int i = 0; i < 8; ++i) { + state[4 + i] = ((uint32_t *)key)[i]; + } + + state[12] = counter; + state[13] = ((uint32_t *)nonce)[0]; + state[14] = ((uint32_t *)nonce)[1]; + state[15] = ((uint32_t *)nonce)[2]; +} + +void +chacha20_block(uint32_t state[16], uint8_t out[64]) +{ + uint32_t x[16]; + memcpy(x, state, sizeof(x)); + + for (int i = 0; i < 10; i++) { + + QR(x[0], x[4], x[8], x[12]); + QR(x[1], x[5], x[9], x[13]); + QR(x[2], x[6], x[10], x[14]); + QR(x[3], x[7], x[11], x[15]); + + QR(x[0], x[5], x[10], x[15]); + QR(x[1], x[6], x[11], x[12]); + QR(x[2], x[7], x[8], x[13]); + QR(x[3], x[4], x[9], x[14]); + } + + for (int i = 0; i < 16; ++i) { + x[i] += state[i]; + ((uint32_t *)out)[i] = x[i]; + } + + state[12]++; +} + +void +chacha20_encrypt(uint32_t state[16], uint8_t *in, + uint8_t *out, size_t len) +{ + uint8_t block[64]; + size_t offset = 0; + + while (len > 0) { + chacha20_block(state, block); + size_t n = len > 64 ? 64 : len; + + for (size_t i = 0; i < n; ++i) { + out[offset + i] = in ? in[offset + i] ^ block[i] : block[i]; + } + + offset += n; + len -= n; + } +} |