diff options
Diffstat (limited to 'src/3p/monocypher/monocypher-rng.c')
| -rw-r--r-- | src/3p/monocypher/monocypher-rng.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/src/3p/monocypher/monocypher-rng.c b/src/3p/monocypher/monocypher-rng.c new file mode 100644 index 0000000..d59fc76 --- /dev/null +++ b/src/3p/monocypher/monocypher-rng.c @@ -0,0 +1,97 @@ +// This file is dual-licensed. Choose whichever licence you want from +// the two licences listed below. +// +// The first licence is a regular 2-clause BSD licence. The second licence +// is the CC-0 from Creative Commons. It is intended to release Monocypher +// to the public domain. The BSD licence serves as a fallback option. +// +// SPDX-License-Identifier: BSD-2-Clause OR CC0-1.0 +// +// ------------------------------------------------------------------------ +// +// Copyright (c) 2019-2021, Loup Vaillant +// 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. +// +// ------------------------------------------------------------------------ +// +// Written in 2019-2021 by Loup Vaillant +// +// To the extent possible under law, the author(s) have dedicated all copyright +// and related neighboring rights to this software to the public domain +// worldwide. This software is distributed without any warranty. +// +// You should have received a copy of the CC0 Public Domain Dedication along +// with this software. If not, see +// <https://creativecommons.org/publicdomain/zero/1.0/> + +#include "monocypher-rng.h" +#include "monocypher.h" + +// avoid memcpy dependency (the compiler will likely use memcpy anyway) +static void copy(uint8_t *out, uint8_t *in, size_t size) +{ + for (size_t i = 0; i < size; i++) { + out[i] = in[i]; + } +} + +// mike: HACK: for single translation unit crypto.c, there's already zero[128] +// in monocypher.c, so leave this out! +//static const uint8_t zero[8] = {0}; + +void crypto_rng_init(crypto_rng_ctx *ctx, uint8_t random_seed[32]) +{ + copy(ctx->pool, random_seed, 32); + ctx->idx = 512; + crypto_wipe(random_seed, 32); +} + +void crypto_rng_read(crypto_rng_ctx *ctx, uint8_t *buf, size_t size) +{ + size_t pool_size = 512 - ctx->idx; + while (size > pool_size) { + copy(buf, ctx->pool + ctx->idx, pool_size); + crypto_chacha20(ctx->pool, 0, 512, ctx->pool, zero); + size -= pool_size; + buf += pool_size; + ctx->idx = 32; + pool_size = 512 - 32; + } + copy(buf, ctx->pool + ctx->idx, size); + ctx->idx += size; + + // Wipe used bytes ASAP (even if they'll be erased later) + crypto_wipe(ctx->pool + 32, ctx->idx - 32); +} + +void crypto_rng_fork(crypto_rng_ctx *ctx, crypto_rng_ctx *child_ctx) +{ + uint8_t child_seed[32]; // wiped by crypto_rng_init; + crypto_rng_read(ctx, child_seed, 32); + crypto_rng_init(child_ctx, child_seed); +} |