From 8fe93b8e1d1d968bdf0b8a35335b060d92a9d7d7 Mon Sep 17 00:00:00 2001 From: joe Date: Sat, 8 Jul 2017 22:10:40 -0400 Subject: WIP: Tox encryption. --- cbits/cryptonite_xsalsa.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 cbits/cryptonite_xsalsa.c (limited to 'cbits/cryptonite_xsalsa.c') diff --git a/cbits/cryptonite_xsalsa.c b/cbits/cryptonite_xsalsa.c new file mode 100644 index 00000000..6718cd7d --- /dev/null +++ b/cbits/cryptonite_xsalsa.c @@ -0,0 +1,80 @@ +/* + * Copyright (c) 2016 Brandon Hamilton + * + * 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 the author nor the names of his contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 AUTHORS 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 +#include +#include "cryptonite_xsalsa.h" +#include "cryptonite_bitfn.h" + +static inline uint32_t load32(const uint8_t *p) +{ + return le32_to_cpu(*((uint32_t *) p)); +} + +/* XSalsa20 algorithm as described in https://cr.yp.to/snuffle/xsalsa-20081128.pdf */ +void cryptonite_xsalsa_init(cryptonite_salsa_context *ctx, uint8_t nb_rounds, + uint32_t keylen, const uint8_t *key, + uint32_t ivlen, const uint8_t *iv) +{ + memset(ctx, 0, sizeof(*ctx)); + ctx->nb_rounds = nb_rounds; + + /* Create initial 512-bit input block: + (x0, x5, x10, x15) is the Salsa20 constant + (x1, x2, x3, x4, x11, x12, x13, x14) is a 256-bit key + (x6, x7, x8, x9) is the first 128 bits of a 192-bit nonce + */ + cryptonite_salsa_init_core(&ctx->st, keylen, key, 8, iv); + ctx->st.d[ 8] = load32(iv + 8); + ctx->st.d[ 9] = load32(iv + 12); + + /* Compute (z0, z1, . . . , z15) = doubleround ^(r/2) (x0, x1, . . . , x15) */ + block hSalsa; + memset(&hSalsa, 0, sizeof(block)); + cryptonite_salsa_core_xor(nb_rounds, &hSalsa, &ctx->st); + + /* Build a new 512-bit input block (x′0, x′1, . . . , x′15): + (x′0, x′5, x′10, x′15) is the Salsa20 constant + (x′1,x′2,x′3,x′4,x′11,x′12,x′13,x′14) = (z0,z5,z10,z15,z6,z7,z8,z9) + (x′6,x′7) is the last 64 bits of the 192-bit nonce + (x′8, x′9) is a 64-bit block counter. + */ + ctx->st.d[ 1] = hSalsa.d[ 0] - ctx->st.d[ 0]; + ctx->st.d[ 2] = hSalsa.d[ 5] - ctx->st.d[ 5]; + ctx->st.d[ 3] = hSalsa.d[10] - ctx->st.d[10]; + ctx->st.d[ 4] = hSalsa.d[15] - ctx->st.d[15]; + ctx->st.d[11] = hSalsa.d[ 6] - ctx->st.d[ 6]; + ctx->st.d[12] = hSalsa.d[ 7] - ctx->st.d[ 7]; + ctx->st.d[13] = hSalsa.d[ 8] - ctx->st.d[ 8]; + ctx->st.d[14] = hSalsa.d[ 9] - ctx->st.d[ 9]; + ctx->st.d[ 6] = load32(iv + 16); + ctx->st.d[ 7] = load32(iv + 20); + ctx->st.d[ 8] = 0; + ctx->st.d[ 9] = 0; +} \ No newline at end of file -- cgit v1.2.3