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/* MIT License
*
* Copyright (c) 2016-2020 INRIA, CMU and Microsoft Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "internal/Hacl_Chacha20.h"
const uint32_t
Hacl_Impl_Chacha20_Vec_chacha20_constants[4U] = { (uint32_t)0x61707865U, (uint32_t)0x3320646eU, (uint32_t)0x79622d32U, (uint32_t)0x6b206574U };
static inline void
quarter_round(uint32_t *st, uint32_t a, uint32_t b, uint32_t c, uint32_t d)
{
uint32_t sta = st[a];
uint32_t stb0 = st[b];
uint32_t std0 = st[d];
uint32_t sta10 = sta + stb0;
uint32_t std10 = std0 ^ sta10;
uint32_t std2 = std10 << (uint32_t)16U | std10 >> (uint32_t)16U;
st[a] = sta10;
st[d] = std2;
uint32_t sta0 = st[c];
uint32_t stb1 = st[d];
uint32_t std3 = st[b];
uint32_t sta11 = sta0 + stb1;
uint32_t std11 = std3 ^ sta11;
uint32_t std20 = std11 << (uint32_t)12U | std11 >> (uint32_t)20U;
st[c] = sta11;
st[b] = std20;
uint32_t sta2 = st[a];
uint32_t stb2 = st[b];
uint32_t std4 = st[d];
uint32_t sta12 = sta2 + stb2;
uint32_t std12 = std4 ^ sta12;
uint32_t std21 = std12 << (uint32_t)8U | std12 >> (uint32_t)24U;
st[a] = sta12;
st[d] = std21;
uint32_t sta3 = st[c];
uint32_t stb = st[d];
uint32_t std = st[b];
uint32_t sta1 = sta3 + stb;
uint32_t std1 = std ^ sta1;
uint32_t std22 = std1 << (uint32_t)7U | std1 >> (uint32_t)25U;
st[c] = sta1;
st[b] = std22;
}
static inline void
double_round(uint32_t *st)
{
quarter_round(st, (uint32_t)0U, (uint32_t)4U, (uint32_t)8U, (uint32_t)12U);
quarter_round(st, (uint32_t)1U, (uint32_t)5U, (uint32_t)9U, (uint32_t)13U);
quarter_round(st, (uint32_t)2U, (uint32_t)6U, (uint32_t)10U, (uint32_t)14U);
quarter_round(st, (uint32_t)3U, (uint32_t)7U, (uint32_t)11U, (uint32_t)15U);
quarter_round(st, (uint32_t)0U, (uint32_t)5U, (uint32_t)10U, (uint32_t)15U);
quarter_round(st, (uint32_t)1U, (uint32_t)6U, (uint32_t)11U, (uint32_t)12U);
quarter_round(st, (uint32_t)2U, (uint32_t)7U, (uint32_t)8U, (uint32_t)13U);
quarter_round(st, (uint32_t)3U, (uint32_t)4U, (uint32_t)9U, (uint32_t)14U);
}
static inline void
rounds(uint32_t *st)
{
double_round(st);
double_round(st);
double_round(st);
double_round(st);
double_round(st);
double_round(st);
double_round(st);
double_round(st);
double_round(st);
double_round(st);
}
static inline void
chacha20_core(uint32_t *k, uint32_t *ctx, uint32_t ctr)
{
memcpy(k, ctx, (uint32_t)16U * sizeof(uint32_t));
uint32_t ctr_u32 = ctr;
k[12U] = k[12U] + ctr_u32;
rounds(k);
KRML_MAYBE_FOR16(i,
(uint32_t)0U,
(uint32_t)16U,
(uint32_t)1U,
uint32_t *os = k;
uint32_t x = k[i] + ctx[i];
os[i] = x;);
k[12U] = k[12U] + ctr_u32;
}
static const uint32_t
chacha20_constants[4U] = { (uint32_t)0x61707865U, (uint32_t)0x3320646eU, (uint32_t)0x79622d32U, (uint32_t)0x6b206574U };
void
Hacl_Impl_Chacha20_chacha20_init(uint32_t *ctx, uint8_t *k, uint8_t *n, uint32_t ctr)
{
KRML_MAYBE_FOR4(i,
(uint32_t)0U,
(uint32_t)4U,
(uint32_t)1U,
uint32_t *os = ctx;
uint32_t x = chacha20_constants[i];
os[i] = x;);
KRML_MAYBE_FOR8(i,
(uint32_t)0U,
(uint32_t)8U,
(uint32_t)1U,
uint32_t *os = ctx + (uint32_t)4U;
uint8_t *bj = k + i * (uint32_t)4U;
uint32_t u = load32_le(bj);
uint32_t r = u;
uint32_t x = r;
os[i] = x;);
ctx[12U] = ctr;
KRML_MAYBE_FOR3(i,
(uint32_t)0U,
(uint32_t)3U,
(uint32_t)1U,
uint32_t *os = ctx + (uint32_t)13U;
uint8_t *bj = n + i * (uint32_t)4U;
uint32_t u = load32_le(bj);
uint32_t r = u;
uint32_t x = r;
os[i] = x;);
}
static void
chacha20_encrypt_block(uint32_t *ctx, uint8_t *out, uint32_t incr, uint8_t *text)
{
uint32_t k[16U] = { 0U };
chacha20_core(k, ctx, incr);
uint32_t bl[16U] = { 0U };
KRML_MAYBE_FOR16(i,
(uint32_t)0U,
(uint32_t)16U,
(uint32_t)1U,
uint32_t *os = bl;
uint8_t *bj = text + i * (uint32_t)4U;
uint32_t u = load32_le(bj);
uint32_t r = u;
uint32_t x = r;
os[i] = x;);
KRML_MAYBE_FOR16(i,
(uint32_t)0U,
(uint32_t)16U,
(uint32_t)1U,
uint32_t *os = bl;
uint32_t x = bl[i] ^ k[i];
os[i] = x;);
KRML_MAYBE_FOR16(i,
(uint32_t)0U,
(uint32_t)16U,
(uint32_t)1U,
store32_le(out + i * (uint32_t)4U, bl[i]););
}
static inline void
chacha20_encrypt_last(uint32_t *ctx, uint32_t len, uint8_t *out, uint32_t incr, uint8_t *text)
{
uint8_t plain[64U] = { 0U };
memcpy(plain, text, len * sizeof(uint8_t));
chacha20_encrypt_block(ctx, plain, incr, plain);
memcpy(out, plain, len * sizeof(uint8_t));
}
void
Hacl_Impl_Chacha20_chacha20_update(uint32_t *ctx, uint32_t len, uint8_t *out, uint8_t *text)
{
uint32_t rem = len % (uint32_t)64U;
uint32_t nb = len / (uint32_t)64U;
uint32_t rem1 = len % (uint32_t)64U;
for (uint32_t i = (uint32_t)0U; i < nb; i++) {
chacha20_encrypt_block(ctx, out + i * (uint32_t)64U, i, text + i * (uint32_t)64U);
}
if (rem1 > (uint32_t)0U) {
chacha20_encrypt_last(ctx, rem, out + nb * (uint32_t)64U, nb, text + nb * (uint32_t)64U);
}
}
void
Hacl_Chacha20_chacha20_encrypt(
uint32_t len,
uint8_t *out,
uint8_t *text,
uint8_t *key,
uint8_t *n,
uint32_t ctr)
{
uint32_t ctx[16U] = { 0U };
Hacl_Impl_Chacha20_chacha20_init(ctx, key, n, ctr);
Hacl_Impl_Chacha20_chacha20_update(ctx, len, out, text);
}
void
Hacl_Chacha20_chacha20_decrypt(
uint32_t len,
uint8_t *out,
uint8_t *cipher,
uint8_t *key,
uint8_t *n,
uint32_t ctr)
{
uint32_t ctx[16U] = { 0U };
Hacl_Impl_Chacha20_chacha20_init(ctx, key, n, ctr);
Hacl_Impl_Chacha20_chacha20_update(ctx, len, out, cipher);
}
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