diff options
Diffstat (limited to 'third_party/bearssl/src/aes_ct_ctr.c')
| -rw-r--r-- | third_party/bearssl/src/aes_ct_ctr.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/third_party/bearssl/src/aes_ct_ctr.c b/third_party/bearssl/src/aes_ct_ctr.c new file mode 100644 index 0000000..f407689 --- /dev/null +++ b/third_party/bearssl/src/aes_ct_ctr.c @@ -0,0 +1,116 @@ +/* + * Copyright (c) 2016 Thomas Pornin <[email protected]> + * + * 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 "inner.h" + +/* see bearssl_block.h */ +void +br_aes_ct_ctr_init(br_aes_ct_ctr_keys *ctx, + const void *key, size_t len) +{ + ctx->vtable = &br_aes_ct_ctr_vtable; + ctx->num_rounds = br_aes_ct_keysched(ctx->skey, key, len); +} + +static void +xorbuf(void *dst, const void *src, size_t len) +{ + unsigned char *d; + const unsigned char *s; + + d = dst; + s = src; + while (len -- > 0) { + *d ++ ^= *s ++; + } +} + +/* see bearssl_block.h */ +uint32_t +br_aes_ct_ctr_run(const br_aes_ct_ctr_keys *ctx, + const void *iv, uint32_t cc, void *data, size_t len) +{ + unsigned char *buf; + const unsigned char *ivbuf; + uint32_t iv0, iv1, iv2; + uint32_t sk_exp[120]; + + br_aes_ct_skey_expand(sk_exp, ctx->num_rounds, ctx->skey); + ivbuf = iv; + iv0 = br_dec32le(ivbuf); + iv1 = br_dec32le(ivbuf + 4); + iv2 = br_dec32le(ivbuf + 8); + buf = data; + while (len > 0) { + uint32_t q[8]; + unsigned char tmp[32]; + + /* + * TODO: see if we can save on the first br_aes_ct_ortho() + * call, since iv0/iv1/iv2 are constant for the whole run. + */ + q[0] = q[1] = iv0; + q[2] = q[3] = iv1; + q[4] = q[5] = iv2; + q[6] = br_swap32(cc); + q[7] = br_swap32(cc + 1); + br_aes_ct_ortho(q); + br_aes_ct_bitslice_encrypt(ctx->num_rounds, sk_exp, q); + br_aes_ct_ortho(q); + br_enc32le(tmp, q[0]); + br_enc32le(tmp + 4, q[2]); + br_enc32le(tmp + 8, q[4]); + br_enc32le(tmp + 12, q[6]); + br_enc32le(tmp + 16, q[1]); + br_enc32le(tmp + 20, q[3]); + br_enc32le(tmp + 24, q[5]); + br_enc32le(tmp + 28, q[7]); + + if (len <= 32) { + xorbuf(buf, tmp, len); + cc ++; + if (len > 16) { + cc ++; + } + break; + } + xorbuf(buf, tmp, 32); + buf += 32; + len -= 32; + cc += 2; + } + return cc; +} + +/* see bearssl_block.h */ +const br_block_ctr_class br_aes_ct_ctr_vtable = { + sizeof(br_aes_ct_ctr_keys), + 16, + 4, + (void (*)(const br_block_ctr_class **, const void *, size_t)) + &br_aes_ct_ctr_init, + (uint32_t (*)(const br_block_ctr_class *const *, + const void *, uint32_t, void *, size_t)) + &br_aes_ct_ctr_run +}; |