diff options
Diffstat (limited to 'third_party/bearssl/src/aes_ct_cbcdec.c')
| -rw-r--r-- | third_party/bearssl/src/aes_ct_cbcdec.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/third_party/bearssl/src/aes_ct_cbcdec.c b/third_party/bearssl/src/aes_ct_cbcdec.c new file mode 100644 index 0000000..522645a --- /dev/null +++ b/third_party/bearssl/src/aes_ct_cbcdec.c @@ -0,0 +1,111 @@ +/* + * 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_cbcdec_init(br_aes_ct_cbcdec_keys *ctx, + const void *key, size_t len) +{ + ctx->vtable = &br_aes_ct_cbcdec_vtable; + ctx->num_rounds = br_aes_ct_keysched(ctx->skey, key, len); +} + +/* see bearssl_block.h */ +void +br_aes_ct_cbcdec_run(const br_aes_ct_cbcdec_keys *ctx, + void *iv, void *data, size_t len) +{ + unsigned char *buf, *ivbuf; + uint32_t iv0, iv1, iv2, iv3; + 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); + iv3 = br_dec32le(ivbuf + 12); + buf = data; + while (len > 0) { + uint32_t q[8], sq[8]; + + q[0] = br_dec32le(buf); + q[2] = br_dec32le(buf + 4); + q[4] = br_dec32le(buf + 8); + q[6] = br_dec32le(buf + 12); + if (len >= 32) { + q[1] = br_dec32le(buf + 16); + q[3] = br_dec32le(buf + 20); + q[5] = br_dec32le(buf + 24); + q[7] = br_dec32le(buf + 28); + } else { + q[1] = 0; + q[3] = 0; + q[5] = 0; + q[7] = 0; + } + memcpy(sq, q, sizeof q); + br_aes_ct_ortho(q); + br_aes_ct_bitslice_decrypt(ctx->num_rounds, sk_exp, q); + br_aes_ct_ortho(q); + br_enc32le(buf, q[0] ^ iv0); + br_enc32le(buf + 4, q[2] ^ iv1); + br_enc32le(buf + 8, q[4] ^ iv2); + br_enc32le(buf + 12, q[6] ^ iv3); + if (len < 32) { + iv0 = sq[0]; + iv1 = sq[2]; + iv2 = sq[4]; + iv3 = sq[6]; + break; + } + br_enc32le(buf + 16, q[1] ^ sq[0]); + br_enc32le(buf + 20, q[3] ^ sq[2]); + br_enc32le(buf + 24, q[5] ^ sq[4]); + br_enc32le(buf + 28, q[7] ^ sq[6]); + iv0 = sq[1]; + iv1 = sq[3]; + iv2 = sq[5]; + iv3 = sq[7]; + buf += 32; + len -= 32; + } + br_enc32le(ivbuf, iv0); + br_enc32le(ivbuf + 4, iv1); + br_enc32le(ivbuf + 8, iv2); + br_enc32le(ivbuf + 12, iv3); +} + +/* see bearssl_block.h */ +const br_block_cbcdec_class br_aes_ct_cbcdec_vtable = { + sizeof(br_aes_ct_cbcdec_keys), + 16, + 4, + (void (*)(const br_block_cbcdec_class **, const void *, size_t)) + &br_aes_ct_cbcdec_init, + (void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t)) + &br_aes_ct_cbcdec_run +}; |