diff options
Diffstat (limited to 'thirdparty/nRF5_SDK_15.0.0_a53641a/external/cifra_AES128-EAX/cifra_cmac.c')
-rw-r--r-- | thirdparty/nRF5_SDK_15.0.0_a53641a/external/cifra_AES128-EAX/cifra_cmac.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/thirdparty/nRF5_SDK_15.0.0_a53641a/external/cifra_AES128-EAX/cifra_cmac.c b/thirdparty/nRF5_SDK_15.0.0_a53641a/external/cifra_AES128-EAX/cifra_cmac.c new file mode 100644 index 0000000..51f5843 --- /dev/null +++ b/thirdparty/nRF5_SDK_15.0.0_a53641a/external/cifra_AES128-EAX/cifra_cmac.c @@ -0,0 +1,150 @@ +/* + * cifra - embedded cryptography library + * Written in 2014 by Joseph Birr-Pixton <jpixton@gmail.com> + * + * To the extent possible under law, the author(s) have dedicated all + * copyright and related and 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 + * <http://creativecommons.org/publicdomain/zero/1.0/>. + */ + +#include "handy.h" +#include "prp.h" +#include "modes.h" +#include "bitops.h" +#include "blockwise.h" +#include "gf128.h" +#include "tassert.h" + +#include <string.h> + +void cf_cmac_init(cf_cmac *ctx, const cf_prp *prp, void *prpctx) +{ + uint8_t L[CF_MAXBLOCK]; + assert(prp->blocksz == 16); + + mem_clean(ctx, sizeof *ctx); + + /* L = E_K(0^n) */ + mem_clean(L, prp->blocksz); + prp->encrypt(prpctx, L, L); + + /* B = 2L */ + cf_gf128 gf; + cf_gf128_frombytes_be(L, gf); + cf_gf128_double(gf, gf); + cf_gf128_tobytes_be(gf, ctx->B); + + /* P = 4L */ + cf_gf128_double(gf, gf); + cf_gf128_tobytes_be(gf, ctx->P); + + ctx->prp = prp; + ctx->prpctx = prpctx; +} + +void cf_cmac_sign(cf_cmac *ctx, const uint8_t *data, size_t len, uint8_t out[CF_MAXBLOCK]) +{ + cf_cmac_stream stream; + stream.cmac = *ctx; + cf_cmac_stream_reset(&stream); + cf_cmac_stream_update(&stream, data, len, 1); + cf_cmac_stream_final(&stream, out); +} + +void cf_cmac_stream_init(cf_cmac_stream *ctx, const cf_prp *prp, void *prpctx) +{ + cf_cmac_init(&ctx->cmac, prp, prpctx); + cf_cmac_stream_reset(ctx); +} + +void cf_cmac_stream_reset(cf_cmac_stream *ctx) +{ + uint8_t iv_zero[CF_MAXBLOCK] = { 0 }; + cf_cbc_init(&ctx->cbc, ctx->cmac.prp, ctx->cmac.prpctx, iv_zero); + mem_clean(ctx->buffer, sizeof ctx->buffer); + ctx->used = 0; + ctx->processed = 0; + ctx->finalised = 0; +} + +static void cmac_process(void *vctx, const uint8_t *block) +{ + cf_cmac_stream *ctx = vctx; + uint8_t output[CF_MAXBLOCK]; + cf_cbc_encrypt(&ctx->cbc, block, output, 1); + ctx->processed += ctx->cmac.prp->blocksz; +} + +static void cmac_process_final(cf_cmac_stream *ctx, const uint8_t *block, + const uint8_t *xor) +{ + uint8_t input[CF_MAXBLOCK]; + uint8_t output[CF_MAXBLOCK]; + xor_bb(input, block, xor, ctx->cmac.prp->blocksz); + cf_cbc_encrypt(&ctx->cbc, input, output, 1); + ctx->processed += ctx->cmac.prp->blocksz; + /* signature is in ctx->cbc.block. */ +} + +static void cmac_process_final_nopad(void *vctx, const uint8_t *block) +{ + cf_cmac_stream *ctx = vctx; + cmac_process_final(ctx, block, ctx->cmac.B); + ctx->finalised = 1; +} + +static void cmac_process_final_pad(void *vctx, const uint8_t *block) +{ + cf_cmac_stream *ctx = vctx; + cmac_process_final(ctx, block, ctx->cmac.P); + ctx->finalised = 1; +} + +void cf_cmac_stream_update(cf_cmac_stream *ctx, const uint8_t *data, size_t len, int isfinal) +{ + size_t blocksz = ctx->cmac.prp->blocksz; + cf_blockwise_in_fn final_fn = cmac_process; + int needpad = 0; + + if (isfinal) + { + int whole_number_of_blocks = ((len + ctx->used) & 0xf) == 0; + int empty_message = len == 0 && ctx->used == 0 && ctx->processed == 0; + + assert(!ctx->finalised); /* finalised before? */ + assert(len != 0 || empty_message); /* we can't be told we're done after the fact. */ + + /* If we have a whole number of blocks, and at least 1 block, we XOR in B. + * Otherwise, we need to pad and XOR in P. */ + if (whole_number_of_blocks && !empty_message) + final_fn = cmac_process_final_nopad; + else + needpad = 1; + } + + /* Input data */ + cf_blockwise_accumulate_final(ctx->buffer, &ctx->used, blocksz, + data, len, + cmac_process, + final_fn, ctx); + + /* Input padding */ + if (needpad) + { + cf_blockwise_acc_pad(ctx->buffer, &ctx->used, blocksz, + 0x80, 0x00, 0x00, blocksz - ctx->used, + cmac_process_final_pad, ctx); + } +} + +void cf_cmac_stream_final(cf_cmac_stream *ctx, uint8_t out[CF_MAXBLOCK]) +{ + assert(ctx->finalised); + memcpy(out, ctx->cbc.block, ctx->cmac.prp->blocksz); +} + |