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Added generic EAX and CCM implementations.

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This commit is contained in:
Thomas Pornin 2017-10-23 23:27:28 +02:00
parent 8e94ad2fcb
commit dddc412922
14 changed files with 4530 additions and 13 deletions
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28
src/aead/gcm.c
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@ -56,6 +56,7 @@ br_gcm_init(br_gcm_context *ctx, const br_block_ctr_class **bctx, br_ghash gh)
{
unsigned char iv[12];
ctx->vtable = &br_gcm_vtable;
ctx->bctx = bctx;
ctx->gh = gh;
@ -262,9 +263,19 @@ br_gcm_get_tag(br_gcm_context *ctx, void *tag)
(*ctx->bctx)->run(ctx->bctx, ctx->j0_1, ctx->j0_2, tag, 16);
}
/* see bearssl_aead.h */
void
br_gcm_get_tag_trunc(br_gcm_context *ctx, void *tag, size_t len)
{
unsigned char tmp[16];
br_gcm_get_tag(ctx, tmp);
memcpy(tag, tmp, len);
}
/* see bearssl_aead.h */
uint32_t
br_gcm_check_tag(br_gcm_context *ctx, const void *tag)
br_gcm_check_tag_trunc(br_gcm_context *ctx, const void *tag, size_t len)
{
unsigned char tmp[16];
size_t u;
@ -272,12 +283,19 @@ br_gcm_check_tag(br_gcm_context *ctx, const void *tag)
br_gcm_get_tag(ctx, tmp);
x = 0;
for (u = 0; u < sizeof tmp; u ++) {
for (u = 0; u < len; u ++) {
x |= tmp[u] ^ ((const unsigned char *)tag)[u];
}
return EQ0(x);
}
/* see bearssl_aead.h */
uint32_t
br_gcm_check_tag(br_gcm_context *ctx, const void *tag)
{
return br_gcm_check_tag_trunc(ctx, tag, 16);
}
/* see bearssl_aead.h */
const br_aead_class br_gcm_vtable = {
16,
@ -292,5 +310,9 @@ const br_aead_class br_gcm_vtable = {
(void (*)(const br_aead_class **, void *))
&br_gcm_get_tag,
(uint32_t (*)(const br_aead_class **, const void *))
&br_gcm_check_tag
&br_gcm_check_tag,
(void (*)(const br_aead_class **, void *, size_t))
&br_gcm_get_tag_trunc,
(uint32_t (*)(const br_aead_class **, const void *, size_t))
&br_gcm_check_tag_trunc
};