diff options
Diffstat (limited to 'src/crypto/mac/ghash/builtin/ghash_builtin.c')
| -rw-r--r-- | src/crypto/mac/ghash/builtin/ghash_builtin.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/src/crypto/mac/ghash/builtin/ghash_builtin.c b/src/crypto/mac/ghash/builtin/ghash_builtin.c index 28e9292..0b957a4 100644 --- a/src/crypto/mac/ghash/builtin/ghash_builtin.c +++ b/src/crypto/mac/ghash/builtin/ghash_builtin.c @@ -23,18 +23,27 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ +/** + \file + + Portable, table-based GHASH implementation +*/ + #include "../../../../crypto.h" +/** MAC state used by this GHASH implmentation */ struct fastd_mac_state { - fastd_block128_t H[32][16]; + fastd_block128_t H[32][16]; /**< Lookup table unpacked from the hash key */ }; +/** Lower 128 bit of the modulus \f$ x^{128} + x^7 + x^2 + x + 1 \f$ */ static const fastd_block128_t r = { .b = {0xe1} }; +/** Right shift of a 128bit integer by up to 8 bytes */ static inline uint8_t shr(fastd_block128_t *out, const fastd_block128_t *in, int n) { size_t i; uint8_t c = 0; @@ -48,6 +57,7 @@ static inline uint8_t shr(fastd_block128_t *out, const fastd_block128_t *in, int return (c >> (8-n)); } +/** Galois field multiplication of a 128bit integer with H */ static inline void mulH_a(fastd_block128_t *x, const fastd_mac_state_t *cstate) { fastd_block128_t out = {}; @@ -61,6 +71,7 @@ static inline void mulH_a(fastd_block128_t *x, const fastd_mac_state_t *cstate) } +/** Initializes the MAC state with the unpacked key data */ static fastd_mac_state_t* ghash_init(const uint8_t *key) { fastd_mac_state_t *state; if (posix_memalign((void**)&state, 16, sizeof(fastd_mac_state_t))) @@ -107,6 +118,7 @@ static fastd_mac_state_t* ghash_init(const uint8_t *key) { return state; } +/** Calculates the GHASH of the supplied blocks */ static bool ghash_hash(const fastd_mac_state_t *state, fastd_block128_t *out, const fastd_block128_t *in, size_t n_blocks) { memset(out, 0, sizeof(fastd_block128_t)); @@ -119,6 +131,7 @@ static bool ghash_hash(const fastd_mac_state_t *state, fastd_block128_t *out, co return true; } +/** Frees the MAC state */ static void ghash_free(fastd_mac_state_t *state) { if (state) { secure_memzero(state, sizeof(*state)); @@ -126,6 +139,7 @@ static void ghash_free(fastd_mac_state_t *state) { } } +/** The builtin GHASH implementation */ const fastd_mac_t fastd_mac_ghash_builtin = { .init = ghash_init, .hash = ghash_hash, |