diff options
Diffstat (limited to 'src/sha256.c')
| -rw-r--r-- | src/sha256.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/src/sha256.c b/src/sha256.c index 38bc43d..c05adbc 100644 --- a/src/sha256.c +++ b/src/sha256.c @@ -23,6 +23,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ +/** + \file sha256.c + + Small SHA256 and HMAC-SHA256 implementation +*/ + #include "sha256.h" @@ -32,10 +38,16 @@ #include <arpa/inet.h> +/** right-rotation of a 32bit value */ static inline uint32_t rotr(uint32_t x, int r) { return (x >> r) | (x << (32-r)); } +/** + Copies a (potentially incomplete) input block, while switching from big endian to CPU byte order + + After the last byte, a one-bit is added, as SHA256 defines. +*/ static inline void copy_words(uint32_t w[8], const uint32_t *in, ssize_t *left) { size_t i; for (i = 0; i < 8; i++) { @@ -58,6 +70,7 @@ static inline void copy_words(uint32_t w[8], const uint32_t *in, ssize_t *left) } } +/** Hashes a list of input blocks */ static void sha256_list(uint32_t out[FASTD_SHA256_HASH_WORDS], const uint32_t *const *in, size_t len) { static const uint32_t k[64] = { 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, @@ -126,6 +139,7 @@ static void sha256_list(uint32_t out[FASTD_SHA256_HASH_WORDS], const uint32_t *c out[i] = htonl(h[i]); } +/** Hashes a NULL-terminated va_list of complete input blocks */ static void sha256_blocks_va(uint32_t out[FASTD_SHA256_HASH_WORDS], va_list ap) { size_t count = 0; va_list ap2; @@ -145,6 +159,7 @@ static void sha256_blocks_va(uint32_t out[FASTD_SHA256_HASH_WORDS], va_list ap) sha256_list(out, blocks, count*FASTD_SHA256_BLOCK_BYTES); } +/** Hashes complete input blocks (argument list must by NULL-terminated) */ void fastd_sha256_blocks(fastd_sha256_t *out, ...) { va_list ap; @@ -153,6 +168,7 @@ void fastd_sha256_blocks(fastd_sha256_t *out, ...) { va_end(ap); } +/** Hashes a buffer of arbitraty length (must by 32bit-aligned) */ void fastd_sha256(fastd_sha256_t *out, const uint32_t *in, size_t len) { size_t i, count = (len+FASTD_SHA256_BLOCK_BYTES-1) / FASTD_SHA256_BLOCK_BYTES; const uint32_t *blocks[count]; @@ -163,6 +179,7 @@ void fastd_sha256(fastd_sha256_t *out, const uint32_t *in, size_t len) { sha256_list(out->w, blocks, len); } +/** Computes the HMAC-SHA256 of a list of (potentially incomplete) input blocks */ static void hmacsha256_list(fastd_sha256_t *out, const uint32_t key[FASTD_HMACSHA256_KEY_WORDS], const uint32_t *const *in, size_t len) { static const uint32_t ipad2[8] = { 0x36363636, @@ -205,6 +222,7 @@ static void hmacsha256_list(fastd_sha256_t *out, const uint32_t key[FASTD_HMACSH fastd_sha256_blocks(out, opad, opad2, temp, NULL); } +/** Computes the HMAC-SHA256 of a list of NULL-terminated va_list of input blocks */ static void hmacsha256_blocks_va(fastd_sha256_t *out, const uint32_t key[FASTD_HMACSHA256_KEY_WORDS], va_list ap) { size_t count = 0; va_list ap2; @@ -224,6 +242,8 @@ static void hmacsha256_blocks_va(fastd_sha256_t *out, const uint32_t key[FASTD_H hmacsha256_list(out, key, blocks, count*FASTD_SHA256_BLOCK_BYTES); } + +/** Computes the HMAC-SHA256 of the complete blocks given as arguments (the argument list must be NULL-terminated) */ void fastd_hmacsha256_blocks(fastd_sha256_t *out, const uint32_t key[FASTD_HMACSHA256_KEY_WORDS], ...) { va_list ap; @@ -232,6 +252,7 @@ void fastd_hmacsha256_blocks(fastd_sha256_t *out, const uint32_t key[FASTD_HMACS va_end(ap); } +/** Verifies the HMAC-SHA256 of the complete blocks given as arguments (the argument list must be NULL-terminated) */ bool fastd_hmacsha256_blocks_verify(const uint8_t mac[FASTD_SHA256_HASH_BYTES], const uint32_t key[FASTD_HMACSHA256_KEY_WORDS], ...) { va_list ap; fastd_sha256_t out; @@ -243,6 +264,7 @@ bool fastd_hmacsha256_blocks_verify(const uint8_t mac[FASTD_SHA256_HASH_BYTES], return !memcmp(out.b, mac, FASTD_SHA256_HASH_BYTES); } +/** Computes the HMAC-SHA256 of an arbitraty input buffer */ void fastd_hmacsha256(fastd_sha256_t *out, const uint32_t key[FASTD_HMACSHA256_KEY_WORDS], const uint32_t *in, size_t len) { size_t i, count = (len+FASTD_SHA256_BLOCK_BYTES-1) / FASTD_SHA256_BLOCK_BYTES; const uint32_t *blocks[count]; @@ -253,6 +275,7 @@ void fastd_hmacsha256(fastd_sha256_t *out, const uint32_t key[FASTD_HMACSHA256_K hmacsha256_list(out, key, blocks, len); } +/** Verifies the HMAC-SHA256 of an arbitraty input buffer */ bool fastd_hmacsha256_verify(const uint8_t mac[FASTD_SHA256_HASH_BYTES], const uint32_t key[FASTD_HMACSHA256_KEY_WORDS], const uint32_t *in, size_t len) { fastd_sha256_t out; |