hmac_sha256.h (2411B)
1 #ifndef CCAN_CRYPTO_HMAC_SHA256_H 2 #define CCAN_CRYPTO_HMAC_SHA256_H 3 /* BSD-MIT - see LICENSE file for details */ 4 #include "config.h" 5 #include <stdint.h> 6 #include <stdlib.h> 7 #include "sha256.h" 8 9 /* Number of bytes per block. */ 10 #define HMAC_SHA256_BLOCKSIZE 64 11 12 /** 13 * struct hmac_sha256 - structure representing a completed HMAC. 14 */ 15 struct hmac_sha256 { 16 struct sha256 sha; 17 }; 18 19 /** 20 * hmac_sha256 - return hmac of an object with a key. 21 * @hmac: the hmac to fill in 22 * @k: pointer to the key, 23 * @ksize: the number of bytes pointed to by @k 24 * @d: pointer to memory, 25 * @dsize: the number of bytes pointed to by @d 26 */ 27 void hmac_sha256(struct hmac_sha256 *hmac, 28 const void *k, size_t ksize, 29 const void *d, size_t dsize); 30 31 /** 32 * struct hmac_sha256_ctx - structure to store running context for hmac_sha256 33 */ 34 struct hmac_sha256_ctx { 35 struct sha256_ctx sha; 36 uint64_t k_opad[HMAC_SHA256_BLOCKSIZE / sizeof(uint64_t)]; 37 }; 38 39 /** 40 * hmac_sha256_init - initialize an HMAC_SHA256 context. 41 * @ctx: the hmac_sha256_ctx to initialize 42 * @k: pointer to the key, 43 * @ksize: the number of bytes pointed to by @k 44 * 45 * This must be called before hmac_sha256_update or hmac_sha256_done. 46 * 47 * If it was already initialized, this forgets anything which was 48 * hashed before. 49 * 50 * Example: 51 * static void hmac_all(const char *key, 52 * const char **arr, struct hmac_sha256 *hash) 53 * { 54 * size_t i; 55 * struct hmac_sha256_ctx ctx; 56 * 57 * hmac_sha256_init(&ctx, key, strlen(key)); 58 * for (i = 0; arr[i]; i++) 59 * hmac_sha256_update(&ctx, arr[i], strlen(arr[i])); 60 * hmac_sha256_done(&ctx, hash); 61 * } 62 */ 63 void hmac_sha256_init(struct hmac_sha256_ctx *ctx, 64 const void *k, size_t ksize); 65 66 /** 67 * hmac_sha256_update - include some memory in the hash. 68 * @ctx: the hmac_sha256_ctx to use 69 * @p: pointer to memory, 70 * @size: the number of bytes pointed to by @p 71 * 72 * You can call this multiple times to hash more data, before calling 73 * hmac_sha256_done(). 74 */ 75 void hmac_sha256_update(struct hmac_sha256_ctx *ctx, const void *p, size_t size); 76 77 /** 78 * hmac_sha256_done - finish HMAC_SHA256 and return the hash 79 * @ctx: the hmac_sha256_ctx to complete 80 * @res: the hash to return. 81 * 82 * Note that @ctx is *destroyed* by this, and must be reinitialized. 83 * To avoid that, pass a copy instead. 84 */ 85 void hmac_sha256_done(struct hmac_sha256_ctx *hmac_sha256, struct hmac_sha256 *res); 86 #endif /* CCAN_CRYPTO_HMAC_SHA256_H */