File syn_hmac.h¶

FileList > src > syntropic > util > syn_hmac.h

HMAC-SHA256 — keyed-hash message authentication code. More...

#include "syn_sha256.h"
#include <stddef.h>
#include <stdint.h>
#include <string.h>

Classes¶

Type	Name
struct	SYN_HMAC_SHA256 HMAC-SHA256 context — caller-owned.

Public Static Functions¶

Type	Name
void	syn_hmac_sha256 (const void * key, size_t key_len, const void * data, size_t data_len, uint8_t mac) Compute HMAC-SHA256 in one shot.
void	syn_hmac_sha256_final (SYN_HMAC_SHA256 * ctx, uint8_t mac) Finalize and produce the 32-byte HMAC.
void	syn_hmac_sha256_init (SYN_HMAC_SHA256 * ctx, const void * key, size_t key_len) Initialize HMAC-SHA256 with a key.
void	syn_hmac_sha256_update (SYN_HMAC_SHA256 * ctx, const void * data, size_t len) Feed message data into the HMAC.

Macros¶

Type	Name
define	SYN_HMAC_SHA256_SIZE `[SYN\_SHA256\_DIGEST\_SIZE](syn__sha256_8h.md#define-syn_sha256_digest_size)` HMAC-SHA256 output size in bytes.

Detailed Description¶

Built on top of syn_sha256. Provides the same streaming pattern: init (with key) → update → final

The context wraps two SHA-256 contexts (~224 bytes caller-owned). No heap, no external dependencies.

** **

// One-shot:
uint8_t mac[32];
syn_hmac_sha256(key, key_len, message, msg_len, mac);

// Streaming:
SYN_HMAC_SHA256 ctx;
syn_hmac_sha256_init(&ctx, key, key_len);
syn_hmac_sha256_update(&ctx, chunk1, len1);
syn_hmac_sha256_update(&ctx, chunk2, len2);
syn_hmac_sha256_final(&ctx, mac);

Public Static Functions Documentation¶

function syn_hmac_sha256¶

Compute HMAC-SHA256 in one shot.

static inline void syn_hmac_sha256 (
    const void * key,
    size_t key_len,
    const void * data,
    size_t data_len,
    uint8_t mac
)

Parameters:

key Secret key.
key_len Key length in bytes.
data Message data.
data_len Message length in bytes.
mac Output buffer (must be at least 32 bytes).

function syn_hmac_sha256_final¶

Finalize and produce the 32-byte HMAC.

static inline void syn_hmac_sha256_final (
    SYN_HMAC_SHA256 * ctx,
    uint8_t mac
)

Parameters:

ctx HMAC context.
mac Output buffer (must be at least 32 bytes).

function syn_hmac_sha256_init¶

Initialize HMAC-SHA256 with a key.

static inline void syn_hmac_sha256_init (
    SYN_HMAC_SHA256 * ctx,
    const void * key,
    size_t key_len
)

If key_len > 64, the key is first hashed with SHA-256.

Parameters:

ctx HMAC context.
key Secret key.
key_len Key length in bytes.

function syn_hmac_sha256_update¶

Feed message data into the HMAC.

static inline void syn_hmac_sha256_update (
    SYN_HMAC_SHA256 * ctx,
    const void * data,
    size_t len
)

Parameters:

ctx HMAC context.
data Message data.
len Length in bytes.

Macro Definition Documentation¶

define SYN_HMAC_SHA256_SIZE¶

HMAC-SHA256 output size in bytes.

#define SYN_HMAC_SHA256_SIZE `SYN_SHA256_DIGEST_SIZE`

The documentation for this class was generated from the following file src/syntropic/util/syn_hmac.h