SHA-3

The SHA3-256 and SHA3-512 functions are provided for interoperability with other applications and protocols. If you are looking for a general-purpose hash function and not specifically SHA-3, using crypto_generichash() (BLAKE2b) is usually a better choice.

These functions are also not suitable for hashing passwords or deriving keys from passwords. Use one of the password hashing APIs instead.

These functions are not keyed and are thus deterministic.

A message can be hashed in a single pass, but a streaming API is also available to process a message as a sequence of multiple chunks.

All these functions return 0 on success.

Single-part SHA3-256 example

#define MESSAGE ((const unsigned char *) "test")
#define MESSAGE_LEN 4

unsigned char out[crypto_hash_sha3256_BYTES];

crypto_hash_sha3256(out, MESSAGE, MESSAGE_LEN);

Single-part SHA3-512 example

#define MESSAGE ((const unsigned char *) "test")
#define MESSAGE_LEN 4

unsigned char out[crypto_hash_sha3512_BYTES];

crypto_hash_sha3512(out, MESSAGE, MESSAGE_LEN);

Multi-part SHA3-256 example

#define MESSAGE_PART1 \
    ((const unsigned char *) "Arbitrary data to hash")
#define MESSAGE_PART1_LEN 22

#define MESSAGE_PART2 \
    ((const unsigned char *) "is longer than expected")
#define MESSAGE_PART2_LEN 23

unsigned char out[crypto_hash_sha3256_BYTES];
crypto_hash_sha3256_state state;

crypto_hash_sha3256_init(&state);

crypto_hash_sha3256_update(&state, MESSAGE_PART1, MESSAGE_PART1_LEN);
crypto_hash_sha3256_update(&state, MESSAGE_PART2, MESSAGE_PART2_LEN);

crypto_hash_sha3256_final(&state, out);

Usage

SHA3-256

Single-part:

int crypto_hash_sha3256(unsigned char *out, const unsigned char *in,
                        unsigned long long inlen);

Multi-part:

int crypto_hash_sha3256_init(crypto_hash_sha3256_state *state);

int crypto_hash_sha3256_update(crypto_hash_sha3256_state *state,
                               const unsigned char *in,
                               unsigned long long inlen);

int crypto_hash_sha3256_final(crypto_hash_sha3256_state *state,
                              unsigned char *out);

SHA3-512

Single-part:

int crypto_hash_sha3512(unsigned char *out, const unsigned char *in,
                        unsigned long long inlen);

Multi-part:

int crypto_hash_sha3512_init(crypto_hash_sha3512_state *state);

int crypto_hash_sha3512_update(crypto_hash_sha3512_state *state,
                               const unsigned char *in,
                               unsigned long long inlen);

int crypto_hash_sha3512_final(crypto_hash_sha3512_state *state,
                              unsigned char *out);

Notes

The state must be initialized with crypto_hash_sha3*_init() before updating or finalizing it.

After crypto_hash_sha3*_final(), the state should not be used any more, unless it is reinitialized using crypto_hash_sha3*_init().

The crypto_hash_sha3256_statebytes() and crypto_hash_sha3512_statebytes() helper functions return the size of the corresponding state structures and are useful when state objects need to be allocated dynamically.

These functions were introduced in libsodium 1.0.22.

Constants

• crypto_hash_sha3256_BYTES

• crypto_hash_sha3512_BYTES

Data types

• crypto_hash_sha3256_state

• crypto_hash_sha3512_state