wolfCrypt Init and Cleanup

Functions

	Name
int	wc_HashGetOID(enum wc_HashType hash_type) This function will return the OID for the wc_HashType provided.
int	wc_HashGetDigestSize(enum wc_HashType hash_type) This function returns the size of the digest (output) for a hash_type. The returns size is used to make sure the output buffer provided to wc_Hash is large enough.
int	wc_Hash(enum wc_HashType hash_type, const byte * data, word32 data_len, byte * hash, word32 hash_len) This function performs a hash on the provided data buffer and returns it in the hash buffer provided.
int	wc_UnpackOctets(byte * out, word32 outSz, const byte * in, word32 inSz, word32 octetSz) Expands a packed octet stream into the one_octet_per_byte_cell form every wolfCrypt byte* API expects. Declared only when WOLFSSL_WIDE_BYTE is set (CHAR_BIT != 8); elsewhere the two layouts coincide and no conversion is needed.
int	wc_PackOctets(byte * out, word32 outSz, const byte * in, word32 inSz, word32 octetSz) Packs a one_octet_per_byte_cell buffer into an octet stream, for storing to flash or handing to a byte_oriented peripheral. Inverse of wc_UnpackOctets(); requires WOLFSSL_WIDE_BYTE.
int	wolfCrypt_Init(void ) Used to initialize resources used by wolfCrypt.
int	wolfCrypt_Cleanup(void ) Used to clean up resources used by wolfCrypt.

Functions Documentation

function wc_HashGetOID

int wc_HashGetOID(
    enum wc_HashType hash_type
)

This function will return the OID for the wc_HashType provided.

Parameters:

hash_type A hash type from the “enum wc_HashType” such as “WC_HASH_TYPE_SHA256”.

See:

Return:

OID returns value greater than 0
HASH_TYPE_E hash type not supported.
BAD_FUNC_ARG one of the provided arguments is incorrect.

Example

enum wc_HashType hash_type = WC_HASH_TYPE_SHA256;
int oid = wc_HashGetOID(hash_type);
if (oid > 0) {
    // Success
}

function wc_HashGetDigestSize

int wc_HashGetDigestSize(
    enum wc_HashType hash_type
)

This function returns the size of the digest (output) for a hash_type. The returns size is used to make sure the output buffer provided to wc_Hash is large enough.

Parameters:

hash_type A hash type from the “enum wc_HashType” such as “WC_HASH_TYPE_SHA256”.

See: wc_Hash

Return:

Success A positive return value indicates the digest size for the hash.
Error Returns HASH_TYPE_E if hash_type is not supported.
Failure Returns BAD_FUNC_ARG if an invalid hash_type was used.

Example

int hash_len = wc_HashGetDigestSize(hash_type);
if (hash_len <= 0) {
WOLFSSL_MSG("Invalid hash type/len");
return BAD_FUNC_ARG;
}

function wc_Hash

int wc_Hash(
    enum wc_HashType hash_type,
    const byte * data,
    word32 data_len,
    byte * hash,
    word32 hash_len
)

This function performs a hash on the provided data buffer and returns it in the hash buffer provided.

Parameters:

hash_type A hash type from the “enum wc_HashType” such as “WC_HASH_TYPE_SHA256”.
data Pointer to buffer containing the data to hash.
data_len Length of the data buffer.
hash Pointer to buffer used to output the final hash to.
hash_len Length of the hash buffer.

See: wc_HashGetDigestSize

Return: 0 Success, else error (such as BAD_FUNC_ARG or BUFFER_E).

Example

enum wc_HashType hash_type = WC_HASH_TYPE_SHA256;
int hash_len = wc_HashGetDigestSize(hash_type);
if (hash_len > 0) {
    int ret = wc_Hash(hash_type, data, data_len, hash_data, hash_len);
    if(ret == 0) {
        // Success
    }
}

function wc_UnpackOctets

int wc_UnpackOctets(
    byte * out,
    word32 outSz,
    const byte * in,
    word32 inSz,
    word32 octetSz
)

Expands a packed octet stream into the one-octet-per-byte-cell form every wolfCrypt byte* API expects. Declared only when WOLFSSL_WIDE_BYTE is set (CHAR_BIT != 8); elsewhere the two layouts coincide and no conversion is needed.

Parameters:

out Destination, one octet per cell
outSz Size of out in byte cells
in Packed source, WC_OCTETS_PER_BYTE octets per cell, low octet first, and must not overlap out
inSz Size of in in byte cells; must be at least WC_PACKED_CELLS(octetSz)
octetSz Number of octets to expand

See: wc_PackOctets

Return:

0 on success
BAD_FUNC_ARG when out or in is NULL
BUFFER_E when out is smaller than octetSz, or in smaller than WC_PACKED_CELLS(octetSz)

Example

byte sig[WC_MLDSA_65_SIG_SIZE];
int ret = wc_UnpackOctets(sig, (word32)sizeof(sig), sigPacked,
                          (word32)sizeof(sigPacked),
                          WC_MLDSA_65_SIG_SIZE);

function wc_PackOctets

int wc_PackOctets(
    byte * out,
    word32 outSz,
    const byte * in,
    word32 inSz,
    word32 octetSz
)

Packs a one-octet-per-byte-cell buffer into an octet stream, for storing to flash or handing to a byte-oriented peripheral. Inverse of wc_UnpackOctets(); requires WOLFSSL_WIDE_BYTE.

Parameters:

out Destination for the packed stream
outSz Size of out in byte cells
in Source, one octet per cell, and must not overlap out
inSz Size of in in byte cells; must be at least octetSz
octetSz Number of octets to pack

See: wc_UnpackOctets

Return:

0 on success
BAD_FUNC_ARG when out or in is NULL
BUFFER_E when out is smaller than WC_PACKED_CELLS(octetSz), or in smaller than octetSz

Example

byte packed[WC_PACKED_CELLS(sizeof(sig))];
int ret = wc_PackOctets(packed, (word32)sizeof(packed), sig,
                        (word32)sizeof(sig), (word32)sizeof(sig));

function wolfCrypt_Init

int wolfCrypt_Init(
    void 
)

Used to initialize resources used by wolfCrypt.

Parameters:

none No parameters.

See: wolfCrypt_Cleanup

Return:

0 upon success.
<0 upon failure of init resources.

Example

...
if (wolfCrypt_Init() != 0) {
    WOLFSSL_MSG("Error with wolfCrypt_Init call");
}

function wolfCrypt_Cleanup

int wolfCrypt_Cleanup(
    void 
)

Used to clean up resources used by wolfCrypt.

Parameters:

none No parameters.

See: wolfCrypt_Init

Return:

0 upon success.
<0 upon failure of cleaning up resources.

Example

...
if (wolfCrypt_Cleanup() != 0) {
    WOLFSSL_MSG("Error with wolfCrypt_Cleanup call");
}

Updated on 2026-09-17 at 01:17:40 +0000