sha256.h File Reference

SHA256 hash implementation and interface functions. More...

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Macros
#define	SHA256_MAC_LEN   32

Functions
int	hmac_sha256_vector (const u8 *key, size_t key_len, size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
	HMAC-SHA256 over data vector (RFC 2104) More...
int	hmac_sha256 (const u8 *key, size_t key_len, const u8 *data, size_t data_len, u8 *mac)
	HMAC-SHA256 over data buffer (RFC 2104) More...
void	sha256_prf (const u8 *key, size_t key_len, const char *label, const u8 *data, size_t data_len, u8 *buf, size_t buf_len)
	SHA256-based Pseudo-Random Function (IEEE 802.11r, 8.5.1.5.2) More...
void	sha256_prf_bits (const u8 *key, size_t key_len, const char *label, const u8 *data, size_t data_len, u8 *buf, size_t buf_len_bits)
	IEEE Std 802.11-2012, 11.6.1.7.2 Key derivation function. More...
void	tls_prf_sha256 (const u8 *secret, size_t secret_len, const char *label, const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
	Pseudo-Random Function for TLS v1.2 (P_SHA256, RFC 5246) More...
int	hmac_sha256_kdf (const u8 *secret, size_t secret_len, const char *label, const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
	HMAC-SHA256 based KDF (RFC 5295) More...

Detailed Description

SHA256 hash implementation and interface functions.

Function Documentation

int hmac_sha256	(	const u8 *	key,
		size_t	key_len,
		const u8 *	data,
		size_t	data_len,
		u8 *	mac
	)

HMAC-SHA256 over data buffer (RFC 2104)

Parameters

key	Key for HMAC operations
key_len	Length of the key in bytes
data	Pointers to the data area
data_len	Length of the data area
mac	Buffer for the hash (32 bytes)

Returns

0 on success, -1 on failure

int hmac_sha256_kdf	(	const u8 *	secret,
		size_t	secret_len,
		const char *	label,
		const u8 *	seed,
		size_t	seed_len,
		u8 *	out,
		size_t	outlen
	)

HMAC-SHA256 based KDF (RFC 5295)

Parameters

secret	Key for KDF
secret_len	Length of the key in bytes
label	A unique label for each purpose of the KDF
seed	Seed value to bind into the key
seed_len	Length of the seed
out	Buffer for the generated pseudo-random key
outlen	Number of bytes of key to generate

Returns

0 on success, -1 on failure.

This function is used to derive new, cryptographically separate keys from a given key in ERP. This KDF is defined in RFC 5295, Chapter 3.1.2.

int hmac_sha256_vector	(	const u8 *	key,
		size_t	key_len,
		size_t	num_elem,
		const u8 *	addr[],
		const size_t *	len,
		u8 *	mac
	)

HMAC-SHA256 over data vector (RFC 2104)

Parameters

key	Key for HMAC operations
key_len	Length of the key in bytes
num_elem	Number of elements in the data vector
addr	Pointers to the data areas
len	Lengths of the data blocks
mac	Buffer for the hash (32 bytes)

Returns

0 on success, -1 on failure

void sha256_prf	(	const u8 *	key,
		size_t	key_len,
		const char *	label,
		const u8 *	data,
		size_t	data_len,
		u8 *	buf,
		size_t	buf_len
	)

SHA256-based Pseudo-Random Function (IEEE 802.11r, 8.5.1.5.2)

Parameters

key	Key for PRF
key_len	Length of the key in bytes
label	A unique label for each purpose of the PRF
data	Extra data to bind into the key
data_len	Length of the data
buf	Buffer for the generated pseudo-random key
buf_len	Number of bytes of key to generate

This function is used to derive new, cryptographically separate keys from a given key.

void sha256_prf_bits	(	const u8 *	key,
		size_t	key_len,
		const char *	label,
		const u8 *	data,
		size_t	data_len,
		u8 *	buf,
		size_t	buf_len_bits
	)

IEEE Std 802.11-2012, 11.6.1.7.2 Key derivation function.

Parameters

key	Key for KDF
key_len	Length of the key in bytes
label	A unique label for each purpose of the PRF
data	Extra data to bind into the key
data_len	Length of the data
buf	Buffer for the generated pseudo-random key
buf_len	Number of bits of key to generate

This function is used to derive new, cryptographically separate keys from a given key. If the requested buf_len is not divisible by eight, the least significant 1-7 bits of the last octet in the output are not part of the requested output.

void tls_prf_sha256	(	const u8 *	secret,
		size_t	secret_len,
		const char *	label,
		const u8 *	seed,
		size_t	seed_len,
		u8 *	out,
		size_t	outlen
	)

Pseudo-Random Function for TLS v1.2 (P_SHA256, RFC 5246)

Parameters

secret	Key for PRF
secret_len	Length of the key in bytes
label	A unique label for each purpose of the PRF
seed	Seed value to bind into the key
seed_len	Length of the seed
out	Buffer for the generated pseudo-random key
outlen	Number of bytes of key to generate

Returns

0 on success, -1 on failure.

This function is used to derive new, cryptographically separate keys from a given key in TLS. This PRF is defined in RFC 2246, Chapter 5.