sha256-prf.c File Reference

SHA256-based PRF (IEEE 802.11r) More...

#include "includes.h"
#include "common.h"
#include "sha256.h"
#include "crypto.h"

Functions
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...

Detailed Description

SHA256-based PRF (IEEE 802.11r)

Function Documentation

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.