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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
keyKey for PRF
key_lenLength of the key in bytes
labelA unique label for each purpose of the PRF
dataExtra data to bind into the key
data_lenLength of the data
bufBuffer for the generated pseudo-random key
buf_lenNumber 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
keyKey for KDF
key_lenLength of the key in bytes
labelA unique label for each purpose of the PRF
dataExtra data to bind into the key
data_lenLength of the data
bufBuffer for the generated pseudo-random key
buf_lenNumber 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.