Cryptographic primitives

Topics
	Cryptographically-secure PRNG
	In contrast to a normal PRNG, a CSPRNG generates a stream of pseudo-random numbers that is indistinguishable from the uniform distribution to a computationally-bounded adversary who does not know the seed.

Files
file	aes-128.c
	Wrapped AES-128 implementation from Texas Instruments.
file	aes-128.h
	AES-128.
file	ccm-star.c
	AES_128-based CCM* implementation.
file	ccm-star.h
	CCM* header file.
file	sha-256.c
	Software implementation of SHA-256.
file	sha-256.h
	Platform-independent SHA-256 API.

Data Structures
struct	aes_128_driver
	Structure of AES drivers. More...
struct	ccm_star_driver
	Structure of CCM* drivers. More...
struct	sha_256_driver
	Structure of SHA-256 drivers. More...

Functions
void	sha_256_hkdf_expand (const uint8_t *prk, size_t prk_len, const uint8_t *info, size_t info_len, uint8_t *okm, uint_fast16_t okm_len)
	Expands a key as per RFC 5869.
void	sha_256_hkdf (const uint8_t *salt, size_t salt_len, const uint8_t *ikm, size_t ikm_len, const uint8_t *info, size_t info_len, uint8_t *okm, uint_fast16_t okm_len)
	Performs both extraction and expansion as per RFC 5869.
void	sha_256_hash (const uint8_t *data, size_t len, uint8_t digest[static 32])
	Generic implementation of sha_256_driver::hash.
void	sha_256_hmac (const uint8_t *key, size_t key_len, const uint8_t *data, size_t data_len, uint8_t hmac[static 32])
	Computes HMAC-SHA-256 as per RFC 2104.
void	sha_256_hkdf_extract (const uint8_t *salt, size_t salt_len, const uint8_t *ikm, size_t ikm_len, uint8_t prk[static 32])
	Extracts a key as per RFC 5869.

Detailed Description

Function Documentation

sha_256_hkdf()

void sha_256_hkdf	(	const uint8_t *	salt,
		size_t	salt_len,
		const uint8_t *	ikm,
		size_t	ikm_len,
		const uint8_t *	info,
		size_t	info_len,
		uint8_t *	okm,
		uint_fast16_t	okm_len )

Performs both extraction and expansion as per RFC 5869.

Parameters

salt	optional salt value
salt_len	length of salt in bytes
ikm	input keying material
ikm_len	length of ikm in bytes
info	optional context and application specific information
info_len	length of info in bytes
okm	output keying material
okm_len	length of okm in bytes (<= 255 * SHA_256_DIGEST_LENGTH)

Definition at line 449 of file sha-256.c.

References sha_256_hkdf_expand().

sha_256_hkdf_expand()

void sha_256_hkdf_expand	(	const uint8_t *	prk,
		size_t	prk_len,
		const uint8_t *	info,
		size_t	info_len,
		uint8_t *	okm,
		uint_fast16_t	okm_len )

Expands a key as per RFC 5869.

Parameters

prk	a pseudorandom key of at least SHA_256_DIGEST_LENGTH bytes
prk_len	length of prk in bytes
info	optional context and application specific information
info_len	length of info in bytes
okm	output keying material
okm_len	length of okm in bytes (<= 255 * SHA_256_DIGEST_LENGTH)

Definition at line 417 of file sha-256.c.

Referenced by sha_256_hkdf().

sha_256_hkdf_extract()

void sha_256_hkdf_extract	(	const uint8_t *	salt,
		size_t	salt_len,
		const uint8_t *	ikm,
		size_t	ikm_len,
		uint8_t	prk[static 32] )

Extracts a key as per RFC 5869.

Parameters

salt	optional salt value
salt_len	length of salt in bytes
ikm	input keying material
ikm_len	length of ikm in bytes
prk	pointer to where the extracted key shall be stored

sha_256_hmac()

void sha_256_hmac	(	const uint8_t *	key,
		size_t	key_len,
		const uint8_t *	data,
		size_t	data_len,
		uint8_t	hmac[static 32] )

Computes HMAC-SHA-256 as per RFC 2104.

Parameters

key	the key to authenticate with
key_len	length of key in bytes
data	the data to authenticate
data_len	length of data in bytes
hmac	pointer to where the resulting HMAC shall be stored