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	ecc-curve.c
	NIST curves for various key sizes.

file	ecc-curve.h
	NIST curves for various key sizes.

file	ecc.h
	Header file of ECC.

file	sha-256.c
	Software implementation of SHA-256.

file	sha-256.h
	Platform-independent SHA-256 API.

file	ecc.c
	Adapter for uECC.

file	module-macros.h
	Applies settings that are mandatory for uECC.

Data Structures
struct	aes_128_driver
	Structure of AES drivers. More...

struct	ccm_star_driver
	Structure of CCM* drivers. More...

struct	ecc_curve_t
	Parameters of an ECC curve in little-endian word order. More...

struct	sha_256_driver
	Structure of SHA-256 drivers. More...

Functions
void	ecc_init (void)
	Initializes ECC.

process_mutex_t *	ecc_get_mutex (void)
	Provides a mutex to be locked before proceeding with ecc_enable().

int	ecc_enable (const ecc_curve_t *curve)
	Sets up the ECC driver.

struct pt *	ecc_get_protothread (void)
	Provides the protothread that runs long-running ECC operations.

char	ecc_validate_public_key (const uint8_t public_key, int result)
	Validates a public key.

void	ecc_compress_public_key (const uint8_t uncompressed_public_key, uint8_t compressed_public_key)
	Compresses a public key as per SECG SEC 1.

char	ecc_decompress_public_key (const uint8_t compressed_public_key, uint8_t uncompressed_public_key, int *result)
	Decompresses a public key.

char	ecc_sign (const uint8_t message_hash, const uint8_t private_key, uint8_t signature, int result)
	Generates an ECDSA signature for a message.

char	ecc_verify (const uint8_t signature, const uint8_t message_hash, const uint8_t public_key, int result)
	Verifies an ECDSA signature of a message.

char	ecc_generate_key_pair (uint8_t public_key, uint8_t private_key, int *result)
	Generates a public/private key pair.

char	ecc_generate_shared_secret (const uint8_t public_key, const uint8_t private_key, uint8_t shared_secret, int result)
	Generates a shared secret as per ECDH.

void	ecc_disable (void)
	Shuts down the ECC driver and unlocks the mutex.

void	sha_256_hmac_init (const uint8_t *key, size_t key_len)
	Initiates a stepwise HMAC-SHA-256 computation.

void	sha_256_hmac_update (const uint8_t *data, size_t data_len)
	Proceeds with the computation of an HMAC-SHA-256.

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_finish (uint8_t hmac[static 32])
	Finishes the computation of an HMAC-SHA-256.

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

◆ ecc_compress_public_key()

void ecc_compress_public_key	(	const uint8_t *	uncompressed_public_key,
		uint8_t *	compressed_public_key )

Compresses a public key as per SECG SEC 1.

Parameters

uncompressed_public_key	The uncompressed 2\|CURVE\|-byte public key.
compressed_public_key	The compressed (1+\|CURVE\|)-byte public key.

Definition at line 103 of file ecc.c.

◆ ecc_decompress_public_key()

char ecc_decompress_public_key	(	const uint8_t *	compressed_public_key,
		uint8_t *	uncompressed_public_key,
		int *	result )

Decompresses a public key.

Parameters

compressed_public_key	The compressed (1+\|CURVE\|)-byte public key.
uncompressed_public_key	The uncompressed 2\|CURVE\|-byte public key.
result	0 on success and else a driver-specific error code.

Definition at line 111 of file ecc.c.

References PT_BEGIN, and PT_END.

◆ ecc_enable()

int ecc_enable ( const ecc_curve_t * curve )

Sets up the ECC driver.

Parameters

curve The curve to use in subsequent calls.

Returns: 0 on success and else a driver-specific error code. On error, the mutex is unlocked automatically and there is no need to call ecc_disable() either.

Definition at line 72 of file ecc.c.

References process_mutex_unlock().

◆ ecc_generate_key_pair()

char ecc_generate_key_pair	(	uint8_t *	public_key,
		uint8_t *	private_key,
		int *	result )

Generates a public/private key pair.

Parameters

public_key	The 2\|CURVE\|-byte public key.
private_key	The \|CURVE\|-byte private key.
result	0 on success and else a driver-specific error code.

Definition at line 157 of file ecc.c.

References PT_BEGIN, and PT_END.

◆ ecc_generate_shared_secret()

char ecc_generate_shared_secret	(	const uint8_t *	public_key,
		const uint8_t *	private_key,
		uint8_t *	shared_secret,
		int *	result )

Generates a shared secret as per ECDH.

NOTE: Callers should derive symmetric keys from the shared secret via a key derivation function.

Parameters

public_key	The peer's 2\|CURVE\|-byte public key.
private_key	Our \|CURVE\|-byte private key.
shared_secret	The resultant \|CURVE\|-byte shared secret.
result	0 on success and else a driver-specific error code.

Definition at line 171 of file ecc.c.

References PT_BEGIN, and PT_END.

◆ ecc_get_mutex()

process_mutex_t * ecc_get_mutex ( void )

Provides a mutex to be locked before proceeding with ecc_enable().

Returns: The mutex.

Definition at line 66 of file ecc.c.

◆ ecc_get_protothread()

struct pt * ecc_get_protothread ( void )

Provides the protothread that runs long-running ECC operations.

Returns: The protothread that runs long-running ECC operations.

Definition at line 87 of file ecc.c.

◆ ecc_sign()

char ecc_sign	(	const uint8_t *	message_hash,
		const uint8_t *	private_key,
		uint8_t *	signature,
		int *	result )

Generates an ECDSA signature for a message.

Parameters

message_hash	The \|CURVE\|-byte hash over the message.
private_key	The \|CURVE\|-byte private key.
signature	The 2\|CURVE\|-byte signature.
result	0 on success and else a driver-specific error code.

Definition at line 126 of file ecc.c.

References ecc_curve_t::bytes, PT_BEGIN, and PT_END.

◆ ecc_validate_public_key()

char ecc_validate_public_key	(	const uint8_t *	public_key,
		int *	result )

Validates a public key.

Parameters

public_key	The 2\|CURVE\|-byte public key.
result	0 on success and else a driver-specific error code.

Definition at line 93 of file ecc.c.

References PT_BEGIN, and PT_END.

◆ ecc_verify()

char ecc_verify	(	const uint8_t *	signature,
		const uint8_t *	message_hash,
		const uint8_t *	public_key,
		int *	result )

Verifies an ECDSA signature of a message.

Parameters

signature	The 2\|CURVE\|-byte signature.
message_hash	The \|CURVE\|-byte hash over the message.
public_key	The 2\|CURVE\|-byte public key.
result	0 on success and else a driver-specific error code.

Definition at line 142 of file ecc.c.

References ecc_curve_t::bytes, PT_BEGIN, and PT_END.

◆ 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 443 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 415 of file sha-256.c.

References sha_256_hmac_init(), and sha_256_hmac_update().

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

◆ sha_256_hmac_finish()

void sha_256_hmac_finish ( uint8_t hmac[static 32] )

Finishes the computation of an HMAC-SHA-256.

Parameters

hmac	pointer to where the resulting HMAC shall be stored

◆ sha_256_hmac_init()

void sha_256_hmac_init	(	const uint8_t *	key,
		size_t	key_len )

Initiates a stepwise HMAC-SHA-256 computation.

Parameters

key	the key to authenticate with
key_len	length of key in bytes

Definition at line 355 of file sha-256.c.

Referenced by sha_256_hkdf_expand().

◆ sha_256_hmac_update()

void sha_256_hmac_update	(	const uint8_t *	data,
		size_t	data_len )

Proceeds with the computation of an HMAC-SHA-256.

Parameters

data	further data to authenticate
data_len	length of data in bytes

Definition at line 380 of file sha-256.c.

Referenced by sha_256_hkdf_expand().

Topics

Files

Data Structures

Functions

Detailed Description

Function Documentation

◆ ecc_compress_public_key()

◆ ecc_decompress_public_key()

◆ ecc_enable()

◆ ecc_generate_key_pair()

◆ ecc_generate_shared_secret()

◆ ecc_get_mutex()

◆ ecc_get_protothread()

◆ ecc_sign()

◆ ecc_validate_public_key()

◆ ecc_verify()

◆ sha_256_hkdf()

◆ sha_256_hkdf_expand()

◆ sha_256_hkdf_extract()

◆ sha_256_hmac()

◆ sha_256_hmac_finish()

◆ sha_256_hmac_init()

◆ sha_256_hmac_update()