FIDO2 CTAP crypto

FIDO2 CTAP crypto helper. More...

Detailed Description

FIDO2 CTAP crypto helper.

Files
file	ctap_crypto.h
	FIDO2 CTAP crypto helper defines, structures and function declarations.

Data Structures
struct	ctap_crypto_pub_key_t
	Elliptic curve public key. More...
struct	ctap_crypto_key_agreement_key_t
	Key agreement key. More...

Macros
#define	CTAP_CRYPTO_KEY_SIZE   32
	Size in bytes of cryptographic keys used.
#define	CTAP_CRYPTO_ES256_DER_MAX_SIZE   72
	Max size of ES256 signature in ASN.1 DER format.

Functions
int	fido2_ctap_crypto_init (void)
	Initialize crypto helper.
int	fido2_ctap_crypto_prng (uint8_t *buf, size_t len)
	Wrapper function for random_bytes.
int	fido2_ctap_crypto_sha256_init (sha256_context_t *ctx)
	Wrapper function for sha256_init.
int	fido2_ctap_crypto_sha256_update (sha256_context_t *ctx, const void *data, size_t len)
	Wrapper function for sha256_update.
int	fido2_ctap_crypto_sha256_final (sha256_context_t *ctx, void *digest)
	Wrapper for sha256_final.
int	fido2_ctap_crypto_sha256 (const void *data, size_t len, void *digest)
	Wrapper function for sha256.
int	fido2_ctap_crypto_hmac_sha256_init (hmac_context_t *ctx, const void *key, size_t key_length)
	Wrapper function for hmac_sha256_init.
int	fido2_ctap_crypto_hmac_sha256_update (hmac_context_t *ctx, const void *data, size_t len)
	Wrapper function for hmac_sha256_update.
int	fido2_ctap_crypto_hmac_sha256_final (hmac_context_t *ctx, void *digest)
	Wrapper function for hmac_sha256_final.
int	fido2_ctap_crypto_hmac_sha256 (const void *key, size_t key_length, const void *data, size_t len, void *digest)
	Wrapper function for hmac_sha256.
int	fido2_ctap_crypto_gen_keypair (ctap_crypto_pub_key_t *pub_key, uint8_t *priv_key, size_t len)
	Generate cryptographic key pair.
int	fido2_ctap_crypto_ecdh (uint8_t *out, size_t len, ctap_crypto_pub_key_t *pub_key, uint8_t *priv_key, size_t key_len)
	Elliptic-curve Diffie-Hellmann.
int	fido2_ctap_crypto_get_sig (uint8_t *hash, size_t hash_len, uint8_t *sig, size_t *sig_len, const uint8_t *key, size_t key_len)
	Create cryptographic signature.
int	fido2_ctap_crypto_aes_enc (uint8_t *out, size_t *out_len, uint8_t *in, size_t in_len, const uint8_t *key, size_t key_len)
	Encrypt data using AES-256-CBC.
int	fido2_ctap_crypto_aes_dec (uint8_t *out, size_t *out_len, uint8_t *in, size_t in_len, const uint8_t *key, size_t key_len)
	Decrypt data using AES-256-CBC.
int	fido2_ctap_crypto_aes_ccm_enc (uint8_t *out, size_t out_len, const uint8_t *in, size_t in_len, uint8_t *auth_data, size_t auth_data_len, uint8_t mac_len, uint8_t length_encoding, const uint8_t *nonce, size_t nonce_len, const uint8_t *key, size_t key_len)
	Encrypt data using AES-128-CCM.
int	fido2_ctap_crypto_aes_ccm_dec (uint8_t *out, size_t out_len, const uint8_t *in, size_t in_len, uint8_t *auth_data, size_t auth_data_len, uint8_t mac_len, uint8_t length_encoding, const uint8_t *nonce, size_t nonce_len, const uint8_t *key, size_t key_len)
	Encrypt data using AES-128-CCM.

Macro Definition Documentation

CTAP_CRYPTO_ES256_DER_MAX_SIZE

#define CTAP_CRYPTO_ES256_DER_MAX_SIZE   72

Max size of ES256 signature in ASN.1 DER format.

Definition at line 42 of file ctap_crypto.h.

CTAP_CRYPTO_KEY_SIZE

#define CTAP_CRYPTO_KEY_SIZE   32

Size in bytes of cryptographic keys used.

Definition at line 37 of file ctap_crypto.h.

Function Documentation

fido2_ctap_crypto_aes_ccm_dec()

int fido2_ctap_crypto_aes_ccm_dec	(	uint8_t *	out,
		size_t	out_len,
		const uint8_t *	in,
		size_t	in_len,
		uint8_t *	auth_data,
		size_t	auth_data_len,
		uint8_t	mac_len,
		uint8_t	length_encoding,
		const uint8_t *	nonce,
		size_t	nonce_len,
		const uint8_t *	key,
		size_t	key_len
	)

Encrypt data using AES-128-CCM.

Parameters

[in]	out	encrypted data
[in]	out_len	length of out
[in]	in	data to be encrypted
[in]	in_len	length of in
[in]	auth_data	additional data to authenticate in MAC
[in]	auth_data_len	length of auth_data
[in]	mac_len	length of appended MAC
[in]	length_encoding	max supported length of plaintext
[in]	nonce	nonce for ctr mode encryption
[in]	nonce_len	length of nonce
[in]	key	symmetric key to use for encryption
[in]	key_len	length of key

Returns

ctap_status_codes_t

fido2_ctap_crypto_aes_ccm_enc()

int fido2_ctap_crypto_aes_ccm_enc	(	uint8_t *	out,
		size_t	out_len,
		const uint8_t *	in,
		size_t	in_len,
		uint8_t *	auth_data,
		size_t	auth_data_len,
		uint8_t	mac_len,
		uint8_t	length_encoding,
		const uint8_t *	nonce,
		size_t	nonce_len,
		const uint8_t *	key,
		size_t	key_len
	)

Encrypt data using AES-128-CCM.

Parameters

[in]	out	encrypted data
[in]	out_len	length of out
[in]	in	data to be encrypted
[in]	in_len	length of in
[in]	auth_data	additional data to authenticate in MAC
[in]	auth_data_len	length of auth_data
[in]	mac_len	length of appended MAC
[in]	length_encoding	max supported length of plaintext
[in]	nonce	nonce for ctr mode encryption
[in]	nonce_len	length of nonce
[in]	key	symmetric key to use for encryption
[in]	key_len	length of key

Returns

ctap_status_codes_t

fido2_ctap_crypto_aes_dec()

int fido2_ctap_crypto_aes_dec	(	uint8_t *	out,
		size_t *	out_len,
		uint8_t *	in,
		size_t	in_len,
		const uint8_t *	key,
		size_t	key_len
	)

Decrypt data using AES-256-CBC.

Parameters

[in]	out	decrypted data
[in]	out_len	length of out
[in]	in	encrypted data
[in]	in_len	len of in
[in]	key	symmetric key to use for decryption
[in]	key_len	length of key

Returns

ctap_status_codes_t

fido2_ctap_crypto_aes_enc()

int fido2_ctap_crypto_aes_enc	(	uint8_t *	out,
		size_t *	out_len,
		uint8_t *	in,
		size_t	in_len,
		const uint8_t *	key,
		size_t	key_len
	)

Encrypt data using AES-256-CBC.

Parameters

[in]	out	encrypted data
[in]	out_len	length of out
[in]	in	data to be encrypted
[in]	in_len	length of in
[in]	key	symmetric key to use for encryption
[in]	key_len	length of key

Returns

ctap_status_codes_t

fido2_ctap_crypto_ecdh()

int fido2_ctap_crypto_ecdh	(	uint8_t *	out,
		size_t	len,
		ctap_crypto_pub_key_t *	pub_key,
		uint8_t *	priv_key,
		size_t	key_len
	)

Elliptic-curve Diffie-Hellmann.

Parameters

[in]	out	shared secret buffer
[in]	len	length of out
[in]	pub_key	public key of other party
[in]	priv_key	private key
[in]	key_len	length of priv_key

Returns

ctap_status_codes_t

fido2_ctap_crypto_gen_keypair()

int fido2_ctap_crypto_gen_keypair	(	ctap_crypto_pub_key_t *	pub_key,
		uint8_t *	priv_key,
		size_t	len
	)

Generate cryptographic key pair.

Parameters

[in]	pub_key	public key buffer
[in]	priv_key	private key buffer
[in]	len	length of priv_key

Returns

ctap_status_codes_t

fido2_ctap_crypto_get_sig()

int fido2_ctap_crypto_get_sig	(	uint8_t *	hash,
		size_t	hash_len,
		uint8_t *	sig,
		size_t *	sig_len,
		const uint8_t *	key,
		size_t	key_len
	)

Create cryptographic signature.

Parameters

[in]	hash	Hash to be signed
[in]	hash_len	length of hash
[in]	sig	signature buffer
[in]	sig_len	length of sig
[in]	key	private key to use for signature
[in]	key_len	length of key

Returns

ctap_status_codes_t

fido2_ctap_crypto_hmac_sha256()

int fido2_ctap_crypto_hmac_sha256	(	const void *	key,
		size_t	key_length,
		const void *	data,
		size_t	len,
		void *	digest
	)

Wrapper function for hmac_sha256.

Parameters

[in]	key	key used in the hmac-sha256 computation
[in]	key_length	length of key
[in]	data	pointer to the buffer to generate the hmac-sha256
[in]	len	length of data
[out]	digest	the computed hmac-sha256, length MUST be SHA256_DIGEST_LENGTH

Note

discards the pointer returned by hmac_sha256

Returns

ctap_status_codes_t

fido2_ctap_crypto_hmac_sha256_final()

int fido2_ctap_crypto_hmac_sha256_final	(	hmac_context_t *	ctx,
		void *	digest
	)

Wrapper function for hmac_sha256_final.

Parameters

[in]	ctx	hmac_context_t handle to use
[out]	digest	the computed hmac-sha256, length MUST be SHA256_DIGEST_LENGTH

Returns

ctap_status_codes_t

fido2_ctap_crypto_hmac_sha256_init()

int fido2_ctap_crypto_hmac_sha256_init	(	hmac_context_t *	ctx,
		const void *	key,
		size_t	key_length
	)

Wrapper function for hmac_sha256_init.

Parameters

[in]	ctx	hmac_context_t handle to use
[in]	key	key used in the hmac-sha256 computation
[in]	key_length	length of key

Returns

ctap_status_codes_t

fido2_ctap_crypto_hmac_sha256_update()

int fido2_ctap_crypto_hmac_sha256_update	(	hmac_context_t *	ctx,
		const void *	data,
		size_t	len
	)

Wrapper function for hmac_sha256_update.

Parameters

[in]	ctx	hmac_context_t handle to use
[in]	data	pointer to the buffer to generate hash from
[in]	len	length of data

Returns

ctap_status_codes_t

fido2_ctap_crypto_init()

int fido2_ctap_crypto_init

(

void

)

Initialize crypto helper.

Initializes crypto libs and creates key_agreement key pair

Returns

ctap_status_codes_t

fido2_ctap_crypto_prng()

int fido2_ctap_crypto_prng	(	uint8_t *	buf,
		size_t	len
	)

Wrapper function for random_bytes.

Parameters

[in]	buf	buffer to hold random bytes
[in]	len	length of buf

Returns

ctap_status_codes_t

fido2_ctap_crypto_sha256()

int fido2_ctap_crypto_sha256	(	const void *	data,
		size_t	len,
		void *	digest
	)

Wrapper function for sha256.

Parameters

[in]	data	pointer to the buffer to generate hash from
[in]	len	length of data
[out]	digest	optional pointer to an array for the result, length must be SHA256_DIGEST_LENGTH

Note

discards the pointer returned by sha256

Returns

ctap_status_codes_t

fido2_ctap_crypto_sha256_final()

int fido2_ctap_crypto_sha256_final	(	sha256_context_t *	ctx,
		void *	digest
	)

Wrapper for sha256_final.

Parameters

ctx	sha256_context_t handle to use
digest	resulting digest, this is the hash of all the bytes

Returns

ctap_status_codes_t

fido2_ctap_crypto_sha256_init()

int fido2_ctap_crypto_sha256_init

(

sha256_context_t *

ctx

)

Wrapper function for sha256_init.

Parameters

ctx	sha256_context_t handle to init

Returns

ctap_status_codes_t

fido2_ctap_crypto_sha256_update()

int fido2_ctap_crypto_sha256_update	(	sha256_context_t *	ctx,
		const void *	data,
		size_t	len
	)

Wrapper function for sha256_update.

Parameters

	ctx	sha256_context_t handle to use
[in]	data	Input data
[in]	len	Length of data

Returns

ctap_status_codes_t