This is an implementation of Ephemeral Diffie-Hellman Over COSE (EDHOC), a very compact and lightweight authenticated Diffie-Hellman key exchange with ephemeral keys that provides mutual authentication, perfect forward secrecy, and identity protection as described in RFC9528. More...

Functions
void	edhoc_storage_init (void)
	Reserve memory for the EDHOC context struct.
uint8_t	edhoc_setup_suites (edhoc_context_t *ctx)
	Initialize the EDHOC Context with the defined EDHOC parameters.
void	edhoc_finalize (edhoc_context_t *ctx)
	Close the EDHOC context.
edhoc_error_t	edhoc_generate_message_1 (edhoc_context_t ctx, uint8_t ad, size_t ad_sz, bool suite_array)
	Generate the EDHOC Message 1 and set it in the EDHOC context.
edhoc_error_t	edhoc_generate_message_2 (edhoc_context_t ctx, const uint8_t auth_data, size_t auth_data_size)
	Generate the EDHOC Message 2 and set it in the EDHOC context.
edhoc_error_t	edhoc_generate_message_3 (edhoc_context_t ctx, const uint8_t auth_data, size_t auth_data_size)
	Generate the EDHOC Message 3 and set it in the EDHOC context.
uint8_t	edhoc_generate_error_message (uint8_t msg_er, size_t msg_er_sz, const edhoc_context_t ctx, int8_t err)
	Generate the EDHOC ERROR Message.
int	edhoc_authenticate_msg (edhoc_context_t ctx, uint8_t ad, bool msg2)
	Authenticate the rx message.
int16_t	edhoc_kdf (const uint8_t prk, uint8_t info_label, const uint8_t context, uint8_t context_sz, uint16_t length, uint8_t *result)
	EDHOC Key Derivation Function (KDF) based on HMAC-based Expand (RFC 5869).
int16_t	edhoc_expand (const uint8_t prk, const uint8_t info, uint16_t info_sz, uint16_t length, uint8_t *result)
	HMAC-based Key Expansion Function for EDHOC context using HKDF (RFC 5869).
uint8_t	edhoc_initialize_context (edhoc_context_t *ctx)
	Internal API functions.
uint8_t	edhoc_get_own_auth_key (edhoc_context_t ctx, cose_key_t *key)
	Retrieve own authentication key from key storage.
int8_t	edhoc_set_config_from_suite (edhoc_context_t *ctx, uint8_t suite)
	Set EDHOC configuration parameters based on cipher suite.
void	edhoc_print_session_info (const edhoc_context_t *ctx)
	Print current EDHOC session information for debugging.
int8_t	edhoc_generate_transcript_hash_2 (edhoc_context_t ctx, const uint8_t eph_pub, uint8_t *msg, uint16_t msg_sz)
	Generate transcript hash TH_2.
uint8_t	edhoc_generate_transcript_hash_3 (edhoc_context_t ctx, const uint8_t cred, uint16_t cred_sz, const uint8_t *plaintext, uint16_t plaintext_sz)
	Generate transcript hash TH_3.
uint8_t	edhoc_generate_transcript_hash_4 (edhoc_context_t ctx, const uint8_t cred, uint16_t cred_sz, const uint8_t *plaintext, uint16_t plaintext_sz)
	Generate transcript hash TH_4.
bool	edhoc_generate_prk_2e (edhoc_context_t *ctx)
	Generate pseudorandom key PRK_2e.
bool	edhoc_generate_prk_3e2m (edhoc_context_t ctx, const ecc_key_t auth_key, uint8_t gen)
	Generate pseudorandom key PRK_3e2m.
bool	edhoc_generate_prk_4e3m (edhoc_context_t ctx, const ecc_key_t auth_key, uint8_t gen)
	Generate pseudorandom key PRK_4e3m.
int16_t	edhoc_generate_keystream_2e (edhoc_context_t ctx, uint16_t length, uint8_t ks_2e)
	Generate keystream KS_2e for encryption.
int16_t	edhoc_enc_dec_ciphertext_2 (const edhoc_context_t ctx, const uint8_t ks_2e, uint8_t *plaintext, uint16_t plaintext_sz)
	Encrypt/decrypt ciphertext 2 using XOR with keystream.
size_t	edhoc_generate_cred_x (const cose_key_t cose, uint8_t cred, size_t cred_sz)
	Generate CBOR-encoded credential CRED_X.
size_t	edhoc_generate_id_cred_x (const cose_key_t cose, uint8_t cred, size_t cred_sz)
	Generate credential identifier ID_CRED_X.
uint8_t	edhoc_calc_mac (const edhoc_context_t ctx, uint8_t mac_num, uint8_t mac_len, uint8_t mac)
	Calculate message authentication code (MAC).
void	edhoc_print_config_summary (const edhoc_context_t *ctx)
	Print EDHOC session configuration summary.

Variables
edhoc_context_t *	edhoc_ctx
	EDHOC context struct used in the EDHOC protocol.

Detailed Description

This is an implementation of Ephemeral Diffie-Hellman Over COSE (EDHOC), a very compact and lightweight authenticated Diffie-Hellman key exchange with ephemeral keys that provides mutual authentication, perfect forward secrecy, and identity protection as described in RFC9528.

Function Documentation

◆ edhoc_authenticate_msg()

int edhoc_authenticate_msg	(	edhoc_context_t *	ctx,
		uint8_t *	ad,
		bool	msg2 )

Authenticate the rx message.

Parameters

ctx	EDHOC Context struct
ad	A pointer to a buffer to copy the Application Data of the rx message
msg2	Determines whether the message is a Message 2

Return values

negative	error code when an EDHOC ERROR is detected
ad_sz	The length of the Application Data received in Message 2, when EDHOC success

Used by Initiator and Responder EDHOC role to Authenticate the other party

Verify that the EDHOC Responder role identity is among the allowed if it is necessary
Verify MAC
Pass Application data AD

If any verification step fails to return an EDHOC ERROR code and, if all the steps success the length of the Application Data receive on the Message is returned.

Definition at line 867 of file edhoc.c.

References cbor_end_writer(), cbor_get_position(), cbor_get_remaining(), cbor_init_reader(), cbor_init_writer(), cbor_write_data(), cbor_write_object(), cose_sign1_verify(), edhoc_calc_mac(), EDHOC_ERR_CRYPTO_AUTHENTICATION, EDHOC_ERR_INTERNAL_ERROR, edhoc_generate_cred_x(), edhoc_generate_id_cred_x(), edhoc_generate_prk_3e2m(), edhoc_generate_prk_4e3m(), edhoc_generate_transcript_hash_4(), edhoc_get_ad(), edhoc_get_key_id_cred_x(), edhoc_get_sign(), EDHOC_MAX_AD_SZ, EDHOC_MAX_CRED_LEN, and edhoc_read_byte_identifier().

◆ edhoc_calc_mac()

uint8_t edhoc_calc_mac	(	const edhoc_context_t *	ctx,
		uint8_t	mac_num,
		uint8_t	mac_len,
		uint8_t *	mac )

Calculate message authentication code (MAC).

Parameters

ctx	EDHOC context
mac_num	MAC number (2 or 3)
mac_len	MAC length
mac	Output buffer for MAC

Returns: 1 on success, 0 on failure

Computes MAC_2 or MAC_3 for EDHOC message authentication

Definition at line 417 of file edhoc.c.

References cbor_end_writer(), cbor_init_writer(), cbor_write_data(), cbor_write_object(), edhoc_kdf(), EDHOC_MAX_CID_LEN, and EDHOC_ROLE.

Referenced by edhoc_authenticate_msg().

◆ edhoc_enc_dec_ciphertext_2()

int16_t edhoc_enc_dec_ciphertext_2	(	const edhoc_context_t *	ctx,
		const uint8_t *	ks_2e,
		uint8_t *	plaintext,
		uint16_t	plaintext_sz )

Encrypt/decrypt ciphertext 2 using XOR with keystream.

Parameters

ctx	EDHOC context
ks_2e	Keystream for XOR operation
plaintext	Input/output buffer for plaintext/ciphertext
plaintext_sz	Buffer size

Returns: Size of processed data

Performs XOR encryption/decryption of EDHOC message 2 content

Definition at line 665 of file edhoc.c.

Referenced by edhoc_generate_message_2(), and edhoc_handler_msg_2().

◆ edhoc_expand()

int16_t edhoc_expand	(	const uint8_t *	prk,
		const uint8_t *	info,
		uint16_t	info_sz,
		uint16_t	length,
		uint8_t *	result )

HMAC-based Key Expansion Function for EDHOC context using HKDF (RFC 5869).

Parameters

prk	PRK (Pseudorandom Key) - a pseudorandom key used as input for the HMAC-based key derivation.
info	Additional context information used in the key derivation, which is generated from the info_label and context.
info_sz	The size of the info parameter in bytes.
length	The desired length of the output key material (OKM) in bytes.
result	OKM (Output Keying Material) - the buffer where the derived key will be stored.

Returns: The number of output key bytes generated (equal to length).

This function implements the HKDF-Expand function as described in RFC 5869. It takes the PRK, context info, and the desired length to produce the final key material. It calls hkdf_expand internally to perform the HMAC-based key expansion using SHA-256.

The steps include:

Verifying the size of the info and output key material (OKM).
Using HMAC-Expand to expand the PRK and info into OKM.
Returning the length of the derived key or an error code in case of failure.

Example usage:

OKM = HKDF-Expand(PRK, info, length)

Definition at line 406 of file edhoc.c.

References sha_256_hkdf_expand().

Referenced by edhoc_kdf().

◆ edhoc_finalize()

void edhoc_finalize ( edhoc_context_t * ctx )

Close the EDHOC context.

Parameters

ctx	EDHOC context struct

Used by both Initiator and Responder EDHOC roles to de-allocate the memory reserved for the EDHOC context when EDHOC protocol finalize.

Definition at line 83 of file edhoc.c.

References memb_free().

Referenced by edhoc_client_close(), and edhoc_server_close().

◆ edhoc_generate_cred_x()

size_t edhoc_generate_cred_x	(	const cose_key_t *	cose,
		uint8_t *	cred,
		size_t	cred_sz )

Generate CBOR-encoded credential CRED_X.

Parameters

cose	COSE key containing credential information
cred	Output buffer for credential
cred_sz	Output buffer size

Returns: Size of generated credential, 0 on error

Generates CBOR credential structure from COSE key

Definition at line 210 of file edhoc.c.

References cbor_close_map(), cbor_end_writer(), cbor_init_writer(), cbor_open_map(), cbor_write_data(), cbor_write_signed(), cbor_write_text(), and cbor_write_unsigned().

Referenced by edhoc_authenticate_msg(), edhoc_generate_id_cred_x(), edhoc_generate_message_2(), and edhoc_generate_message_3().

◆ edhoc_generate_error_message()

uint8_t edhoc_generate_error_message	(	uint8_t *	msg_er,
		size_t	msg_er_sz,
		const edhoc_context_t *	ctx,
		int8_t	err )

Generate the EDHOC ERROR Message.

Parameters

msg_er	A pointer to a buffer to copy the generated CBOR message error
msg_er_sz	The size of the destination buffer
ctx	EDHOC Context struct
err	EDHOC error number

Returns: err_sz CBOR Message Error size

An EDHOC error message can be sent by both parties as a reply to any non-error EDHOC message. If any verification step fails on the EDHOC protocol the Initiator or Responder must send an EDHOC error message back that contains a brief human-readable diagnostic message.

msg_er = (?C_x_identifier, ERR_MSG:tstr)

Definition at line 784 of file edhoc.c.

References EDHOC_ERR_BUFFER_OVERFLOW, EDHOC_ERR_CID_INVALID, EDHOC_ERR_CORRELATION, EDHOC_ERR_CREDENTIAL_NOT_FOUND, EDHOC_ERR_CRITICAL_EAD_UNSUPPORTED, EDHOC_ERR_CRYPTO_AUTHENTICATION, EDHOC_ERR_CRYPTO_DECRYPT, EDHOC_ERR_ID_CRED_MALFORMED, EDHOC_ERR_INTERNAL_ERROR, EDHOC_ERR_KEY_NOT_FOUND, EDHOC_ERR_METHOD_NOT_SUPPORTED, EDHOC_ERR_MSG_MALFORMED, EDHOC_ERR_NETWORK_TIMEOUT, EDHOC_ERR_NOT_ALLOWED_IDENTITY, EDHOC_ERR_SEQUENCE_ERROR, EDHOC_ERR_SUITE_NOT_SUPPORTED, EDHOC_ERR_WRONG_CID, and edhoc_serialize_err().

◆ edhoc_generate_id_cred_x()

size_t edhoc_generate_id_cred_x	(	const cose_key_t *	cose,
		uint8_t *	cred,
		size_t	cred_sz )

Generate credential identifier ID_CRED_X.

Parameters

cose	COSE key containing credential information
cred	Output buffer for credential ID
cred_sz	Output buffer size

Returns: Size of generated credential ID, 0 on error

Generates credential identifier (KID or full credential)

Definition at line 242 of file edhoc.c.

References cbor_close_map(), cbor_end_writer(), cbor_init_writer(), cbor_open_map(), cbor_write_data(), cbor_write_unsigned(), EDHOC_AUTHENT_TYPE, and edhoc_generate_cred_x().

Referenced by edhoc_authenticate_msg(), edhoc_generate_message_2(), and edhoc_generate_message_3().

◆ edhoc_generate_keystream_2e()

int16_t edhoc_generate_keystream_2e	(	edhoc_context_t *	ctx,
		uint16_t	length,
		uint8_t *	ks_2e )

Generate keystream KS_2e for encryption.

Parameters

ctx	EDHOC context
length	Keystream length
ks_2e	Output keystream buffer

Returns: 1 on success, negative on error

Derives keystream for encrypting/decrypting EDHOC message 2

Definition at line 561 of file edhoc.c.

References EDHOC_DBG_VALUE, and edhoc_kdf().

Referenced by edhoc_generate_message_2(), and edhoc_handler_msg_2().

◆ edhoc_generate_message_1()

edhoc_error_t edhoc_generate_message_1	(	edhoc_context_t *	ctx,
		uint8_t *	ad,
		size_t	ad_sz,
		bool	suite_array )

Generate the EDHOC Message 1 and set it in the EDHOC context.

Parameters

ctx	EDHOC Context struct
ad	Application data to include in MSG1
ad_sz	Application data length
suite_array	If true, MSG1 includes an array of cipher suites when more than one is supported. If false, MSG1 includes a single unsigned suite value regardless of the number of suites supported by the initiator.

Returns: EDHOC_SUCCESS on success, error code on failure

Composes EDHOC Message 1 as described in RFC9528 for EDHOC authentication with asymmetric keys, encoded as a CBOR sequence in the MSG1 element of the context struct. Uses the ephemeral key, cipher suite, and connection identifier already set in the context (they are established by the caller, not by this function). Used by the Initiator EDHOC role.

ctx->MSG1 = (METHOD:unsigned, SUITES_I, G_X, C_I_identifier)

Definition at line 199 of file edhoc-msg-generators.c.

References EDHOC_ERR_NULL_POINTER, EDHOC_ERR_SUITE_NOT_SUPPORTED, and EDHOC_SUITES_MAX_COUNT.

◆ edhoc_generate_message_2()

edhoc_error_t edhoc_generate_message_2	(	edhoc_context_t *	ctx,
		const uint8_t *	auth_data,
		size_t	auth_data_size )

Generate the EDHOC Message 2 and set it in the EDHOC context.

Parameters

ctx	EDHOC Context struct
auth_data	Application data to include in MSG2
auth_data_size	Application data length

Returns: EDHOC_SUCCESS on success, error code on failure

Used by the EDHOC Responder role to generate message 2. Computes the transcript hash TH_2 = H(ctx->MSG1, data_2), computes MAC_2 (Message Authentication Code), computes CIPHERTEXT_2, and composes EDHOC Message 2 as described in RFC9528 for EDHOC authentication with asymmetric keys, encoded as a CBOR sequence in the MSG2 element of the context struct. Uses the ephemeral key and connection identifier already set in the context.

ctx->MSG2 = a single CBOR byte string containing G_Y || CIPHERTEXT_2
where: data_2 = G_Y (C_R is carried inside the plaintext of CIPHERTEXT_2, not in data_2)

Definition at line 258 of file edhoc-msg-generators.c.

References cbor_close_data(), cbor_end_writer(), cbor_init_writer(), cbor_open_data(), cbor_write_data(), cbor_write_object(), cose_sign1_sign(), edhoc_enc_dec_ciphertext_2(), EDHOC_ERR_CBOR_ENCODING, EDHOC_ERR_CRYPTO_HASH, EDHOC_ERR_CRYPTO_SIGN, EDHOC_ERR_NULL_POINTER, edhoc_generate_cred_x(), edhoc_generate_id_cred_x(), edhoc_generate_keystream_2e(), edhoc_generate_prk_2e(), edhoc_generate_prk_3e2m(), edhoc_generate_transcript_hash_2(), EDHOC_MAC_OR_SIG_BUF_LEN, EDHOC_MAX_CRED_LEN, and edhoc_print_credential().

◆ edhoc_generate_message_3()

edhoc_error_t edhoc_generate_message_3	(	edhoc_context_t *	ctx,
		const uint8_t *	auth_data,
		size_t	auth_data_size )

Generate the EDHOC Message 3 and set it in the EDHOC context.

Parameters

ctx	EDHOC Context struct
auth_data	Application data to include in MSG3
auth_data_size	Application data length

Returns: EDHOC_SUCCESS on success, error code on failure

Used by the EDHOC Initiator role to generate message 3. Computes the transcript hash TH_3 = H(TH_2, PLAINTEXT_2, data_3), computes MAC_3 (Message Authentication Code), computes CIPHERTEXT_3, and composes EDHOC Message 3 as described in RFC9528 for EDHOC authentication with asymmetric keys, encoded as a CBOR sequence in the MSG3 element of the context struct.

ctx->MSG3 = (data_3, CIPHERTEXT_3)
where: data_3 = (?C_R_identifier)

Definition at line 406 of file edhoc-msg-generators.c.

References cbor_end_writer(), cbor_init_writer(), cbor_write_data(), cbor_write_object(), cose_print_key(), cose_sign1_sign(), EDHOC_ERR_BUFFER_TOO_SMALL, EDHOC_ERR_CRYPTO_ENCRYPT, EDHOC_ERR_CRYPTO_SIGN, EDHOC_ERR_NULL_POINTER, edhoc_generate_cred_x(), edhoc_generate_id_cred_x(), edhoc_generate_prk_4e3m(), edhoc_generate_transcript_hash_3(), edhoc_generate_transcript_hash_4(), EDHOC_MAC_OR_SIG_BUF_LEN, EDHOC_MAX_CRED_LEN, and edhoc_print_credential().

◆ edhoc_generate_prk_2e()

bool edhoc_generate_prk_2e ( edhoc_context_t * ctx )

Generate pseudorandom key PRK_2e.

Parameters

ctx	EDHOC context

Returns: true on success, false on failure

Generates PRK_2e using ECDH shared secret and TH_2

Definition at line 542 of file edhoc.c.

References ecdh_generate_ikm(), EDHOC_DBG_VALUE, and edhoc_trace_prk_derivation().

Referenced by edhoc_generate_message_2(), and edhoc_handler_msg_2().

◆ edhoc_generate_prk_3e2m()

bool edhoc_generate_prk_3e2m	(	edhoc_context_t *	ctx,
		const ecc_key_t *	auth_key,
		uint8_t	gen )

Generate pseudorandom key PRK_3e2m.

Parameters

ctx	EDHOC context
auth_key	Authentication key
gen	Key generation mode

Returns: true on success, false on failure

Generates PRK_3e2m using authentication key and ephemeral key

Referenced by edhoc_authenticate_msg(), and edhoc_generate_message_2().

◆ edhoc_generate_prk_4e3m()

bool edhoc_generate_prk_4e3m	(	edhoc_context_t *	ctx,
		const ecc_key_t *	auth_key,
		uint8_t	gen )

Generate pseudorandom key PRK_4e3m.

Parameters

ctx	EDHOC context
auth_key	Authentication key
gen	Key generation mode

Returns: true on success, false on failure

Generates PRK_4e3m using authentication key and ephemeral key

Referenced by edhoc_authenticate_msg(), and edhoc_generate_message_3().

◆ edhoc_generate_transcript_hash_2()

int8_t edhoc_generate_transcript_hash_2	(	edhoc_context_t *	ctx,
		const uint8_t *	eph_pub,
		uint8_t *	msg,
		uint16_t	msg_sz )

Generate transcript hash TH_2.

Parameters

ctx	EDHOC context
eph_pub	Ephemeral public key
msg	Message 1 buffer
msg_sz	Message 1 size

Returns: 0 on success, negative on error

Computes TH_2 = H(G_Y, H(message_1)) for EDHOC protocol

Definition at line 279 of file edhoc.c.

References cbor_end_writer(), cbor_init_writer(), cbor_write_data(), EDHOC_DBG_VALUE, edhoc_trace_transcript_hash(), and EDHOC_TRACE_VALUE.

Referenced by edhoc_generate_message_2(), and edhoc_handler_msg_2().

◆ edhoc_generate_transcript_hash_3()

uint8_t edhoc_generate_transcript_hash_3	(	edhoc_context_t *	ctx,
		const uint8_t *	cred,
		uint16_t	cred_sz,
		const uint8_t *	plaintext,
		uint16_t	plaintext_sz )

Generate transcript hash TH_3.

Parameters

ctx	EDHOC context
cred	Credential data
cred_sz	Credential size
plaintext	Plaintext data
plaintext_sz	Plaintext size

Returns: 0 on success, 1 on buffer overflow

Computes TH_3 = H(TH_2, PLAINTEXT_2, CRED_R) for EDHOC protocol

Definition at line 306 of file edhoc.c.

References cbor_end_writer(), cbor_init_writer(), cbor_write_data(), cbor_write_object(), EDHOC_DBG_VALUE, EDHOC_MAX_BUFFER, edhoc_trace_transcript_hash(), and EDHOC_TRACE_VALUE.

Referenced by edhoc_generate_message_3(), and edhoc_handler_msg_3().

◆ edhoc_generate_transcript_hash_4()

uint8_t edhoc_generate_transcript_hash_4	(	edhoc_context_t *	ctx,
		const uint8_t *	cred,
		uint16_t	cred_sz,
		const uint8_t *	plaintext,
		uint16_t	plaintext_sz )

Generate transcript hash TH_4.

Parameters

ctx	EDHOC context
cred	Credential data
cred_sz	Credential size
plaintext	Plaintext data
plaintext_sz	Plaintext size

Returns: 0 on success, 1 on buffer overflow

Computes TH_4 = H(TH_3, PLAINTEXT_3, CRED_I) for EDHOC protocol

Definition at line 335 of file edhoc.c.

References cbor_end_writer(), cbor_init_writer(), cbor_write_data(), cbor_write_object(), EDHOC_DBG_VALUE, EDHOC_MAX_BUFFER, edhoc_trace_transcript_hash(), and EDHOC_TRACE_VALUE.

Referenced by edhoc_authenticate_msg(), and edhoc_generate_message_3().

◆ edhoc_get_own_auth_key()

uint8_t edhoc_get_own_auth_key	(	edhoc_context_t *	ctx,
		cose_key_t **	key )

Retrieve own authentication key from key storage.

Parameters

ctx	EDHOC context
key	Pointer to store the found authentication key

Returns: 1 if key found, 0 if not found

Searches for authentication key using subject name or key ID

Definition at line 743 of file edhoc.c.

References edhoc_check_key_list_identity(), and edhoc_check_key_list_kid().

Referenced by edhoc_initialize_context().

◆ edhoc_initialize_context()

uint8_t edhoc_initialize_context ( edhoc_context_t * ctx )

Internal API functions.

Initialize the EDHOC context with default parameters

Parameters

ctx	EDHOC context to initialize

Returns: 1 on success, 0 on failure

Sets up cipher suites, authentication keys, connection ID, role, and method

Definition at line 688 of file edhoc.c.

References EDHOC_CID, EDHOC_DEFAULT_CID_LEN, edhoc_get_own_auth_key(), EDHOC_MAX_CID_LEN, EDHOC_METHOD, EDHOC_ROLE, edhoc_set_config_from_suite(), and edhoc_setup_suites().

Referenced by edhoc_server_reset_handshake().

◆ edhoc_kdf()

int16_t edhoc_kdf	(	const uint8_t *	prk,
		uint8_t	info_label,
		const uint8_t *	context,
		uint8_t	context_sz,
		uint16_t	length,
		uint8_t *	result )

EDHOC Key Derivation Function (KDF) based on HMAC-based Expand (RFC 5869).

Parameters

result	OKM (Output Keying Material) - the buffer where the derived key will be stored.
prk	PRK (Pseudorandom Key) - a pseudorandom key used as input to the key derivation, should be at least HASH_LEN bytes.
info_label	Label used to generate the CBOR-based info input for key derivation.
context	Context data used to generate the info input for key derivation.
context_sz	The size of the Context data.
length	Desired length of the output key material (OKM) in bytes.

Returns: The number of output key bytes generated (equal to length) on success, or 0 on failure.

This function combines the PRK, info_label, and context to generate an input info parameter that is used for HKDF-Expand as defined in RFC 5869. It is used by both the Initiator and Responder in the EDHOC protocol to generate keying material. Internally, this function calls edhoc_expand to compute the final OKM.

The function performs the following steps:

Calls generate_info to prepare the info input.
Passes the PRK, generated info, and length to edhoc_expand.

Example usage:

OKM = EDHOC_Expand(PRK, info, length)

Definition at line 373 of file edhoc.c.

References edhoc_expand().

Referenced by edhoc_calc_mac(), edhoc_exporter(), edhoc_exporter_oscore(), and edhoc_generate_keystream_2e().

◆ edhoc_print_config_summary()

void edhoc_print_config_summary ( const edhoc_context_t * ctx )

Print EDHOC session configuration summary.

Parameters

ctx	EDHOC context

Prints a comprehensive summary of the current EDHOC session configuration including role, method, cipher suite, and key information.

Definition at line 1003 of file edhoc.c.

◆ edhoc_print_session_info()

void edhoc_print_session_info ( const edhoc_context_t * ctx )

Print current EDHOC session information for debugging.

Parameters

ctx	EDHOC context

Logs session details including role, method, cipher suite, and connection IDs

Definition at line 366 of file edhoc.c.

References edhoc_trace_session_summary().

Referenced by edhoc_handler_msg_1().

◆ edhoc_set_config_from_suite()

int8_t edhoc_set_config_from_suite	(	edhoc_context_t *	ctx,
		uint8_t	suite )

Set EDHOC configuration parameters based on cipher suite.

Parameters

ctx	EDHOC context
suite	Selected cipher suite

Returns: 1 on success, 0 on failure

Configures ECDH curve, MAC length, AEAD algorithm, and signature algorithm

Definition at line 188 of file edhoc.c.

Referenced by edhoc_initialize_context().

◆ edhoc_setup_suites()

uint8_t edhoc_setup_suites ( edhoc_context_t * ctx )

Initialize the EDHOC Context with the defined EDHOC parameters.

Parameters

ctx	An EDHOC context struct to fill in

Returns: 1 on success, 0 if no supported cipher suites are configured

Used in the edhoc_new to set the default protocol definitions and in the Responder to reset the initial values to prepare for a new EDHOC connection. Sets up the cipher suites selection logic and validates that at least one cipher suite is supported.

Definition at line 89 of file edhoc.c.

References EDHOC_ERR_SUITE_NOT_SUPPORTED, and EDHOC_SUPPORTED_SUITE_1.

Referenced by edhoc_initialize_context(), and edhoc_server_reset_handshake().

◆ edhoc_storage_init()

void edhoc_storage_init ( void )

Reserve memory for the EDHOC context struct.

Used by both Initiator and Responder EDHOC roles to reserve memory

Definition at line 67 of file edhoc.c.

References memb_init().

Functions

Variables

Detailed Description

Function Documentation

◆ edhoc_authenticate_msg()

◆ edhoc_calc_mac()

◆ edhoc_enc_dec_ciphertext_2()

◆ edhoc_expand()

◆ edhoc_finalize()

◆ edhoc_generate_cred_x()

◆ edhoc_generate_error_message()

◆ edhoc_generate_id_cred_x()

◆ edhoc_generate_keystream_2e()

◆ edhoc_generate_message_1()

◆ edhoc_generate_message_2()

◆ edhoc_generate_message_3()

◆ edhoc_generate_prk_2e()

◆ edhoc_generate_prk_3e2m()

◆ edhoc_generate_prk_4e3m()

◆ edhoc_generate_transcript_hash_2()

◆ edhoc_generate_transcript_hash_3()

◆ edhoc_generate_transcript_hash_4()

◆ edhoc_get_own_auth_key()

◆ edhoc_initialize_context()

◆ edhoc_kdf()

◆ edhoc_print_config_summary()

◆ edhoc_print_session_info()

◆ edhoc_set_config_from_suite()

◆ edhoc_setup_suites()

◆ edhoc_storage_init()