Elliptic Curve J-PAKE

Data Structures
struct	mbedtls_ecjpake_context
	EC J-PAKE context structure. More...

Typedefs
typedef struct mbedtls_ecjpake_context	mbedtls_ecjpake_context
	EC J-PAKE context structure. More...

Enumerations
enum	mbedtls_ecjpake_role { MBEDTLS_ECJPAKE_CLIENT = 0 , MBEDTLS_ECJPAKE_SERVER }
	Roles in the EC J-PAKE exchange. More...

Functions
void	mbedtls_ecjpake_init (mbedtls_ecjpake_context *ctx)
	Initialize an ECJPAKE context. More...
int	mbedtls_ecjpake_setup (mbedtls_ecjpake_context *ctx, mbedtls_ecjpake_role role, mbedtls_md_type_t hash, mbedtls_ecp_group_id curve, const unsigned char *secret, size_t len)
	Set up an ECJPAKE context for use. More...
int	mbedtls_ecjpake_check (const mbedtls_ecjpake_context *ctx)
	Check if an ECJPAKE context is ready for use. More...
int	mbedtls_ecjpake_write_round_one (mbedtls_ecjpake_context *ctx, unsigned char *buf, size_t len, size_t *olen, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Generate and write the first round message (TLS: contents of the Client/ServerHello extension, excluding extension type and length bytes). More...
int	mbedtls_ecjpake_read_round_one (mbedtls_ecjpake_context *ctx, const unsigned char *buf, size_t len)
	Read and process the first round message (TLS: contents of the Client/ServerHello extension, excluding extension type and length bytes). More...
int	mbedtls_ecjpake_write_round_two (mbedtls_ecjpake_context *ctx, unsigned char *buf, size_t len, size_t *olen, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Generate and write the second round message (TLS: contents of the Client/ServerKeyExchange). More...
int	mbedtls_ecjpake_read_round_two (mbedtls_ecjpake_context *ctx, const unsigned char *buf, size_t len)
	Read and process the second round message (TLS: contents of the Client/ServerKeyExchange). More...
int	mbedtls_ecjpake_derive_secret (mbedtls_ecjpake_context *ctx, unsigned char *buf, size_t len, size_t *olen, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Derive the shared secret (TLS: Pre-Master Secret). More...
void	mbedtls_ecjpake_free (mbedtls_ecjpake_context *ctx)
	This clears an ECJPAKE context and frees any embedded data structure. More...

Detailed Description

Typedef Documentation

mbedtls_ecjpake_context

typedef struct mbedtls_ecjpake_context mbedtls_ecjpake_context

EC J-PAKE context structure.

J-PAKE is a symmetric protocol, except for the identifiers used in Zero-Knowledge Proofs, and the serialization of the second message (KeyExchange) as defined by the Thread spec.

In order to benefit from this symmetry, we choose a different naming convetion from the Thread v1.0 spec. Correspondance is indicated in the description as a pair C: client name, S: server name

Enumeration Type Documentation

mbedtls_ecjpake_role

enum mbedtls_ecjpake_role

Roles in the EC J-PAKE exchange.

Enumerator
MBEDTLS_ECJPAKE_CLIENT	Client
MBEDTLS_ECJPAKE_SERVER	Server

Definition at line 64 of file ecjpake.h.

Function Documentation

mbedtls_ecjpake_init()

void mbedtls_ecjpake_init

(

mbedtls_ecjpake_context *

ctx

)

Initialize an ECJPAKE context.

Parameters

ctx	The ECJPAKE context to initialize. This must not be NULL.

mbedtls_ecjpake_setup()

int mbedtls_ecjpake_setup	(	mbedtls_ecjpake_context *	ctx,
		mbedtls_ecjpake_role	role,
		mbedtls_md_type_t	hash,
		mbedtls_ecp_group_id	curve,
		const unsigned char *	secret,
		size_t	len
	)

Set up an ECJPAKE context for use.

Note

Currently the only values for hash/curve allowed by the standard are MBEDTLS_MD_SHA256/MBEDTLS_ECP_DP_SECP256R1.

Parameters

ctx	The ECJPAKE context to set up. This must be initialized.
role	The role of the caller. This must be either MBEDTLS_ECJPAKE_CLIENT or MBEDTLS_ECJPAKE_SERVER.
hash	The identifier of the hash function to use, for example MBEDTLS_MD_SHA256.
curve	The identifier of the elliptic curve to use, for example MBEDTLS_ECP_DP_SECP256R1.
secret	The pre-shared secret (passphrase). This must be a readable buffer of length len Bytes. It need only be valid for the duration of this call.
len	The length of the pre-shared secret secret.

Returns

0 if successful.

A negative error code on failure.

mbedtls_ecjpake_check()

int mbedtls_ecjpake_check

(

const mbedtls_ecjpake_context *

ctx

)

Check if an ECJPAKE context is ready for use.

Parameters

ctx	The ECJPAKE context to check. This must be initialized.

Returns

0 if the context is ready for use.

MBEDTLS_ERR_ECP_BAD_INPUT_DATA otherwise.

mbedtls_ecjpake_write_round_one()

int mbedtls_ecjpake_write_round_one	(	mbedtls_ecjpake_context *	ctx,
		unsigned char *	buf,
		size_t	len,
		size_t *	olen,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Generate and write the first round message (TLS: contents of the Client/ServerHello extension, excluding extension type and length bytes).

Parameters

ctx	The ECJPAKE context to use. This must be initialized and set up.
buf	The buffer to write the contents to. This must be a writable buffer of length len Bytes.
len	The length of buf in Bytes.
olen	The address at which to store the total number of Bytes written to buf. This must not be NULL.
f_rng	The RNG function to use. This must not be NULL.
p_rng	The RNG parameter to be passed to f_rng. This may be NULL if f_rng doesn't use a context.

Returns

0 if successful.

A negative error code on failure.

mbedtls_ecjpake_read_round_one()

int mbedtls_ecjpake_read_round_one	(	mbedtls_ecjpake_context *	ctx,
		const unsigned char *	buf,
		size_t	len
	)

Read and process the first round message (TLS: contents of the Client/ServerHello extension, excluding extension type and length bytes).

Parameters

ctx	The ECJPAKE context to use. This must be initialized and set up.
buf	The buffer holding the first round message. This must be a readable buffer of length len Bytes.
len	The length in Bytes of buf.

Returns

0 if successful.

A negative error code on failure.

mbedtls_ecjpake_write_round_two()

int mbedtls_ecjpake_write_round_two	(	mbedtls_ecjpake_context *	ctx,
		unsigned char *	buf,
		size_t	len,
		size_t *	olen,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Generate and write the second round message (TLS: contents of the Client/ServerKeyExchange).

Parameters

ctx	The ECJPAKE context to use. This must be initialized, set up, and already have performed round one.
buf	The buffer to write the round two contents to. This must be a writable buffer of length len Bytes.
len	The size of buf in Bytes.
olen	The address at which to store the total number of Bytes written to buf. This must not be NULL.
f_rng	The RNG function to use. This must not be NULL.
p_rng	The RNG parameter to be passed to f_rng. This may be NULL if f_rng doesn't use a context.

Returns

0 if successful.

A negative error code on failure.

mbedtls_ecjpake_read_round_two()

int mbedtls_ecjpake_read_round_two	(	mbedtls_ecjpake_context *	ctx,
		const unsigned char *	buf,
		size_t	len
	)

Read and process the second round message (TLS: contents of the Client/ServerKeyExchange).

Parameters

ctx	The ECJPAKE context to use. This must be initialized and set up and already have performed round one.
buf	The buffer holding the second round message. This must be a readable buffer of length len Bytes.
len	The length in Bytes of buf.

Returns

0 if successful.

A negative error code on failure.

mbedtls_ecjpake_derive_secret()

int mbedtls_ecjpake_derive_secret	(	mbedtls_ecjpake_context *	ctx,
		unsigned char *	buf,
		size_t	len,
		size_t *	olen,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Derive the shared secret (TLS: Pre-Master Secret).

Parameters

ctx	The ECJPAKE context to use. This must be initialized, set up and have performed both round one and two.
buf	The buffer to write the derived secret to. This must be a writable buffer of length len Bytes.
len	The length of buf in Bytes.
olen	The address at which to store the total number of Bytes written to buf. This must not be NULL.
f_rng	The RNG function to use. This must not be NULL.
p_rng	The RNG parameter to be passed to f_rng. This may be NULL if f_rng doesn't use a context.

Returns

0 if successful.

A negative error code on failure.

mbedtls_ecjpake_free()

void mbedtls_ecjpake_free

(

mbedtls_ecjpake_context *

ctx

)

This clears an ECJPAKE context and frees any embedded data structure.

Parameters

ctx	The ECJPAKE context to free. This may be NULL, in which case this function does nothing. If it is not NULL, it must point to an initialized ECJPAKE context.