ecdh.h File Reference

Elliptic curve Diffie-Hellman. More...

#include "ecp.h"

Include dependency graph for ecdh.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	ecdh_context
	ECDH context structure. More...

Enumerations
enum	ecdh_side { POLARSSL_ECDH_OURS, POLARSSL_ECDH_THEIRS }
	When importing from an EC key, select if it is our key or the peer's key. More...

Functions
int	ecdh_gen_public (ecp_group *grp, mpi *d, ecp_point *Q, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Generate a public key. More...
int	ecdh_compute_shared (ecp_group *grp, mpi *z, const ecp_point *Q, const mpi *d, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Compute shared secret Raw function that only does the core computation. More...
void	ecdh_init (ecdh_context *ctx)
	Initialize context. More...
void	ecdh_free (ecdh_context *ctx)
	Free context. More...
int	ecdh_make_params (ecdh_context *ctx, size_t *olen, unsigned char *buf, size_t blen, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Generate a public key and a TLS ServerKeyExchange payload. More...
int	ecdh_read_params (ecdh_context *ctx, const unsigned char **buf, const unsigned char *end)
	Parse and procress a TLS ServerKeyExhange payload. More...
int	ecdh_get_params (ecdh_context *ctx, const ecp_keypair *key, ecdh_side side)
	Setup an ECDH context from an EC key. More...
int	ecdh_make_public (ecdh_context *ctx, size_t *olen, unsigned char *buf, size_t blen, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Generate a public key and a TLS ClientKeyExchange payload. More...
int	ecdh_read_public (ecdh_context *ctx, const unsigned char *buf, size_t blen)
	Parse and process a TLS ClientKeyExchange payload. More...
int	ecdh_calc_secret (ecdh_context *ctx, size_t *olen, unsigned char *buf, size_t blen, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
	Derive and export the shared secret. More...
int	ecdh_self_test (int verbose)
	Checkup routine. More...

Detailed Description

Elliptic curve Diffie-Hellman.

Copyright (C) 2006-2013, Brainspark B.V.

This file is part of PolarSSL (http://www.polarssl.org) Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>

All rights reserved.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

Definition in file ecdh.h.

Enumeration Type Documentation

enum ecdh_side

When importing from an EC key, select if it is our key or the peer's key.

Enumerator
POLARSSL_ECDH_OURS
POLARSSL_ECDH_THEIRS

Definition at line 39 of file ecdh.h.

Function Documentation

int ecdh_calc_secret	(	ecdh_context *	ctx,
		size_t *	olen,
		unsigned char *	buf,
		size_t	blen,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Derive and export the shared secret.

(Last function used by both TLS client en servers.)

Parameters

ctx	ECDH context
olen	number of bytes written
buf	destination buffer
blen	buffer length
f_rng	RNG function, see notes for ecdh_compute_shared()
p_rng	RNG parameter

Returns

0 if successful, or an POLARSSL_ERR_ECP_XXX error code

int ecdh_compute_shared	(	ecp_group *	grp,
		mpi *	z,
		const ecp_point *	Q,
		const mpi *	d,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Compute shared secret Raw function that only does the core computation.

Parameters

grp	ECP group
z	Destination MPI (shared secret)
Q	Public key from other party
d	Our secret exponent (private key)
f_rng	RNG function (see notes)
p_rng	RNG parameter

Returns

0 if successful, or a POLARSSL_ERR_ECP_XXX or POLARSSL_MPI_XXX error code

Note

If f_rng is not NULL, it is used to implement countermeasures against potential elaborate timing attacks, see ecp_mul() for details.

void ecdh_free

(

ecdh_context *

ctx

)

Free context.

Parameters

ctx	Context to free

int ecdh_gen_public	(	ecp_group *	grp,
		mpi *	d,
		ecp_point *	Q,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Generate a public key.

Raw function that only does the core computation.

Parameters

grp	ECP group
d	Destination MPI (secret exponent, aka private key)
Q	Destination point (public key)
f_rng	RNG function
p_rng	RNG parameter

Returns

0 if successful, or a POLARSSL_ERR_ECP_XXX or POLARSSL_MPI_XXX error code

int ecdh_get_params	(	ecdh_context *	ctx,
		const ecp_keypair *	key,
		ecdh_side	side
	)

Setup an ECDH context from an EC key.

(Used by clients and servers in place of the ServerKeyEchange for static ECDH: import ECDH parameters from a certificate's EC key information.)

Parameters

ctx	ECDH constext to set
key	EC key to use
side	Is it our key (1) or the peer's key (0) ?

Returns

0 if successful, or an POLARSSL_ERR_ECP_XXX error code

void ecdh_init

(

ecdh_context *

ctx

)

Initialize context.

Parameters

ctx	Context to initialize

int ecdh_make_params	(	ecdh_context *	ctx,
		size_t *	olen,
		unsigned char *	buf,
		size_t	blen,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Generate a public key and a TLS ServerKeyExchange payload.

(First function used by a TLS server for ECDHE.)

Parameters

ctx	ECDH context
olen	number of chars written
buf	destination buffer
blen	length of buffer
f_rng	RNG function
p_rng	RNG parameter

Note

This function assumes that ctx->grp has already been properly set (for example using ecp_use_known_dp).

Returns

0 if successful, or an POLARSSL_ERR_ECP_XXX error code

int ecdh_make_public	(	ecdh_context *	ctx,
		size_t *	olen,
		unsigned char *	buf,
		size_t	blen,
		int(*)(void *, unsigned char *, size_t)	f_rng,
		void *	p_rng
	)

Generate a public key and a TLS ClientKeyExchange payload.

(Second function used by a TLS client for ECDH(E).)

Parameters

ctx	ECDH context
olen	number of bytes actually written
buf	destination buffer
blen	size of destination buffer
f_rng	RNG function
p_rng	RNG parameter

Returns

0 if successful, or an POLARSSL_ERR_ECP_XXX error code

int ecdh_read_params	(	ecdh_context *	ctx,
		const unsigned char **	buf,
		const unsigned char *	end
	)

Parse and procress a TLS ServerKeyExhange payload.

(First function used by a TLS client for ECDHE.)

Parameters

ctx	ECDH context
buf	pointer to start of input buffer
end	one past end of buffer

Returns

0 if successful, or an POLARSSL_ERR_ECP_XXX error code

int ecdh_read_public	(	ecdh_context *	ctx,
		const unsigned char *	buf,
		size_t	blen
	)

Parse and process a TLS ClientKeyExchange payload.

(Second function used by a TLS server for ECDH(E).)

Parameters

ctx	ECDH context
buf	start of input buffer
blen	length of input buffer

Returns

0 if successful, or an POLARSSL_ERR_ECP_XXX error code

int ecdh_self_test

(

int

verbose

)

Checkup routine.

Returns

0 if successful, or 1 if the test failed