ecdh.h File Reference

Elliptic curve Diffie-Hellman. More...

#include "ecp.h"

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Data Structures
struct	ecdh_context
	ECDH context structure. 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.
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.
void	ecdh_init (ecdh_context *ctx)
	Initialize context.
void	ecdh_free (ecdh_context *ctx)
	Free context.
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)
	Setup and write the ServerKeyExhange parameters.
int	ecdh_read_params (ecdh_context *ctx, const unsigned char **buf, const unsigned char *end)
	Parse the ServerKeyExhange parameters.
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)
	Setup and export the client's public value.
int	ecdh_read_public (ecdh_context *ctx, const unsigned char *buf, size_t blen)
	Parse and import the client's public value.
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.
int	ecdh_self_test (int verbose)
	Checkup routine.

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.

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.

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.

Parameters

grp	ECP group
z	Destination MPI (shared secret)
Q	Public key from other party
d	Our secret exponent
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.

Parameters

grp	ECP group
d	Destination MPI (secret exponent)
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

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
	)

Setup and write the ServerKeyExhange parameters.

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
	)

Setup and export the client's public value.

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 the ServerKeyExhange parameters.

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 import the client's public value.

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