library/ecjpake.c - security/mbedtls - Rivoreo Source Code Repositories

 /*
  *  Elliptic curve J-PAKE
  *
  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
  *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
  *  not use this file except in compliance with the License.
  *  You may obtain a copy of the License at
  *
  *  http://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing, software
  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
  */

 /*
  * We implement EC-JPAKE as defined in Chapter 7.4 of the Thread v1.0
  * Specification. References below are to this document.
  */

 #if !defined(MBEDTLS_CONFIG_FILE)
 #include "mbedtls/config.h"
 #else
 #include MBEDTLS_CONFIG_FILE
 #endif

 #if defined(MBEDTLS_ECJPAKE_C)

 #include "mbedtls/ecjpake.h"

 #include <string.h>

 /*
  * Write a point plus its length to a buffer
  */
 static int ecjpake_write_len_point( unsigned char **p,
                                     const unsigned char *end,
                                     const mbedtls_ecp_group *grp,
                                     const mbedtls_ecp_point *P )
 {
     int ret;
     size_t len;

     /* Need at least 4 for length plus 1 for point */
     if( end < *p || end - *p < 5 )
         return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

     ret = mbedtls_ecp_point_write_binary( grp, P, MBEDTLS_ECP_PF_UNCOMPRESSED,
                                           &len, *p + 4, end - ( *p + 4 ) );
     if( ret != 0 )
         return( ret );

     (*p)[0] = (unsigned char)( ( len >> 24 ) & 0xFF );
     (*p)[1] = (unsigned char)( ( len >> 16 ) & 0xFF );
     (*p)[2] = (unsigned char)( ( len >>  8 ) & 0xFF );
     (*p)[3] = (unsigned char)( ( len       ) & 0xFF );

     *p += 4 + len;

     return( 0 );
 }

 /*
  * Size of the temporary buffer for ecjpake_hash:
  * 3 EC points plus their length, plus ID (6 bytes)
  */
 #define ECJPAKE_HASH_BUF_LEN    ( 3 * ( 4 + MBEDTLS_ECP_MAX_PT_LEN ) + 6 )

 /*
  * Compute hash for ZKP (7.4.2.2.2.1)
  */
 static int ecjpake_hash( const mbedtls_md_info_t *md_info,
                          const mbedtls_ecp_group *grp,
                          const mbedtls_ecp_point *G,
                          const mbedtls_ecp_point *V,
                          const mbedtls_ecp_point *X,
                          const char *id,
                          mbedtls_mpi *h )
 {
     int ret;
     unsigned char buf[ECJPAKE_HASH_BUF_LEN];
     unsigned char *p = buf;
     const unsigned char *end = buf + sizeof( buf );
     const size_t id_len = strlen( id );
     unsigned char hash[MBEDTLS_MD_MAX_SIZE];

     /* Write things to temporary buffer */
     MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, G ) );
     MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, V ) );
     MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, X ) );

     if( end < p || (size_t)( end - p ) < id_len )
         return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

     *p++ = (unsigned char)( ( id_len >> 24 ) & 0xFF );
     *p++ = (unsigned char)( ( id_len >> 16 ) & 0xFF );
     *p++ = (unsigned char)( ( id_len >>  8 ) & 0xFF );
     *p++ = (unsigned char)( ( id_len       ) & 0xFF );

     memcpy( p, id, id_len );
     p += id_len;

     /* Compute hash */
     mbedtls_md( md_info, buf, p - buf, hash );

     /* Turn it into an integer mod n */
     MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( h, hash,
                                         mbedtls_md_get_size( md_info ) ) );
     MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( h, h, &grp->N ) );

 cleanup:
     return( ret );
 }

 /*
  * Generate ZKP (7.4.2.3.2) and write it as ECSchnorrZKP (7.4.2.2.2)
  */
 static int ecjpake_zkp_write( const mbedtls_md_info_t *md_info,
                               const mbedtls_ecp_group *grp,
                               const mbedtls_ecp_point *G,
                               const mbedtls_mpi *x,
                               const mbedtls_ecp_point *X,
                               const char *id,
                               unsigned char **p,
                               const unsigned char *end,
                               int (*f_rng)(void *, unsigned char *, size_t),
                               void *p_rng )
 {
     int ret;
     mbedtls_ecp_point V;
     mbedtls_mpi v;
     mbedtls_mpi h; /* later recycled to hold r */
     size_t len;

     if( end < *p )
         return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

     mbedtls_ecp_point_init( &V );
     mbedtls_mpi_init( &v );
     mbedtls_mpi_init( &h );

     /* Compute signature */
     MBEDTLS_MPI_CHK( mbedtls_ecp_gen_keypair_base( (mbedtls_ecp_group *) grp,
                                                    G, &v, &V, f_rng, p_rng ) );
     MBEDTLS_MPI_CHK( ecjpake_hash( md_info, grp, G, &V, X, id, &h ) );
     MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &h, &h, x ) ); /* x*h */
     MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &h, &v, &h ) ); /* v - x*h */
     MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &h, &h, &grp->N ) ); /* r */

     /* Write it out */
     MBEDTLS_MPI_CHK( mbedtls_ecp_tls_write_point( grp, &V,
                 MBEDTLS_ECP_PF_UNCOMPRESSED, &len, *p, end - *p ) );
     *p += len;

     len = mbedtls_mpi_size( &h ); /* actually r */
     if( end < *p || (size_t)( end - *p ) < 1 + len || len > 255 )
         return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

     *(*p)++ = (unsigned char)( len & 0xFF );
     MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &h, *p, len ) ); /* r */
     *p += len;

 cleanup:
     mbedtls_ecp_point_free( &V );
     mbedtls_mpi_free( &v );
     mbedtls_mpi_free( &h );

     return( ret );
 }

 /*
  * Parse a ECShnorrZKP (7.4.2.2.2) and verify it (7.4.2.3.3)
  */
 static int ecjpake_zkp_read( const mbedtls_md_info_t *md_info,
                              const mbedtls_ecp_group *grp,
                              const mbedtls_ecp_point *G,
                              const mbedtls_ecp_point *X,
                              const char *id,
                              unsigned char **p,
                              const unsigned char *end )
 {
     int ret;
     mbedtls_ecp_point V, VV;
     mbedtls_mpi r, h;
     size_t r_len;

     mbedtls_ecp_point_init( &V );
     mbedtls_ecp_point_init( &VV );
     mbedtls_mpi_init( &r );
     mbedtls_mpi_init( &h );

     /*
      * struct {
      *     ECPoint V;
      *     opaque r<1..2^8-1>;
      * } ECSchnorrZKP;
      */
     if( end < *p )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

     MBEDTLS_MPI_CHK( mbedtls_ecp_tls_read_point( grp, &V,
                      (const unsigned char **) p, end - *p ) );

     if( end < *p || (size_t)( end - *p ) < 1 )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

     r_len = *(*p)++;
     if( end < *p || (size_t)( end - *p ) < r_len )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

     MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &r, *p, r_len ) );
     *p += r_len;

     /*
      * Verification
      */
     MBEDTLS_MPI_CHK( ecjpake_hash( md_info, grp, G, &V, X, id, &h ) );
     MBEDTLS_MPI_CHK( mbedtls_ecp_muladd( (mbedtls_ecp_group *) grp,
                      &VV, &h, X, &r, G ) );

     if( mbedtls_ecp_point_cmp( &VV, &V ) != 0 )
         return( MBEDTLS_ERR_ECP_VERIFY_FAILED );

 cleanup:
     mbedtls_ecp_point_free( &V );
     mbedtls_ecp_point_free( &VV );
     mbedtls_mpi_free( &r );
     mbedtls_mpi_free( &h );

     return( ret );
 }


 #if defined(MBEDTLS_SELF_TEST)

 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
 #define mbedtls_printf     printf
 #endif

 #if !defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \
     !defined(MBEDTLS_SHA256_C)
 int mbedtls_ecjpake_self_test( int verbose )
 {
     (void) verbose;
     return( 0 );
 }
 #else

 static const unsigned char ecjpake_test_X[] = {
     0x04, 0xac, 0xcf, 0x01, 0x06, 0xef, 0x85, 0x8f, 0xa2, 0xd9, 0x19, 0x33,
     0x13, 0x46, 0x80, 0x5a, 0x78, 0xb5, 0x8b, 0xba, 0xd0, 0xb8, 0x44, 0xe5,
     0xc7, 0x89, 0x28, 0x79, 0x14, 0x61, 0x87, 0xdd, 0x26, 0x66, 0xad, 0xa7,
     0x81, 0xbb, 0x7f, 0x11, 0x13, 0x72, 0x25, 0x1a, 0x89, 0x10, 0x62, 0x1f,
     0x63, 0x4d, 0xf1, 0x28, 0xac, 0x48, 0xe3, 0x81, 0xfd, 0x6e, 0xf9, 0x06,
     0x07, 0x31, 0xf6, 0x94, 0xa4
 };

 static const unsigned char ecjpake_test_zkp[] = {
     0x41, 0x04, 0x1d, 0xd0, 0xbd, 0x5d, 0x45, 0x66, 0xc9, 0xbe, 0xd9, 0xce,
     0x7d, 0xe7, 0x01, 0xb5, 0xe8, 0x2e, 0x08, 0xe8, 0x4b, 0x73, 0x04, 0x66,
     0x01, 0x8a, 0xb9, 0x03, 0xc7, 0x9e, 0xb9, 0x82, 0x17, 0x22, 0x36, 0xc0,
     0xc1, 0x72, 0x8a, 0xe4, 0xbf, 0x73, 0x61, 0x0d, 0x34, 0xde, 0x44, 0x24,
     0x6e, 0xf3, 0xd9, 0xc0, 0x5a, 0x22, 0x36, 0xfb, 0x66, 0xa6, 0x58, 0x3d,
     0x74, 0x49, 0x30, 0x8b, 0xab, 0xce, 0x20, 0x72, 0xfe, 0x16, 0x66, 0x29,
     0x92, 0xe9, 0x23, 0x5c, 0x25, 0x00, 0x2f, 0x11, 0xb1, 0x50, 0x87, 0xb8,
     0x27, 0x38, 0xe0, 0x3c, 0x94, 0x5b, 0xf7, 0xa2, 0x99, 0x5d, 0xda, 0x1e,
     0x98, 0x34, 0x58
 };

 /* For tests we don't need a secure RNG;
  * use the LGC from Numerical Recipes for simplicity */
 static int ecjpake_lgc( void *p, unsigned char *out, size_t len )
 {
     static uint32_t x = 42;
     (void) p;

     while( len > 0 )
     {
         size_t use_len = len > 4 ? 4 : len;
         x = 1664525 * x + 1013904223;
         memcpy( out, &x, use_len );
         out += use_len;
         len -= use_len;
     }

     return( 0 );
 }

 /*
  * Checkup routine
  */
 int mbedtls_ecjpake_self_test( int verbose )
 {
     int ret;
     mbedtls_ecp_group grp;
     mbedtls_ecp_point X;
     mbedtls_mpi x;
     const mbedtls_md_info_t *md_info;
     unsigned char buf[1000];
     unsigned char *p;
     const unsigned char *end;

     mbedtls_ecp_group_init( &grp );
     mbedtls_ecp_point_init( &X );
     mbedtls_mpi_init( &x );

     /* Common to all tests */
     md_info = mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 );
     MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &grp, MBEDTLS_ECP_DP_SECP256R1 ) );

     if( verbose != 0 )
         mbedtls_printf( "  ECJPAKE test #1 (zkp read): " );

     MBEDTLS_MPI_CHK( mbedtls_ecp_point_read_binary( &grp, &X,
                                             ecjpake_test_X,
                                     sizeof( ecjpake_test_X ) ) );

     p = (unsigned char *) ecjpake_test_zkp;
     end = ecjpake_test_zkp + sizeof( ecjpake_test_zkp );
     MBEDTLS_MPI_CHK( ecjpake_zkp_read( md_info, &grp, &grp.G, &X, "client",
                                        &p, end ) );

     /* Corrupt proof */
     memcpy( buf, ecjpake_test_zkp, sizeof( ecjpake_test_zkp ) );
     buf[sizeof( ecjpake_test_zkp ) - 1]--;
     p = buf;
     end = buf + sizeof( ecjpake_test_zkp );
     ret = ecjpake_zkp_read( md_info, &grp, &grp.G, &X, "client", &p, end );

     if( ret != MBEDTLS_ERR_ECP_VERIFY_FAILED )
     {
         ret = 1;
         goto cleanup;
     }
     ret = 0;

     if( verbose != 0 )
         mbedtls_printf( "passed\n" );

     if( verbose != 0 )
         mbedtls_printf( "  ECJPAKE test #2 (zkp write/read): " );

     MBEDTLS_MPI_CHK( mbedtls_ecp_gen_keypair_base( &grp, &grp.G, &x, &X,
                                                    ecjpake_lgc, NULL ) );

     p = buf;
     MBEDTLS_MPI_CHK( ecjpake_zkp_write( md_info, &grp, &grp.G, &x, &X, "client",
                                         &p, buf + sizeof( buf ),
                                         ecjpake_lgc, NULL ) );

     p = buf;
     MBEDTLS_MPI_CHK( ecjpake_zkp_read( md_info, &grp, &grp.G, &X, "client",
                                        &p, buf + sizeof( buf ) ) );

     if( verbose != 0 )
         mbedtls_printf( "passed\n" );

 cleanup:
     mbedtls_ecp_group_free( &grp );
     mbedtls_ecp_point_free( &X );
     mbedtls_mpi_free( &x );

     if( ret != 0 )
     {
         if( verbose != 0 )
             mbedtls_printf( "failed\n" );

         ret = 1;
     }

     if( verbose != 0 )
         mbedtls_printf( "\n" );

     return( ret );
 }

 #endif /* MBEDTLS_ECP_DP_SECP256R1_ENABLED && MBEDTLS_SHA256_C */

 #endif /* MBEDTLS_SELF_TEST */

 #endif /* MBEDTLS_ECJPAKE_C */
	/*
	* Elliptic curve J-PAKE
	*
	* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
	* SPDX-License-Identifier: Apache-2.0
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may
	* not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	* This file is part of mbed TLS (https://tls.mbed.org)
	*/

	/*
	* We implement EC-JPAKE as defined in Chapter 7.4 of the Thread v1.0
	* Specification. References below are to this document.
	*/

	#if !defined(MBEDTLS_CONFIG_FILE)
	#include "mbedtls/config.h"
	#else
	#include MBEDTLS_CONFIG_FILE
	#endif

	#if defined(MBEDTLS_ECJPAKE_C)

	#include "mbedtls/ecjpake.h"

	#include <string.h>

	/*
	* Write a point plus its length to a buffer
	*/
	static int ecjpake_write_len_point( unsigned char **p,
	const unsigned char *end,
	const mbedtls_ecp_group *grp,
	const mbedtls_ecp_point *P )
	{
	int ret;
	size_t len;

	/* Need at least 4 for length plus 1 for point */
	if( end < p \|\| end - p < 5 )
	return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

	ret = mbedtls_ecp_point_write_binary( grp, P, MBEDTLS_ECP_PF_UNCOMPRESSED,
	&len, p + 4, end - ( p + 4 ) );
	if( ret != 0 )
	return( ret );

	(*p)[0] = (unsigned char)( ( len >> 24 ) & 0xFF );
	(*p)[1] = (unsigned char)( ( len >> 16 ) & 0xFF );
	(*p)[2] = (unsigned char)( ( len >> 8 ) & 0xFF );
	(*p)[3] = (unsigned char)( ( len ) & 0xFF );

	*p += 4 + len;

	return( 0 );
	}

	/*
	* Size of the temporary buffer for ecjpake_hash:
	* 3 EC points plus their length, plus ID (6 bytes)
	*/
	#define ECJPAKE_HASH_BUF_LEN ( 3 * ( 4 + MBEDTLS_ECP_MAX_PT_LEN ) + 6 )

	/*
	* Compute hash for ZKP (7.4.2.2.2.1)
	*/
	static int ecjpake_hash( const mbedtls_md_info_t *md_info,
	const mbedtls_ecp_group *grp,
	const mbedtls_ecp_point *G,
	const mbedtls_ecp_point *V,
	const mbedtls_ecp_point *X,
	const char *id,
	mbedtls_mpi *h )
	{
	int ret;
	unsigned char buf[ECJPAKE_HASH_BUF_LEN];
	unsigned char *p = buf;
	const unsigned char *end = buf + sizeof( buf );
	const size_t id_len = strlen( id );
	unsigned char hash[MBEDTLS_MD_MAX_SIZE];

	/* Write things to temporary buffer */
	MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, G ) );
	MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, V ) );
	MBEDTLS_MPI_CHK( ecjpake_write_len_point( &p, end, grp, X ) );

	if( end < p \|\| (size_t)( end - p ) < id_len )
	return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

	*p++ = (unsigned char)( ( id_len >> 24 ) & 0xFF );
	*p++ = (unsigned char)( ( id_len >> 16 ) & 0xFF );
	*p++ = (unsigned char)( ( id_len >> 8 ) & 0xFF );
	*p++ = (unsigned char)( ( id_len ) & 0xFF );

	memcpy( p, id, id_len );
	p += id_len;

	/* Compute hash */
	mbedtls_md( md_info, buf, p - buf, hash );

	/* Turn it into an integer mod n */
	MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( h, hash,
	mbedtls_md_get_size( md_info ) ) );
	MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( h, h, &grp->N ) );

	cleanup:
	return( ret );
	}

	/*
	* Generate ZKP (7.4.2.3.2) and write it as ECSchnorrZKP (7.4.2.2.2)
	*/
	static int ecjpake_zkp_write( const mbedtls_md_info_t *md_info,
	const mbedtls_ecp_group *grp,
	const mbedtls_ecp_point *G,
	const mbedtls_mpi *x,
	const mbedtls_ecp_point *X,
	const char *id,
	unsigned char **p,
	const unsigned char *end,
	int (f_rng)(void , unsigned char *, size_t),
	void *p_rng )
	{
	int ret;
	mbedtls_ecp_point V;
	mbedtls_mpi v;
	mbedtls_mpi h; /* later recycled to hold r */
	size_t len;

	if( end < *p )
	return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

	mbedtls_ecp_point_init( &V );
	mbedtls_mpi_init( &v );
	mbedtls_mpi_init( &h );

	/* Compute signature */
	MBEDTLS_MPI_CHK( mbedtls_ecp_gen_keypair_base( (mbedtls_ecp_group *) grp,
	G, &v, &V, f_rng, p_rng ) );
	MBEDTLS_MPI_CHK( ecjpake_hash( md_info, grp, G, &V, X, id, &h ) );
	MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &h, &h, x ) ); /* xh /
	MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &h, &v, &h ) ); /* v - xh /
	MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &h, &h, &grp->N ) ); /* r */

	/* Write it out */
	MBEDTLS_MPI_CHK( mbedtls_ecp_tls_write_point( grp, &V,
	MBEDTLS_ECP_PF_UNCOMPRESSED, &len, p, end - p ) );
	*p += len;

	len = mbedtls_mpi_size( &h ); /* actually r */
	if( end < p \|\| (size_t)( end - p ) < 1 + len \|\| len > 255 )
	return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );

	(p)++ = (unsigned char)( len & 0xFF );
	MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &h, p, len ) ); / r */
	*p += len;

	cleanup:
	mbedtls_ecp_point_free( &V );
	mbedtls_mpi_free( &v );
	mbedtls_mpi_free( &h );

	return( ret );
	}

	/*
	* Parse a ECShnorrZKP (7.4.2.2.2) and verify it (7.4.2.3.3)
	*/
	static int ecjpake_zkp_read( const mbedtls_md_info_t *md_info,
	const mbedtls_ecp_group *grp,
	const mbedtls_ecp_point *G,
	const mbedtls_ecp_point *X,
	const char *id,
	unsigned char **p,
	const unsigned char *end )
	{
	int ret;
	mbedtls_ecp_point V, VV;
	mbedtls_mpi r, h;
	size_t r_len;

	mbedtls_ecp_point_init( &V );
	mbedtls_ecp_point_init( &VV );
	mbedtls_mpi_init( &r );
	mbedtls_mpi_init( &h );

	/*
	* struct {
	* ECPoint V;
	* opaque r<1..2^8-1>;
	* } ECSchnorrZKP;
	*/
	if( end < *p )
	return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

	MBEDTLS_MPI_CHK( mbedtls_ecp_tls_read_point( grp, &V,
	(const unsigned char *) p, end - p ) );

	if( end < p \|\| (size_t)( end - p ) < 1 )
	return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

	r_len = (p)++;
	if( end < p \|\| (size_t)( end - p ) < r_len )
	return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

	MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &r, *p, r_len ) );
	*p += r_len;

	/*
	* Verification
	*/
	MBEDTLS_MPI_CHK( ecjpake_hash( md_info, grp, G, &V, X, id, &h ) );
	MBEDTLS_MPI_CHK( mbedtls_ecp_muladd( (mbedtls_ecp_group *) grp,
	&VV, &h, X, &r, G ) );

	if( mbedtls_ecp_point_cmp( &VV, &V ) != 0 )
	return( MBEDTLS_ERR_ECP_VERIFY_FAILED );

	cleanup:
	mbedtls_ecp_point_free( &V );
	mbedtls_ecp_point_free( &VV );
	mbedtls_mpi_free( &r );
	mbedtls_mpi_free( &h );

	return( ret );
	}


	#if defined(MBEDTLS_SELF_TEST)

	#if defined(MBEDTLS_PLATFORM_C)
	#include "mbedtls/platform.h"
	#else
	#include <stdio.h>
	#define mbedtls_printf printf
	#endif

	#if !defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) \|\| \
	!defined(MBEDTLS_SHA256_C)
	int mbedtls_ecjpake_self_test( int verbose )
	{
	(void) verbose;
	return( 0 );
	}
	#else

	static const unsigned char ecjpake_test_X[] = {
	0x04, 0xac, 0xcf, 0x01, 0x06, 0xef, 0x85, 0x8f, 0xa2, 0xd9, 0x19, 0x33,
	0x13, 0x46, 0x80, 0x5a, 0x78, 0xb5, 0x8b, 0xba, 0xd0, 0xb8, 0x44, 0xe5,
	0xc7, 0x89, 0x28, 0x79, 0x14, 0x61, 0x87, 0xdd, 0x26, 0x66, 0xad, 0xa7,
	0x81, 0xbb, 0x7f, 0x11, 0x13, 0x72, 0x25, 0x1a, 0x89, 0x10, 0x62, 0x1f,
	0x63, 0x4d, 0xf1, 0x28, 0xac, 0x48, 0xe3, 0x81, 0xfd, 0x6e, 0xf9, 0x06,
	0x07, 0x31, 0xf6, 0x94, 0xa4
	};

	static const unsigned char ecjpake_test_zkp[] = {
	0x41, 0x04, 0x1d, 0xd0, 0xbd, 0x5d, 0x45, 0x66, 0xc9, 0xbe, 0xd9, 0xce,
	0x7d, 0xe7, 0x01, 0xb5, 0xe8, 0x2e, 0x08, 0xe8, 0x4b, 0x73, 0x04, 0x66,
	0x01, 0x8a, 0xb9, 0x03, 0xc7, 0x9e, 0xb9, 0x82, 0x17, 0x22, 0x36, 0xc0,
	0xc1, 0x72, 0x8a, 0xe4, 0xbf, 0x73, 0x61, 0x0d, 0x34, 0xde, 0x44, 0x24,
	0x6e, 0xf3, 0xd9, 0xc0, 0x5a, 0x22, 0x36, 0xfb, 0x66, 0xa6, 0x58, 0x3d,
	0x74, 0x49, 0x30, 0x8b, 0xab, 0xce, 0x20, 0x72, 0xfe, 0x16, 0x66, 0x29,
	0x92, 0xe9, 0x23, 0x5c, 0x25, 0x00, 0x2f, 0x11, 0xb1, 0x50, 0x87, 0xb8,
	0x27, 0x38, 0xe0, 0x3c, 0x94, 0x5b, 0xf7, 0xa2, 0x99, 0x5d, 0xda, 0x1e,
	0x98, 0x34, 0x58
	};

	/* For tests we don't need a secure RNG;
	* use the LGC from Numerical Recipes for simplicity */
	static int ecjpake_lgc( void p, unsigned char out, size_t len )
	{
	static uint32_t x = 42;
	(void) p;

	while( len > 0 )
	{
	size_t use_len = len > 4 ? 4 : len;
	x = 1664525 * x + 1013904223;
	memcpy( out, &x, use_len );
	out += use_len;
	len -= use_len;
	}

	return( 0 );
	}

	/*
	* Checkup routine
	*/
	int mbedtls_ecjpake_self_test( int verbose )
	{
	int ret;
	mbedtls_ecp_group grp;
	mbedtls_ecp_point X;
	mbedtls_mpi x;
	const mbedtls_md_info_t *md_info;
	unsigned char buf[1000];
	unsigned char *p;
	const unsigned char *end;

	mbedtls_ecp_group_init( &grp );
	mbedtls_ecp_point_init( &X );
	mbedtls_mpi_init( &x );

	/* Common to all tests */
	md_info = mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 );
	MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &grp, MBEDTLS_ECP_DP_SECP256R1 ) );

	if( verbose != 0 )
	mbedtls_printf( " ECJPAKE test #1 (zkp read): " );

	MBEDTLS_MPI_CHK( mbedtls_ecp_point_read_binary( &grp, &X,
	ecjpake_test_X,
	sizeof( ecjpake_test_X ) ) );

	p = (unsigned char *) ecjpake_test_zkp;
	end = ecjpake_test_zkp + sizeof( ecjpake_test_zkp );
	MBEDTLS_MPI_CHK( ecjpake_zkp_read( md_info, &grp, &grp.G, &X, "client",
	&p, end ) );

	/* Corrupt proof */
	memcpy( buf, ecjpake_test_zkp, sizeof( ecjpake_test_zkp ) );
	buf[sizeof( ecjpake_test_zkp ) - 1]--;
	p = buf;
	end = buf + sizeof( ecjpake_test_zkp );
	ret = ecjpake_zkp_read( md_info, &grp, &grp.G, &X, "client", &p, end );

	if( ret != MBEDTLS_ERR_ECP_VERIFY_FAILED )
	{
	ret = 1;
	goto cleanup;
	}
	ret = 0;

	if( verbose != 0 )
	mbedtls_printf( "passed\n" );

	if( verbose != 0 )
	mbedtls_printf( " ECJPAKE test #2 (zkp write/read): " );

	MBEDTLS_MPI_CHK( mbedtls_ecp_gen_keypair_base( &grp, &grp.G, &x, &X,
	ecjpake_lgc, NULL ) );

	p = buf;
	MBEDTLS_MPI_CHK( ecjpake_zkp_write( md_info, &grp, &grp.G, &x, &X, "client",
	&p, buf + sizeof( buf ),
	ecjpake_lgc, NULL ) );

	p = buf;
	MBEDTLS_MPI_CHK( ecjpake_zkp_read( md_info, &grp, &grp.G, &X, "client",
	&p, buf + sizeof( buf ) ) );

	if( verbose != 0 )
	mbedtls_printf( "passed\n" );

	cleanup:
	mbedtls_ecp_group_free( &grp );
	mbedtls_ecp_point_free( &X );
	mbedtls_mpi_free( &x );

	if( ret != 0 )
	{
	if( verbose != 0 )
	mbedtls_printf( "failed\n" );

	ret = 1;
	}

	if( verbose != 0 )
	mbedtls_printf( "\n" );

	return( ret );
	}

	#endif /* MBEDTLS_ECP_DP_SECP256R1_ENABLED && MBEDTLS_SHA256_C */

	#endif /* MBEDTLS_SELF_TEST */

	#endif /* MBEDTLS_ECJPAKE_C */