/** * \file ecjpake.h * * \brief Elliptic curve J-PAKE */ /* * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved * SPDX-License-Identifier: GPL-2.0 * * 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. * * This file is part of mbed TLS (https://tls.mbed.org) */ #ifndef MBEDTLS_ECJPAKE_H #define MBEDTLS_ECJPAKE_H /* * J-PAKE is a password-authenticated key exchange that allows deriving a * strong shared secret from a (potentially low entropy) pre-shared * passphrase, with forward secrecy and mutual authentication. * https://en.wikipedia.org/wiki/Password_Authenticated_Key_Exchange_by_Juggling * * This file implements the Elliptic Curve variant of J-PAKE, * as defined in Chapter 7.4 of the Thread v1.0 Specification, * available to members of the Thread Group http://threadgroup.org/ * * As the J-PAKE algorithm is inherently symmetric, so is our API. * Each party needs to send its first round message, in any order, to the * other party, then each sends its second round message, in any order. * The payloads are serialized in a way suitable for use in TLS, but could * also be use outside TLS. */ #if !defined(MBEDTLS_CONFIG_FILE) #include "config.h" #else #include MBEDTLS_CONFIG_FILE #endif #include "ecp.h" #include "md.h" #if !defined(MBEDTLS_ECJPAKE_ALT) #ifdef __cplusplus extern "C" { #endif /** * Roles in the EC J-PAKE exchange */ typedef enum { MBEDTLS_ECJPAKE_CLIENT = 0, /**< Client */ MBEDTLS_ECJPAKE_SERVER, /**< Server */ } mbedtls_ecjpake_role; /** * 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 */ typedef struct { const mbedtls_md_info_t *md_info; /**< Hash to use */ mbedtls_ecp_group grp; /**< Elliptic curve */ mbedtls_ecjpake_role role; /**< Are we client or server? */ int point_format; /**< Format for point export */ mbedtls_ecp_point Xm1; /**< My public key 1 C: X1, S: X3 */ mbedtls_ecp_point Xm2; /**< My public key 2 C: X2, S: X4 */ mbedtls_ecp_point Xp1; /**< Peer public key 1 C: X3, S: X1 */ mbedtls_ecp_point Xp2; /**< Peer public key 2 C: X4, S: X2 */ mbedtls_ecp_point Xp; /**< Peer public key C: Xs, S: Xc */ mbedtls_mpi xm1; /**< My private key 1 C: x1, S: x3 */ mbedtls_mpi xm2; /**< My private key 2 C: x2, S: x4 */ mbedtls_mpi s; /**< Pre-shared secret (passphrase) */ } mbedtls_ecjpake_context; /** * \brief Initialize a context * (just makes it ready for setup() or free()). * * \param ctx context to initialize */ void mbedtls_ecjpake_init( mbedtls_ecjpake_context *ctx ); /** * \brief Set up a context for use * * \note Currently the only values for hash/curve allowed by the * standard are MBEDTLS_MD_SHA256/MBEDTLS_ECP_DP_SECP256R1. * * \param ctx context to set up * \param role Our role: client or server * \param hash hash function to use (MBEDTLS_MD_XXX) * \param curve elliptic curve identifier (MBEDTLS_ECP_DP_XXX) * \param secret pre-shared secret (passphrase) * \param len length of the shared secret * * \return 0 if successfull, * a negative error code otherwise */ 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 ); /** * \brief Check if a context is ready for use * * \param ctx Context to check * * \return 0 if the context is ready for use, * MBEDTLS_ERR_ECP_BAD_INPUT_DATA otherwise */ int mbedtls_ecjpake_check( const mbedtls_ecjpake_context *ctx ); /** * \brief Generate and write the first round message * (TLS: contents of the Client/ServerHello extension, * excluding extension type and length bytes) * * \param ctx Context to use * \param buf Buffer to write the contents to * \param len Buffer size * \param olen Will be updated with the number of bytes written * \param f_rng RNG function * \param p_rng RNG parameter * * \return 0 if successfull, * a negative error code otherwise */ 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 ); /** * \brief Read and process the first round message * (TLS: contents of the Client/ServerHello extension, * excluding extension type and length bytes) * * \param ctx Context to use * \param buf Pointer to extension contents * \param len Extension length * * \return 0 if successfull, * a negative error code otherwise */ int mbedtls_ecjpake_read_round_one( mbedtls_ecjpake_context *ctx, const unsigned char *buf, size_t len ); /** * \brief Generate and write the second round message * (TLS: contents of the Client/ServerKeyExchange) * * \param ctx Context to use * \param buf Buffer to write the contents to * \param len Buffer size * \param olen Will be updated with the number of bytes written * \param f_rng RNG function * \param p_rng RNG parameter * * \return 0 if successfull, * a negative error code otherwise */ 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 ); /** * \brief Read and process the second round message * (TLS: contents of the Client/ServerKeyExchange) * * \param ctx Context to use * \param buf Pointer to the message * \param len Message length * * \return 0 if successfull, * a negative error code otherwise */ int mbedtls_ecjpake_read_round_two( mbedtls_ecjpake_context *ctx, const unsigned char *buf, size_t len ); /** * \brief Derive the shared secret * (TLS: Pre-Master Secret) * * \param ctx Context to use * \param buf Buffer to write the contents to * \param len Buffer size * \param olen Will be updated with the number of bytes written * \param f_rng RNG function * \param p_rng RNG parameter * * \return 0 if successfull, * a negative error code otherwise */ 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 ); /** * \brief Free a context's content * * \param ctx context to free */ void mbedtls_ecjpake_free( mbedtls_ecjpake_context *ctx ); #ifdef __cplusplus } #endif #else /* MBEDTLS_ECJPAKE_ALT */ #include "ecjpake_alt.h" #endif /* MBEDTLS_ECJPAKE_ALT */ #if defined(MBEDTLS_SELF_TEST) #ifdef __cplusplus extern "C" { #endif /** * \brief Checkup routine * * \return 0 if successful, or 1 if a test failed */ int mbedtls_ecjpake_self_test( int verbose ); #ifdef __cplusplus } #endif #endif /* MBEDTLS_SELF_TEST */ #endif /* ecjpake.h */