| /** |
| * \file ecjpake.h |
| * |
| * \brief Elliptic curve J-PAKE |
| */ |
| /* |
| * Copyright The Mbed TLS Contributors |
| * 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. |
| */ |
| #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 "mbedtls/config.h" |
| #else |
| #include MBEDTLS_CONFIG_FILE |
| #endif |
| |
| #include "mbedtls/ecp.h" |
| #include "mbedtls/md.h" |
| |
| #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; |
| |
| #if !defined(MBEDTLS_ECJPAKE_ALT) |
| /** |
| * 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 |
| * convention from the Thread v1.0 spec. Correspondence is indicated in the |
| * description as a pair C: client name, S: server name |
| */ |
| typedef struct mbedtls_ecjpake_context { |
| 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; |
| |
| #else /* MBEDTLS_ECJPAKE_ALT */ |
| #include "ecjpake_alt.h" |
| #endif /* MBEDTLS_ECJPAKE_ALT */ |
| |
| /** |
| * \brief Initialize an ECJPAKE context. |
| * |
| * \param ctx The ECJPAKE context to initialize. |
| * This must not be \c NULL. |
| */ |
| void mbedtls_ecjpake_init(mbedtls_ecjpake_context *ctx); |
| |
| /** |
| * \brief 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. |
| * |
| * \param ctx The ECJPAKE context to set up. This must be initialized. |
| * \param role The role of the caller. This must be either |
| * #MBEDTLS_ECJPAKE_CLIENT or #MBEDTLS_ECJPAKE_SERVER. |
| * \param hash The identifier of the hash function to use, |
| * for example #MBEDTLS_MD_SHA256. |
| * \param curve The identifier of the elliptic curve to use, |
| * for example #MBEDTLS_ECP_DP_SECP256R1. |
| * \param secret The pre-shared secret (passphrase). This must be |
| * a readable buffer of length \p len Bytes. It need |
| * only be valid for the duration of this call. |
| * \param len The length of the pre-shared secret \p secret. |
| * |
| * \return \c 0 if successful. |
| * \return A negative error code on failure. |
| */ |
| 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 an ECJPAKE context is ready for use. |
| * |
| * \param ctx The ECJPAKE context to check. This must be |
| * initialized. |
| * |
| * \return \c 0 if the context is ready for use. |
| * \return #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 The ECJPAKE context to use. This must be |
| * initialized and set up. |
| * \param buf The buffer to write the contents to. This must be a |
| * writable buffer of length \p len Bytes. |
| * \param len The length of \p buf in Bytes. |
| * \param olen The address at which to store the total number |
| * of Bytes written to \p buf. This must not be \c NULL. |
| * \param f_rng The RNG function to use. This must not be \c NULL. |
| * \param p_rng The RNG parameter to be passed to \p f_rng. This |
| * may be \c NULL if \p f_rng doesn't use a context. |
| * |
| * \return \c 0 if successful. |
| * \return A negative error code on failure. |
| */ |
| 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 The ECJPAKE context to use. This must be initialized |
| * and set up. |
| * \param buf The buffer holding the first round message. This must |
| * be a readable buffer of length \p len Bytes. |
| * \param len The length in Bytes of \p buf. |
| * |
| * \return \c 0 if successful. |
| * \return A negative error code on failure. |
| */ |
| 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 The ECJPAKE context to use. This must be initialized, |
| * set up, and already have performed round one. |
| * \param buf The buffer to write the round two contents to. |
| * This must be a writable buffer of length \p len Bytes. |
| * \param len The size of \p buf in Bytes. |
| * \param olen The address at which to store the total number of Bytes |
| * written to \p buf. This must not be \c NULL. |
| * \param f_rng The RNG function to use. This must not be \c NULL. |
| * \param p_rng The RNG parameter to be passed to \p f_rng. This |
| * may be \c NULL if \p f_rng doesn't use a context. |
| * |
| * \return \c 0 if successful. |
| * \return A negative error code on failure. |
| */ |
| 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 The ECJPAKE context to use. This must be initialized |
| * and set up and already have performed round one. |
| * \param buf The buffer holding the second round message. This must |
| * be a readable buffer of length \p len Bytes. |
| * \param len The length in Bytes of \p buf. |
| * |
| * \return \c 0 if successful. |
| * \return A negative error code on failure. |
| */ |
| 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 The ECJPAKE context to use. This must be initialized, |
| * set up and have performed both round one and two. |
| * \param buf The buffer to write the derived secret to. This must |
| * be a writable buffer of length \p len Bytes. |
| * \param len The length of \p buf in Bytes. |
| * \param olen The address at which to store the total number of Bytes |
| * written to \p buf. This must not be \c NULL. |
| * \param f_rng The RNG function to use. This must not be \c NULL. |
| * \param p_rng The RNG parameter to be passed to \p f_rng. This |
| * may be \c NULL if \p f_rng doesn't use a context. |
| * |
| * \return \c 0 if successful. |
| * \return A negative error code on failure. |
| */ |
| 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 This clears an ECJPAKE context and frees any |
| * embedded data structure. |
| * |
| * \param ctx The ECJPAKE context to free. This may be \c NULL, |
| * in which case this function does nothing. If it is not |
| * \c NULL, it must point to an initialized ECJPAKE context. |
| */ |
| void mbedtls_ecjpake_free(mbedtls_ecjpake_context *ctx); |
| |
| #if defined(MBEDTLS_SELF_TEST) |
| |
| /** |
| * \brief Checkup routine |
| * |
| * \return 0 if successful, or 1 if a test failed |
| */ |
| int mbedtls_ecjpake_self_test(int verbose); |
| |
| #endif /* MBEDTLS_SELF_TEST */ |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| |
| #endif /* ecjpake.h */ |