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Diffstat (limited to 'include/mbedtls/ecjpake.h')
| -rw-r--r-- | include/mbedtls/ecjpake.h | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/include/mbedtls/ecjpake.h b/include/mbedtls/ecjpake.h new file mode 100644 index 0000000..c2148a2 --- /dev/null +++ b/include/mbedtls/ecjpake.h @@ -0,0 +1,298 @@ +/** + * \file ecjpake.h + * + * \brief Elliptic curve J-PAKE + */ +/* + * Copyright The Mbed TLS Contributors + * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later + */ +#ifndef MBEDTLS_ECJPAKE_H +#define MBEDTLS_ECJPAKE_H +#include "mbedtls/private_access.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. + */ +#include "mbedtls/build_info.h" + +#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_NONE, /**< Undefined */ +} 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 { + mbedtls_md_type_t MBEDTLS_PRIVATE(md_type); /**< Hash to use */ + mbedtls_ecp_group MBEDTLS_PRIVATE(grp); /**< Elliptic curve */ + mbedtls_ecjpake_role MBEDTLS_PRIVATE(role); /**< Are we client or server? */ + int MBEDTLS_PRIVATE(point_format); /**< Format for point export */ + + mbedtls_ecp_point MBEDTLS_PRIVATE(Xm1); /**< My public key 1 C: X1, S: X3 */ + mbedtls_ecp_point MBEDTLS_PRIVATE(Xm2); /**< My public key 2 C: X2, S: X4 */ + mbedtls_ecp_point MBEDTLS_PRIVATE(Xp1); /**< Peer public key 1 C: X3, S: X1 */ + mbedtls_ecp_point MBEDTLS_PRIVATE(Xp2); /**< Peer public key 2 C: X4, S: X2 */ + mbedtls_ecp_point MBEDTLS_PRIVATE(Xp); /**< Peer public key C: Xs, S: Xc */ + + mbedtls_mpi MBEDTLS_PRIVATE(xm1); /**< My private key 1 C: x1, S: x3 */ + mbedtls_mpi MBEDTLS_PRIVATE(xm2); /**< My private key 2 C: x2, S: x4 */ + + mbedtls_mpi MBEDTLS_PRIVATE(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 not empty 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 Set the point format for future reads and writes. + * + * \param ctx The ECJPAKE context to configure. + * \param point_format The point format to use: + * #MBEDTLS_ECP_PF_UNCOMPRESSED (default) + * or #MBEDTLS_ECP_PF_COMPRESSED. + * + * \return \c 0 if successful. + * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if \p point_format + * is invalid. + */ +int mbedtls_ecjpake_set_point_format(mbedtls_ecjpake_context *ctx, + int point_format); + +/** + * \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 Write the shared key material to be passed to a Key + * Derivation Function as described in RFC8236. + * + * \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_write_shared_key(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 */ |