| /** |
| * \file lmots.h |
| * |
| * \brief This file provides an API for the LM-OTS post-quantum-safe one-time |
| * public-key signature scheme as defined in RFC8554 and NIST.SP.200-208. |
| * This implementation currently only supports a single parameter set |
| * MBEDTLS_LMOTS_SHA256_N32_W8 in order to reduce complexity. |
| */ |
| /* |
| * 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_LMOTS_H |
| #define MBEDTLS_LMOTS_H |
| |
| #include "mbedtls/build_info.h" |
| |
| #include "psa/crypto.h" |
| |
| #include <stdint.h> |
| #include <stddef.h> |
| |
| /* Currently only defined for SHA256, 32 is the max hash output size */ |
| #define MBEDTLS_LMOTS_N_HASH_LEN_MAX (32u) |
| #define MBEDTLS_LMOTS_P_SIG_DIGIT_COUNT_MAX (34u) |
| #define MBEDTLS_LMOTS_N_HASH_LEN(type) (type == MBEDTLS_LMOTS_SHA256_N32_W8 ? 32u : 0) |
| #define MBEDTLS_LMOTS_P_SIG_DIGIT_COUNT(type) (type == MBEDTLS_LMOTS_SHA256_N32_W8 ? 34u : 0) |
| #define MBEDTLS_LMOTS_C_RANDOM_VALUE_LEN(type) (MBEDTLS_LMOTS_N_HASH_LEN(type)) |
| #define MBEDTLS_LMOTS_TYPE_LEN (4u) |
| #define MBEDTLS_LMOTS_I_KEY_ID_LEN (16u) |
| #define MBEDTLS_LMOTS_Q_LEAF_ID_LEN (4u) |
| |
| #define MBEDTLS_LMOTS_SIG_LEN(type) (MBEDTLS_LMOTS_TYPE_LEN + \ |
| MBEDTLS_LMOTS_C_RANDOM_VALUE_LEN(type) + \ |
| (MBEDTLS_LMOTS_P_SIG_DIGIT_COUNT(type) * \ |
| MBEDTLS_LMOTS_N_HASH_LEN(type))) |
| |
| #define MBEDTLS_LMOTS_PUBLIC_KEY_LEN(type) (MBEDTLS_LMOTS_TYPE_LEN + \ |
| MBEDTLS_LMOTS_I_KEY_ID_LEN + \ |
| MBEDTLS_LMOTS_Q_LEAF_ID_LEN + \ |
| MBEDTLS_LMOTS_N_HASH_LEN(type)) |
| |
| #define MBEDTLS_LMOTS_SIG_TYPE_OFFSET (0) |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** The Identifier of the LMS parameter set, as per |
| * https://www.iana.org/assignments/leighton-micali-signatures/leighton-micali-signatures.xhtml. |
| * We are only implementing a subset of the types, particularly N32_W8, for the sake of simplicty. |
| */ |
| typedef enum { |
| MBEDTLS_LMOTS_SHA256_N32_W8 = 4 |
| } mbedtls_lmots_algorithm_type_t; |
| |
| |
| /** LMOTS parameters structure. |
| * |
| * This contains the metadata associated with an LMOTS key, detailing the |
| * algorithm type, the key ID, and the leaf identifier should be key be part of |
| * a LMS key. |
| */ |
| typedef struct { |
| unsigned char MBEDTLS_PRIVATE(I_key_identifier[MBEDTLS_LMOTS_I_KEY_ID_LEN]); /*!< The key |
| identifier. */ |
| unsigned char MBEDTLS_PRIVATE(q_leaf_identifier[MBEDTLS_LMOTS_Q_LEAF_ID_LEN]); /*!< Which |
| leaf of the LMS key this is. |
| 0 if the key is not part of an LMS key. */ |
| mbedtls_lmots_algorithm_type_t MBEDTLS_PRIVATE(type); /*!< The LM-OTS key type identifier as |
| per IANA. Only SHA256_N32_W8 is |
| currently supported. */ |
| } mbedtls_lmots_parameters_t; |
| |
| /** LMOTS public context structure. |
| * |
| * A LMOTS public key is a hash output, and the applicable parameter set. |
| * |
| * The context must be initialized before it is used. A public key must either |
| * be imported or generated from a private context. |
| * |
| * \dot |
| * digraph lmots_public_t { |
| * UNINITIALIZED -> INIT [label="init"]; |
| * HAVE_PUBLIC_KEY -> INIT [label="free"]; |
| * INIT -> HAVE_PUBLIC_KEY [label="import_public_key"]; |
| * INIT -> HAVE_PUBLIC_KEY [label="calculate_public_key from private key"]; |
| * HAVE_PUBLIC_KEY -> HAVE_PUBLIC_KEY [label="export_public_key"]; |
| * } |
| * \enddot |
| */ |
| typedef struct { |
| mbedtls_lmots_parameters_t MBEDTLS_PRIVATE(params); |
| unsigned char MBEDTLS_PRIVATE(public_key)[32]; |
| unsigned char MBEDTLS_PRIVATE(have_public_key); /*!< Whether the context contains a public key. |
| Boolean values only. */ |
| } mbedtls_lmots_public_t; |
| |
| #ifdef MBEDTLS_LMS_PRIVATE |
| /** LMOTS private context structure. |
| * |
| * A LMOTS private key is one hash output for each of digit of the digest + |
| * checksum, and the applicable parameter set. |
| * |
| * The context must be initialized before it is used. A public key must either |
| * be imported or generated from a private context. |
| * |
| * \dot |
| * digraph lmots_public_t { |
| * UNINITIALIZED -> INIT [label="init"]; |
| * HAVE_PRIVATE_KEY -> INIT [label="free"]; |
| * INIT -> HAVE_PRIVATE_KEY [label="generate_private_key"]; |
| * HAVE_PRIVATE_KEY -> INIT [label="sign"]; |
| * } |
| * \enddot |
| */ |
| typedef struct { |
| mbedtls_lmots_parameters_t MBEDTLS_PRIVATE(params); |
| unsigned char MBEDTLS_PRIVATE(private_key)[MBEDTLS_LMOTS_P_SIG_DIGIT_COUNT_MAX][32]; |
| unsigned char MBEDTLS_PRIVATE(have_private_key); /*!< Whether the context contains a private key. |
| Boolean values only. */ |
| } mbedtls_lmots_private_t; |
| #endif /* MBEDTLS_LMS_PRIVATE */ |
| |
| /** |
| * \brief This function converts an unsigned int into a |
| * network-byte-order (big endian) string. |
| * |
| * \param val The unsigned integer value |
| * \param len The length of the string. |
| * \param bytes The string to output into. |
| * |
| * \return The corresponding LMS error code. |
| */ |
| void unsigned_int_to_network_bytes(unsigned int val, size_t len, |
| unsigned char *bytes); |
| |
| /** |
| * \brief This function converts a network-byte-order |
| * (big endian) string into an unsigned integer. |
| * |
| * \param len The length of the string. |
| * \param bytes The string. |
| * |
| * \return The corresponding LMS error code. |
| */ |
| unsigned int network_bytes_to_unsigned_int(size_t len, |
| const unsigned char *bytes); |
| |
| /** |
| * \brief This function converts a \ref psa_status_t to a |
| * low-level LMS error code. |
| * |
| * \param status The psa_status_t to convert |
| * |
| * \return The corresponding LMS error code. |
| */ |
| int mbedtls_lms_error_from_psa(psa_status_t status); |
| |
| |
| /** |
| * \brief This function initializes a public LMOTS context |
| * |
| * \param ctx The uninitialized LMOTS context that will then be |
| * initialized. |
| */ |
| void mbedtls_lmots_init_public( mbedtls_lmots_public_t *ctx ); |
| |
| /** |
| * \brief This function uninitializes a public LMOTS context |
| * |
| * \param ctx The initialized LMOTS context that will then be |
| * uninitialized. |
| */ |
| void mbedtls_lmots_free_public( mbedtls_lmots_public_t *ctx ); |
| |
| /** |
| * \brief This function imports an LMOTS public key into a |
| * LMOTS context. |
| * |
| * \note Before this function is called, the context must |
| * have been initialized. |
| * |
| * \note See IETF RFC8554 for details of the encoding of |
| * this public key. |
| * |
| * \param ctx The initialized LMOTS context store the key in. |
| * \param key The buffer from which the key will be read. |
| * #MBEDTLS_LMOTS_PUBLIC_KEY_LEN bytes will be read |
| * from this. |
| * |
| * \return \c 0 on success. |
| * \return A non-zero error code on failure. |
| */ |
| int mbedtls_lmots_import_public_key( mbedtls_lmots_public_t *ctx, |
| const unsigned char *key, size_t key_size ); |
| |
| /** |
| * \brief This function creates a candidate public key from |
| * an LMOTS signature. This can then be compared to |
| * the real public key to determine the validity of |
| * the signature. |
| * |
| * \note This function is exposed publicly to be used in LMS |
| * signature verification, it is expected that |
| * mbedtls_lmots_verify will be used for LMOTS |
| * signature verification. |
| * |
| * \param params The LMOTS parameter set, q and I values as an |
| * mbedtls_lmots_parameters_t struct. |
| * \param msg The buffer from which the message will be read. |
| * \param msg_size The size of the message that will be read. |
| * \param sig The buffer from which the signature will be read. |
| * #MBEDTLS_LMOTS_SIG_LEN bytes will be read from |
| * this. |
| * \param out The buffer where the candidate public key will be |
| * stored. Must be at least #MBEDTLS_LMOTS_N_HASH_LEN |
| * bytes in size. |
| * |
| * \return \c 0 on success. |
| * \return A non-zero error code on failure. |
| */ |
| int mbedtls_lmots_calculate_public_key_candidate( const mbedtls_lmots_parameters_t *params, |
| const unsigned char *msg, |
| size_t msg_size, |
| const unsigned char *sig, |
| size_t sig_size, |
| unsigned char *out, |
| size_t out_size, |
| size_t *out_len); |
| |
| /** |
| * \brief This function verifies a LMOTS signature, using a |
| * LMOTS context that contains a public key. |
| * |
| * \warning This function is **not intended for use in |
| * production**, due to as-yet unsolved problems with |
| * handling stateful keys. |
| * |
| * \note Before this function is called, the context must |
| * have been initialized and must contain a public key |
| * (either by import or calculation from a private |
| * key). |
| * |
| * \param ctx The initialized LMOTS context from which the public |
| * key will be read. |
| * \param msg The buffer from which the message will be read. |
| * \param msg_size The size of the message that will be read. |
| * \param sig The buf from which the signature will be read. |
| * #MBEDTLS_LMOTS_SIG_LEN bytes will be read from |
| * this. |
| * |
| * \return \c 0 on successful verification. |
| * \return A non-zero error code on failure. |
| */ |
| int mbedtls_lmots_verify( mbedtls_lmots_public_t *ctx, const unsigned char *msg, |
| size_t msg_size, const unsigned char *sig, |
| size_t sig_size ); |
| |
| #ifdef MBEDTLS_LMS_PRIVATE |
| |
| /** |
| * \brief This function initializes a private LMOTS context |
| * |
| * \param ctx The uninitialized LMOTS context that will then be |
| * initialized. |
| */ |
| void mbedtls_lmots_init_private( mbedtls_lmots_private_t *ctx ); |
| |
| /** |
| * \brief This function uninitializes a private LMOTS context |
| * |
| * \param ctx The initialized LMOTS context that will then be |
| * uninitialized. |
| */ |
| void mbedtls_lmots_free_private( mbedtls_lmots_private_t *ctx ); |
| |
| /** |
| * \brief This function generates an LMOTS private key, and |
| * stores in into an LMOTS context. |
| * |
| * \warning This function is **not intended for use in |
| * production**, due to as-yet unsolved problems with |
| * handling stateful keys. |
| * |
| * \note The seed must have at least 256 bits of entropy. |
| * |
| * \param ctx The initialized LMOTS context to generate the key |
| * into. |
| * \param I_key_identifier The key identifier of the key, as a 16-byte string. |
| * \param q_leaf_identifier The leaf identifier of key. If this LMOTS key is |
| * not being used as part of an LMS key, this should |
| * be set to 0. |
| * \param seed The seed used to deterministically generate the |
| * key. |
| * \param seed_size The length of the seed. |
| * |
| * \return \c 0 on success. |
| * \return A non-zero error code on failure. |
| */ |
| int mbedtls_lmots_generate_private_key( mbedtls_lmots_private_t *ctx, |
| mbedtls_lmots_algorithm_type_t type, |
| const unsigned char I_key_identifier[MBEDTLS_LMOTS_I_KEY_ID_LEN], |
| uint32_t q_leaf_identifier, |
| const unsigned char *seed, |
| size_t seed_size ); |
| |
| /** |
| * \brief This function generates an LMOTS public key from a |
| * LMOTS context that already contains a private key. |
| * |
| * \note Before this function is called, the context must |
| * have been initialized and the context must contain |
| * a private key. |
| * |
| * \param ctx The initialized LMOTS context to generate the key |
| * from and store it into. |
| * |
| * \return \c 0 on success. |
| * \return A non-zero error code on failure. |
| */ |
| int mbedtls_lmots_calculate_public_key( mbedtls_lmots_public_t *ctx, |
| mbedtls_lmots_private_t *priv_ctx); |
| |
| |
| /** |
| * \brief This function exports an LMOTS public key from a |
| * LMOTS context that already contains a public key. |
| * |
| * \note Before this function is called, the context must |
| * have been initialized and the context must contain |
| * a public key. |
| * |
| * \note See IETF RFC8554 for details of the encoding of |
| * this public key. |
| * |
| * \param ctx The initialized LMOTS context that contains the |
| * publc key. |
| * \param key The buffer into which the key will be output. Must |
| * be at least #MBEDTLS_LMOTS_PUBLIC_KEY_LEN in size. |
| * |
| * \return \c 0 on success. |
| * \return A non-zero error code on failure. |
| */ |
| int mbedtls_lmots_export_public_key( mbedtls_lmots_public_t *ctx, |
| unsigned char *key, size_t key_size, |
| size_t *key_len ); |
| /** |
| * \brief This function creates a LMOTS signature, using a |
| * LMOTS context that contains a private key. |
| * |
| * \note Before this function is called, the context must |
| * have been initialized and must contain a private |
| * key. |
| * |
| * \note LMOTS private keys can only be used once, otherwise |
| * attackers may be able to create forged signatures. |
| * If the signing operation is successful, the private |
| * key in the context will be erased, and no further |
| * signing will be possible until another private key |
| * is loaded |
| * |
| * \param ctx The initialized LMOTS context from which the |
| * private key will be read. |
| * \param f_rng The RNG function to be used for signature |
| * generation. |
| * \param p_rng The RNG context to be passed to f_rng |
| * \param msg The buffer from which the message will be read. |
| * \param msg_size The size of the message that will be read. |
| * \param sig The buf into which the signature will be stored. |
| * Must be at least #MBEDTLS_LMOTS_SIG_LEN in size. |
| * |
| * \return \c 0 on success. |
| * \return A non-zero error code on failure. |
| */ |
| int mbedtls_lmots_sign( mbedtls_lmots_private_t *ctx, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng, const unsigned char *msg, size_t msg_size, |
| unsigned char *sig, size_t sig_size, size_t* sig_len ); |
| |
| #endif /* MBEDTLS_LMS_PRIVATE */ |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* MBEDTLS_LMOTS_H */ |