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Diffstat (limited to 'src/lib/crypto/ecdh.h')
| -rw-r--r-- | src/lib/crypto/ecdh.h | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/src/lib/crypto/ecdh.h b/src/lib/crypto/ecdh.h new file mode 100644 index 0000000..017e1e6 --- /dev/null +++ b/src/lib/crypto/ecdh.h @@ -0,0 +1,117 @@ +/*- + * Copyright (c) 2017 Ribose Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef ECDH_H_ +#define ECDH_H_ + +#include "crypto/ec.h" + +/* Max size of wrapped and obfuscated key size + * + * RNP pads a key with PKCS-5 always to 8 byte granularity, + * then 8 bytes is added by AES-wrap (RFC3394). + */ +#define ECDH_WRAPPED_KEY_SIZE 48 + +/* Forward declarations */ +typedef struct pgp_fingerprint_t pgp_fingerprint_t; + +typedef struct pgp_ecdh_encrypted_t { + pgp_mpi_t p; + uint8_t m[ECDH_WRAPPED_KEY_SIZE]; + size_t mlen; +} pgp_ecdh_encrypted_t; + +rnp_result_t ecdh_validate_key(rnp::RNG *rng, const pgp_ec_key_t *key, bool secret); + +/* + * @brief Sets hash algorithm and key wrapping algo + * based on curve_id + * + * @param key ec key to set parameters for + * @param curve underlying ECC curve ID + * + * @returns false if curve is not supported, otherwise true + */ +bool ecdh_set_params(pgp_ec_key_t *key, pgp_curve_t curve_id); + +/* + * Encrypts session key with a KEK agreed during ECDH as specified in + * RFC 4880 bis 01, 13.5 + * + * @param rng initialized rnp::RNG object + * @param session_key key to be encrypted + * @param session_key_len length of the key buffer + * @param wrapped_key [out] resulting key wrapped in by some AES + * as specified in RFC 3394 + * @param wrapped_key_len [out] length of the `wrapped_key' buffer + * Current implementation always produces 48 bytes as key + * is padded with PKCS-5/7 + * @param ephemeral_key [out] public ephemeral ECDH key used for key + * agreement (private part). Must be initialized + * @param pubkey public key to be used for encryption + * @param fingerprint fingerprint of the pubkey + * + * @return RNP_SUCCESS on success and output parameters are populated + * @return RNP_ERROR_NOT_SUPPORTED unknown curve + * @return RNP_ERROR_BAD_PARAMETERS unexpected input provided + * @return RNP_ERROR_SHORT_BUFFER `wrapped_key_len' to small to store result + * @return RNP_ERROR_GENERIC implementation error + */ +rnp_result_t ecdh_encrypt_pkcs5(rnp::RNG * rng, + pgp_ecdh_encrypted_t * out, + const uint8_t *const in, + size_t in_len, + const pgp_ec_key_t * key, + const pgp_fingerprint_t &fingerprint); + +/* + * Decrypts session key with a KEK agreed during ECDH as specified in + * RFC 4880 bis 01, 13.5 + * + * @param session_key [out] resulting session key + * @param session_key_len [out] length of the resulting session key + * @param wrapped_key session key wrapped with some AES as specified + * in RFC 3394 + * @param wrapped_key_len length of the `wrapped_key' buffer + * @param ephemeral_key public ephemeral ECDH key coming from + * encrypted packet. + * @param seckey secret key to be used for decryption + * @param fingerprint fingerprint of the key + * + * @return RNP_SUCCESS on success and output parameters are populated + * @return RNP_ERROR_NOT_SUPPORTED unknown curve + * @return RNP_ERROR_BAD_PARAMETERS unexpected input provided + * @return RNP_ERROR_SHORT_BUFFER `session_key_len' to small to store result + * @return RNP_ERROR_GENERIC decryption failed or implementation error + */ +rnp_result_t ecdh_decrypt_pkcs5(uint8_t * out, + size_t * out_len, + const pgp_ecdh_encrypted_t *in, + const pgp_ec_key_t * key, + const pgp_fingerprint_t & fingerprint); + +#endif // ECDH_H_ |