1 /* 2 * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved. 3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved. 4 * 5 * Licensed under the OpenSSL license (the "License"). You may not use 6 * this file except in compliance with the License. You can obtain a copy 7 * in the file LICENSE in the source distribution or at 8 * https://www.openssl.org/source/license.html 9 */ 10 11 #ifndef OPENSSL_HEADER_ECDH_H 12 #define OPENSSL_HEADER_ECDH_H 13 14 #include <openssl/base.h> 15 16 #include <openssl/ec_key.h> 17 18 #if defined(__cplusplus) 19 extern "C" { 20 #endif 21 22 23 // Elliptic curve Diffie-Hellman. 24 25 26 // ECDH_compute_key calculates the shared key between |pub_key| and |priv_key|. 27 // If |kdf| is not NULL, then it is called with the bytes of the shared key and 28 // the parameter |out|. When |kdf| returns, the value of |*outlen| becomes the 29 // return value. Otherwise, as many bytes of the shared key as will fit are 30 // copied directly to, at most, |outlen| bytes at |out|. It returns the number 31 // of bytes written to |out|, or -1 on error. 32 OPENSSL_EXPORT int ECDH_compute_key( 33 void *out, size_t outlen, const EC_POINT *pub_key, const EC_KEY *priv_key, 34 void *(*kdf)(const void *in, size_t inlen, void *out, size_t *outlen)); 35 36 // ECDH_compute_key_fips calculates the shared key between |pub_key| and 37 // |priv_key| and hashes it with the appropriate SHA function for |out_len|. The 38 // only value values for |out_len| are thus 24 (SHA-224), 32 (SHA-256), 48 39 // (SHA-384), and 64 (SHA-512). It returns one on success and zero on error. 40 // 41 // Note that the return value is different to |ECDH_compute_key|: it returns an 42 // error flag (as is common for BoringSSL) rather than the number of bytes 43 // written. 44 // 45 // This function allows the FIPS module to compute an ECDH and KDF within the 46 // module boundary without taking an arbitrary function pointer for the KDF, 47 // which isn't very FIPSy. 48 OPENSSL_EXPORT int ECDH_compute_key_fips(uint8_t *out, size_t out_len, 49 const EC_POINT *pub_key, 50 const EC_KEY *priv_key); 51 52 53 #if defined(__cplusplus) 54 } // extern C 55 #endif 56 57 #define ECDH_R_KDF_FAILED 100 58 #define ECDH_R_NO_PRIVATE_VALUE 101 59 #define ECDH_R_POINT_ARITHMETIC_FAILURE 102 60 #define ECDH_R_UNKNOWN_DIGEST_LENGTH 103 61 62 #endif // OPENSSL_HEADER_ECDH_H 63