1 /* Copyright (c) 2014, Google Inc. 2 * 3 * Permission to use, copy, modify, and/or distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 14 15 #ifndef OPENSSL_HEADER_HKDF_H 16 #define OPENSSL_HEADER_HKDF_H 17 18 #include <openssl/base.h> 19 20 #ifdef __cplusplus 21 extern "C" { 22 #endif 23 24 25 /* Computes HKDF (as specified by RFC 5869) of initial keying material |secret| 26 * with |salt| and |info| using |digest|, and outputs |out_len| bytes to 27 * |out_key|. It returns one on success and zero on error. 28 * 29 * HKDF is an Extract-and-Expand algorithm. It does not do any key stretching, 30 * and as such, is not suited to be used alone to generate a key from a 31 * password. */ 32 OPENSSL_EXPORT int HKDF(uint8_t *out_key, size_t out_len, const EVP_MD *digest, 33 const uint8_t *secret, size_t secret_len, 34 const uint8_t *salt, size_t salt_len, 35 const uint8_t *info, size_t info_len); 36 37 38 #if defined(__cplusplus) 39 } /* extern C */ 40 #endif 41 42 #define HKDF_R_OUTPUT_TOO_LARGE 100 43 44 #endif /* OPENSSL_HEADER_HKDF_H */ 45