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 #if defined(__cplusplus) 21 extern "C" { 22 #endif 23 24 25 /* HKDF. */ 26 27 28 /* HKDF computes HKDF (as specified by RFC 5869) of initial keying material 29 * |secret| with |salt| and |info| using |digest|, and outputs |out_len| bytes 30 * to |out_key|. It returns one on success and zero on error. 31 * 32 * HKDF is an Extract-and-Expand algorithm. It does not do any key stretching, 33 * and as such, is not suited to be used alone to generate a key from a 34 * password. */ 35 OPENSSL_EXPORT int HKDF(uint8_t *out_key, size_t out_len, const EVP_MD *digest, 36 const uint8_t *secret, size_t secret_len, 37 const uint8_t *salt, size_t salt_len, 38 const uint8_t *info, size_t info_len); 39 40 /* HKDF_extract computes a HKDF PRK (as specified by RFC 5869) from initial 41 * keying material |secret| and salt |salt| using |digest|, and outputs 42 * |out_len| bytes to |out_key|. The maximum output size is |EVP_MAX_MD_SIZE|. 43 * It returns one on success and zero on error. */ 44 OPENSSL_EXPORT int HKDF_extract(uint8_t *out_key, size_t *out_len, 45 const EVP_MD *digest, const uint8_t *secret, 46 size_t secret_len, const uint8_t *salt, 47 size_t salt_len); 48 49 /* HKDF_expand computes a HKDF OKM (as specified by RFC 5869) of length 50 * |out_len| from the PRK |prk| and info |info| using |digest|, and outputs 51 * the result to |out_key|. It returns one on success and zero on error. */ 52 OPENSSL_EXPORT int HKDF_expand(uint8_t *out_key, size_t out_len, 53 const EVP_MD *digest, const uint8_t *prk, 54 size_t prk_len, const uint8_t *info, 55 size_t info_len); 56 57 58 #if defined(__cplusplus) 59 } /* extern C */ 60 #endif 61 62 #define HKDF_R_OUTPUT_TOO_LARGE 100 63 64 #endif /* OPENSSL_HEADER_HKDF_H */ 65
