1*aa42de47Stb /* $OpenBSD: hkdf.h,v 1.3 2023/08/11 04:52:08 tb Exp $ */ 21eb0ad50Sbeck /* Copyright (c) 2014, Google Inc. 31eb0ad50Sbeck * 41eb0ad50Sbeck * Permission to use, copy, modify, and/or distribute this software for any 51eb0ad50Sbeck * purpose with or without fee is hereby granted, provided that the above 61eb0ad50Sbeck * copyright notice and this permission notice appear in all copies. 71eb0ad50Sbeck * 81eb0ad50Sbeck * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 91eb0ad50Sbeck * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 101eb0ad50Sbeck * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 111eb0ad50Sbeck * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 121eb0ad50Sbeck * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 131eb0ad50Sbeck * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 141eb0ad50Sbeck * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 151eb0ad50Sbeck 161eb0ad50Sbeck #ifndef OPENSSL_HEADER_HKDF_H 171eb0ad50Sbeck #define OPENSSL_HEADER_HKDF_H 181eb0ad50Sbeck 191eb0ad50Sbeck #include <openssl/evp.h> 201eb0ad50Sbeck 211eb0ad50Sbeck #if defined(__cplusplus) 221eb0ad50Sbeck extern "C" { 231eb0ad50Sbeck #endif 241eb0ad50Sbeck 251eb0ad50Sbeck /* 261eb0ad50Sbeck * HKDF computes HKDF (as specified by RFC 5869) of initial keying 271eb0ad50Sbeck * material |secret| with |salt| and |info| using |digest|, and 281eb0ad50Sbeck * outputs |out_len| bytes to |out_key|. It returns one on success and 291eb0ad50Sbeck * zero on error. 301eb0ad50Sbeck * 311eb0ad50Sbeck * HKDF is an Extract-and-Expand algorithm. It does not do any key 321eb0ad50Sbeck * stretching, and as such, is not suited to be used alone to generate 331eb0ad50Sbeck * a key from a password. 341eb0ad50Sbeck */ 351eb0ad50Sbeck 36*aa42de47Stb int HKDF(uint8_t *out_key, size_t out_len, const EVP_MD *digest, 371eb0ad50Sbeck const uint8_t *secret, size_t secret_len, const uint8_t *salt, 381eb0ad50Sbeck size_t salt_len, const uint8_t *info, size_t info_len); 391eb0ad50Sbeck 401eb0ad50Sbeck /* 411eb0ad50Sbeck * HKDF_extract computes a HKDF PRK (as specified by RFC 5869) from 421eb0ad50Sbeck * initial keying material |secret| and salt |salt| using |digest|, 431eb0ad50Sbeck * and outputs |out_len| bytes to |out_key|. The maximum output size 441eb0ad50Sbeck * is |EVP_MAX_MD_SIZE|. It returns one on success and zero on error. 451eb0ad50Sbeck */ 46*aa42de47Stb int HKDF_extract(uint8_t *out_key, size_t *out_len, const EVP_MD *digest, 47*aa42de47Stb const uint8_t *secret, size_t secret_len, 48*aa42de47Stb const uint8_t *salt, size_t salt_len); 491eb0ad50Sbeck 501eb0ad50Sbeck /* 511eb0ad50Sbeck * HKDF_expand computes a HKDF OKM (as specified by RFC 5869) of 521eb0ad50Sbeck * length |out_len| from the PRK |prk| and info |info| using |digest|, 531eb0ad50Sbeck * and outputs the result to |out_key|. It returns one on success and 541eb0ad50Sbeck * zero on error. 551eb0ad50Sbeck */ 561eb0ad50Sbeck int HKDF_expand(uint8_t *out_key, size_t out_len, 571eb0ad50Sbeck const EVP_MD *digest, const uint8_t *prk, size_t prk_len, 581eb0ad50Sbeck const uint8_t *info, size_t info_len); 591eb0ad50Sbeck 601eb0ad50Sbeck 611eb0ad50Sbeck #if defined(__cplusplus) 621eb0ad50Sbeck } /* extern C */ 631eb0ad50Sbeck #endif 641eb0ad50Sbeck 651eb0ad50Sbeck #endif /* OPENSSL_HEADER_HKDF_H */ 66