1*72c33676SMaxim Ag /* $OpenBSD: hkdf.h,v 1.2 2018/04/03 13:33:53 tb Exp $ */ 2*72c33676SMaxim Ag /* Copyright (c) 2014, Google Inc. 3*72c33676SMaxim Ag * 4*72c33676SMaxim Ag * Permission to use, copy, modify, and/or distribute this software for any 5*72c33676SMaxim Ag * purpose with or without fee is hereby granted, provided that the above 6*72c33676SMaxim Ag * copyright notice and this permission notice appear in all copies. 7*72c33676SMaxim Ag * 8*72c33676SMaxim Ag * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9*72c33676SMaxim Ag * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10*72c33676SMaxim Ag * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 11*72c33676SMaxim Ag * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12*72c33676SMaxim Ag * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 13*72c33676SMaxim Ag * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 14*72c33676SMaxim Ag * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 15*72c33676SMaxim Ag 16*72c33676SMaxim Ag #ifndef OPENSSL_HEADER_HKDF_H 17*72c33676SMaxim Ag #define OPENSSL_HEADER_HKDF_H 18*72c33676SMaxim Ag 19*72c33676SMaxim Ag #include <openssl/evp.h> 20*72c33676SMaxim Ag 21*72c33676SMaxim Ag #if defined(__cplusplus) 22*72c33676SMaxim Ag extern "C" { 23*72c33676SMaxim Ag #endif 24*72c33676SMaxim Ag 25*72c33676SMaxim Ag /* 26*72c33676SMaxim Ag * HKDF computes HKDF (as specified by RFC 5869) of initial keying 27*72c33676SMaxim Ag * material |secret| with |salt| and |info| using |digest|, and 28*72c33676SMaxim Ag * outputs |out_len| bytes to |out_key|. It returns one on success and 29*72c33676SMaxim Ag * zero on error. 30*72c33676SMaxim Ag * 31*72c33676SMaxim Ag * HKDF is an Extract-and-Expand algorithm. It does not do any key 32*72c33676SMaxim Ag * stretching, and as such, is not suited to be used alone to generate 33*72c33676SMaxim Ag * a key from a password. 34*72c33676SMaxim Ag */ 35*72c33676SMaxim Ag 36*72c33676SMaxim Ag int HKDF(uint8_t *out_key, size_t out_len, const struct env_md_st *digest, 37*72c33676SMaxim Ag const uint8_t *secret, size_t secret_len, const uint8_t *salt, 38*72c33676SMaxim Ag size_t salt_len, const uint8_t *info, size_t info_len); 39*72c33676SMaxim Ag 40*72c33676SMaxim Ag /* 41*72c33676SMaxim Ag * HKDF_extract computes a HKDF PRK (as specified by RFC 5869) from 42*72c33676SMaxim Ag * initial keying material |secret| and salt |salt| using |digest|, 43*72c33676SMaxim Ag * and outputs |out_len| bytes to |out_key|. The maximum output size 44*72c33676SMaxim Ag * is |EVP_MAX_MD_SIZE|. It returns one on success and zero on error. 45*72c33676SMaxim Ag */ 46*72c33676SMaxim Ag int HKDF_extract(uint8_t *out_key, size_t *out_len, 47*72c33676SMaxim Ag const struct env_md_st *digest, const uint8_t *secret, 48*72c33676SMaxim Ag size_t secret_len, const uint8_t *salt, size_t salt_len); 49*72c33676SMaxim Ag 50*72c33676SMaxim Ag /* 51*72c33676SMaxim Ag * HKDF_expand computes a HKDF OKM (as specified by RFC 5869) of 52*72c33676SMaxim Ag * length |out_len| from the PRK |prk| and info |info| using |digest|, 53*72c33676SMaxim Ag * and outputs the result to |out_key|. It returns one on success and 54*72c33676SMaxim Ag * zero on error. 55*72c33676SMaxim Ag */ 56*72c33676SMaxim Ag int HKDF_expand(uint8_t *out_key, size_t out_len, 57*72c33676SMaxim Ag const EVP_MD *digest, const uint8_t *prk, size_t prk_len, 58*72c33676SMaxim Ag const uint8_t *info, size_t info_len); 59*72c33676SMaxim Ag 60*72c33676SMaxim Ag 61*72c33676SMaxim Ag #if defined(__cplusplus) 62*72c33676SMaxim Ag } /* extern C */ 63*72c33676SMaxim Ag #endif 64*72c33676SMaxim Ag 65*72c33676SMaxim Ag #endif /* OPENSSL_HEADER_HKDF_H */ 66