/* Copyright (c) 2022, Google Inc. * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #ifndef OPENSSL_HEADER_KDF_H #define OPENSSL_HEADER_KDF_H #include <openssl/base.h> #if defined(__cplusplus) extern "C" { #endif // KDF support for EVP. // HKDF-specific functions. // // The following functions are provided for OpenSSL compatibility. Prefer the // HKDF functions in <openssl/hkdf.h>. In each, |ctx| must be created with // |EVP_PKEY_CTX_new_id| with |EVP_PKEY_HKDF| and then initialized with // |EVP_PKEY_derive_init|. // EVP_PKEY_HKDEF_MODE_* define "modes" for use with |EVP_PKEY_CTX_hkdf_mode|. // The mispelling of "HKDF" as "HKDEF" is intentional for OpenSSL compatibility. #define EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND … #define EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY … #define EVP_PKEY_HKDEF_MODE_EXPAND_ONLY … // EVP_PKEY_CTX_hkdf_mode configures which HKDF operation to run. It returns one // on success and zero on error. |mode| must be one of |EVP_PKEY_HKDEF_MODE_*|. // By default, the mode is |EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND|. // // If |mode| is |EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND| or // |EVP_PKEY_HKDEF_MODE_EXPAND_ONLY|, the output is variable-length. // |EVP_PKEY_derive| uses the size of the output buffer as the output length for // HKDF-Expand. // // WARNING: Although this API calls it a "mode", HKDF-Extract and HKDF-Expand // are distinct operations with distinct inputs and distinct kinds of keys. // Callers should not pass input secrets for one operation into the other. OPENSSL_EXPORT int EVP_PKEY_CTX_hkdf_mode(EVP_PKEY_CTX *ctx, int mode); // EVP_PKEY_CTX_set_hkdf_md sets |md| as the digest to use with HKDF. It returns // one on success and zero on error. OPENSSL_EXPORT int EVP_PKEY_CTX_set_hkdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); // EVP_PKEY_CTX_set1_hkdf_key configures HKDF to use |key_len| bytes from |key| // as the "key", described below. It returns one on success and zero on error. // // Which input is the key depends on the "mode" (see |EVP_PKEY_CTX_hkdf_mode|). // If |EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND| or // |EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY|, this function specifies the input keying // material (IKM) for HKDF-Extract. If |EVP_PKEY_HKDEF_MODE_EXPAND_ONLY|, it // instead specifies the pseudorandom key (PRK) for HKDF-Expand. OPENSSL_EXPORT int EVP_PKEY_CTX_set1_hkdf_key(EVP_PKEY_CTX *ctx, const uint8_t *key, size_t key_len); // EVP_PKEY_CTX_set1_hkdf_salt configures HKDF to use |salt_len| bytes from // |salt| as the salt parameter to HKDF-Extract. It returns one on success and // zero on error. If performing HKDF-Expand only, this parameter is ignored. OPENSSL_EXPORT int EVP_PKEY_CTX_set1_hkdf_salt(EVP_PKEY_CTX *ctx, const uint8_t *salt, size_t salt_len); // EVP_PKEY_CTX_add1_hkdf_info appends |info_len| bytes from |info| to the info // parameter used with HKDF-Expand. It returns one on success and zero on error. // If performing HKDF-Extract only, this parameter is ignored. OPENSSL_EXPORT int EVP_PKEY_CTX_add1_hkdf_info(EVP_PKEY_CTX *ctx, const uint8_t *info, size_t info_len); #if defined(__cplusplus) } // extern C #endif #endif // OPENSSL_HEADER_KDF_H