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PKCS5_PBKDF2_HMAC(3) OpenSSL PKCS5_PBKDF2_HMAC(3)NAMEPKCS5_PBKDF2_HMAC, PKCS5_PBKDF2_HMAC_SHA1 - password based derivation routines with salt and iteration countLIBRARYlibcrypto, -lcryptoSYNOPSIS#include <openssl/evp.h> int PKCS5_PBKDF2_HMAC(const char *pass, int passlen, const unsigned char *salt, int saltlen, int iter, const EVP_MD *digest, int keylen, unsigned char *out); int PKCS5_PBKDF2_HMAC_SHA1(const char *pass, int passlen, const unsigned char *salt, int saltlen, int iter, int keylen, unsigned char *out);DESCRIPTIONPKCS5_PBKDF2_HMAC()derives a key from a password using a salt and iteration count as specified in RFC 2898.passis the password used in the derivation of lengthpasslen.passis an optional parameter and can be NULL. Ifpasslenis -1, then the function will calculate the length ofpassusingstrlen().saltis the salt used in the derivation of lengthsaltlen. If thesaltis NULL, thensaltlenmust be 0. The function will not attempt to calculate the length of thesaltbecause it is not assumed to be NULL terminated.iteris the iteration count and its value should be greater than or equal to 1. RFC 2898 suggests an iteration count of at least 1000. Anyiterless than 1 is treated as a single iteration.digestis the message digest function used in the derivation. Values include any of the EVP_* message digests.PKCS5_PBKDF2_HMAC_SHA1()callsPKCS5_PBKDF2_HMAC()withEVP_sha1(). The derived key will be written toout. The size of theoutbuffer is specified viakeylen.NOTESA typical application of this function is to derive keying material for an encryption algorithm from a password in thepass, a salt insalt, and an iteration count. Increasing theiterparameter slows down the algorithm which makes it harder for an attacker to perform a brute force attack using a large number of candidate passwords. These functions make no assumption regarding the given password. It will simply be treated as a byte sequence.RETURNVALUESPKCS5_PBKDF2_HMAC()andPBKCS5_PBKDF2_HMAC_SHA1()return 1 on success or 0 on error.SEE ALSOevp(7),RAND_bytes(3),EVP_BytesToKey(3),passphrase-encoding(7)COPYRIGHTCopyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>. 1.1.1i 2018-09-23 PKCS5_PBKDF2_HMAC(3)