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PKCS5_PBKDF2_HMAC(3)		    OpenSSL		  PKCS5_PBKDF2_HMAC(3)

NAME
       PKCS5_PBKDF2_HMAC, PKCS5_PBKDF2_HMAC_SHA1 - password based derivation
       routines	with salt and iteration	count

SYNOPSIS
	#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);

DESCRIPTION
       PKCS5_PBKDF2_HMAC() derives a key from a	password using a salt and
       iteration count as specified in RFC 2898.

       pass is the password used in the	derivation of length passlen. pass is
       an optional parameter and can be	NULL. If passlen is -1,	then the
       function	will calculate the length of pass using	strlen().

       salt is the salt	used in	the derivation of length saltlen. If the salt
       is NULL,	then saltlen must be 0.	The function will not attempt to
       calculate the length of the salt	because	it is not assumed to be	NULL
       terminated.

       iter is the iteration count and its value should	be greater than	or
       equal to	1. RFC 2898 suggests an	iteration count	of at least 1000. Any
       iter less than 1	is treated as a	single iteration.

       digest is the message digest function used in the derivation. Values
       include any of the EVP_*	message	digests. PKCS5_PBKDF2_HMAC_SHA1()
       calls PKCS5_PBKDF2_HMAC() with EVP_sha1().

       The derived key will be written to out. The size	of the out buffer is
       specified via keylen.

NOTES
       A typical application of	this function is to derive keying material for
       an encryption algorithm from a password in the pass, a salt in salt,
       and an iteration	count.

       Increasing the iter parameter 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.

RETURN VALUES
       PKCS5_PBKDF2_HMAC() and PBKCS5_PBKDF2_HMAC_SHA1() return	1 on success
       or 0 on error.

SEE ALSO
       evp(7), RAND_bytes(3), EVP_BytesToKey(3), passphrase-encoding(7)

COPYRIGHT
       Copyright 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>.

1.1.1d				  2019-09-10		  PKCS5_PBKDF2_HMAC(3)

NAME | SYNOPSIS | DESCRIPTION | NOTES | RETURN VALUES | SEE ALSO | COPYRIGHT

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