encryption algorithm from a password in the B<data> parameter.
Increasing the B<count> parameter slows down the algorithm which makes it
-harder for an attacker to peform a brute force attack using a large number
+harder for an attacker to perform a brute force attack using a large number
of candidate passwords.
If the total key and IV length is less than the digest length and
B<MD5> is used then the derivation algorithm is compatible with PKCS#5 v1.5
otherwise a non standard extension is used to derive the extra data.
-Newer applications should use more standard algorithms such as PBKDF2 as
-defined in PKCS#5v2.1 for key derivation.
+Newer applications should use a more modern algorithm such as PBKDF2 as
+defined in PKCS#5v2.1 and provided by PKCS5_PBKDF2_HMAC.
=head1 KEY DERIVATION ALGORITHM
The key and IV is derived by concatenating D_1, D_2, etc until
enough data is available for the key and IV. D_i is defined as:
- D_i = HASH^count(D_(i-1) || data || salt)
+ D_i = HASH^count(D_(i-1) || data || salt)
-where || denotes concatentaion, D_0 is empty, HASH is the digest
+where || denotes concatenation, D_0 is empty, HASH is the digest
algorithm in use, HASH^1(data) is simply HASH(data), HASH^2(data)
is HASH(HASH(data)) and so on.
=head1 RETURN VALUES
-EVP_BytesToKey() returns the size of the derived key in bytes, or 0 on error.
+If B<data> is NULL, then EVP_BytesToKey() returns the number of bytes
+needed to store the derived key.
+Otherwise, EVP_BytesToKey() returns the size of the derived key in bytes,
+or 0 on error.
=head1 SEE ALSO
-L<evp(3)|evp(3)>, L<rand(3)|rand(3)>,
-L<PKCS5_PBKDF2_HMAC(3)|PKCS5_PBKDF2_HMAC(3)>,
-L<EVP_EncryptInit(3)|EVP_EncryptInit(3)>
+L<evp(3)>, L<rand(3)>,
+L<PKCS5_PBKDF2_HMAC(3)>,
+L<EVP_EncryptInit(3)>
-=head1 HISTORY
+=head1 COPYRIGHT
+
+Copyright 2001-2016 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
+L<https://www.openssl.org/source/license.html>.
=cut