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
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