mirror of
https://github.com/openssl/openssl.git
synced 2024-12-21 06:09:35 +08:00
63 lines
1.9 KiB
Plaintext
63 lines
1.9 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
PKCS5_PBKDF2_HMAC - password based derivation routine with salt and iteration count
|
|
|
|
=head1 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);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
PKCS5_PBKDF2_HMAC() derives a key from a password using a salt and iteration count
|
|
as specified in RFC 2898.
|
|
|
|
B<pass> is the password used in the derivation of length B<passlen>. B<pass>
|
|
is an optional parameter and can be NULL. If B<passlen> is -1, then the
|
|
function will calculate the length of B<pass> using strlen().
|
|
|
|
B<salt> is the salt used in the derivation of length B<saltlen>. If the
|
|
B<salt> is NULL, then B<saltlen> must be 0. The function will not
|
|
attempt to calculate the length of the B<salt> because its not assumed to
|
|
be NULL terminated.
|
|
|
|
B<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
|
|
B<iter> less than 1 is treated as a single iteration.
|
|
|
|
B<digest> is 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 B<out>. The size of the B<out> buffer
|
|
is specified via B<keylen>.
|
|
|
|
=head1 NOTES
|
|
|
|
A typical application of this function is to derive keying material for an
|
|
encryption algorithm from a password in the B<pass>, a salt in B<salt>,
|
|
and an iteration count.
|
|
|
|
Increasing the B<iter> parameter slows down the algorithm which makes it
|
|
harder for an attacker to peform a brute force attack using a large number
|
|
of candidate passwords.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
PKCS5_PBKDF2_HMAC() returns 1 on success or 0 on error.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<evp(3)|evp(3)>, L<rand(3)|rand(3)>,
|
|
L<EVP_BytesToKey(3)|EVP_BytesToKey(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
=cut
|