PKCS5_PBKDF2_HMAC, PKCS5_PBKDF2_HMAC_SHA1 - password based derivation routines
with salt and iteration count
#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);
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
value less than 1 is invalid; such values will result in failure and raise the
PROV_R_INVALID_ITERATION_COUNT error.
digest is the message digest function used in the derivation.
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.
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.
PKCS5_PBKDF2_HMAC() and
PBKCS5_PBKDF2_HMAC_SHA1() return 1 on
success or 0 on error.
evp(7),
RAND_bytes(3),
EVP_BytesToKey(3),
passphrase-encoding(7)
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Licensed under the Apache License 2.0 (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>.