PKCS5_PBKDF2_HMAC(3) LibreSSL 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);
DESCRIPTIONPKCS5_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 peform a brute force attack using a large
number of candidate passwords.
RETURN VALUESPKCS5_PBKDF2_HMAC() and PBKCS5_PBKDF2_HMAC_SHA1() return 1 on success
or 0 on error.
SEE ALSOevp(3), rand(3), EVP_BytesToKey(3)LibreSSL 2015-12-05 PKCS5_PBKDF2_HMAC(3)
