hash_hmac_file
Generating OATH-compliant OTP (one time passwords) results in PHP:
<?php
$otp = oath_truncate (oath_hotp ($key, $counter), $length);
function oath_hotp ($key, $counter) {
// Counter
$bin_counter = pack ('C*', $counter);
// Pad to 8 chars
if (strlen ($bin_counter) < 8) {
$bin_counter = str_repeat (chr(0), 8 - strlen ($bin_counter)) . $bin_counter;
}
// HMAC
$hash = hash_hmac ('sha1', $bin_counter, $key);
return $hash;
}
function oath_truncate ($hash, $length = 6) {
// The last byte is used as an offset
$offset = hexdec (substr ($hash, 38)) & 0xf;
// Extract the relevant part, and clear the first bit
$hex_truncated = substr ($hash, $offset * 2, 8);
$bin_truncated = decbin (hexdec ($hex_truncated));
$bin_truncated[0] = '0';
$dec_truncated = bindec ($bin_truncated);
return substr ($dec_truncated, 0 - $length);
}
?>
hash_hmac
(PHP 5 >= 5.1.2, PECL hash:1.1-1.5)
hash_hmac — Generate a keyed hash value using the HMAC method
Description
string hash_hmac
( string $algo
, string $data
, string $key
[, bool $raw_output
] )
Parameters
- algo
-
Name of selected hashing algorithm (i.e. "md5", "sha256", "haval160,4", etc..)
- data
-
Message to be hashed.
- key
-
Shared secret key used for generating the HMAC variant of the message digest.
- raw_output
-
When set to TRUE, outputs raw binary data. Default value (FALSE) outputs lowercase hexits.
Return Values
Returns a string containing the calculated message digest as lowercase hexits unless raw_output is set to true in which case the raw binary representation of the message digest is returned.
Examples
Example #1 hash_hmac() example
<?php
echo hash_hmac('ripemd160', 'The quick brown fox jumped over the lazy dog.', 'secret');
?>
The above example will output:
b8e7ae12510bdfb1812e463a7f086122cf37e4f7
add a note
User Contributed Noteshash_hmac
Carlos Averett(caverett*@*corecodec,net)
03-Jul-2008 11:54
03-Jul-2008 11:54