20865b4a6f
Deprecated in 1.31 and not used anywhere. Change-Id: Idc2e9cec907e39cacc391fdd7e2718bd880081ae
53 lines
2.2 KiB
PHP
53 lines
2.2 KiB
PHP
<?php
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/**
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* A cryptographic random generator class used for generating secret keys
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*
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* This is based in part on Drupal code as well as what we used in our own code
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* prior to introduction of this class.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @author Daniel Friesen
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* @file
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*/
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class MWCryptRand {
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/**
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* Generate a run of cryptographically random data and return
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* it in hexadecimal string format.
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*
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* @param int $chars The number of hex chars of random data to generate
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* @return string Hexadecimal random data
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*/
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public static function generateHex( $chars ) {
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// hex strings are 2x the length of raw binary so we divide the length in half
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// odd numbers will result in a .5 that leads the generate() being 1 character
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// short, so we use ceil() to ensure that we always have enough bytes
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$bytes = ceil( $chars / 2 );
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// Generate the data and then convert it to a hex string
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$hex = bin2hex( random_bytes( $bytes ) );
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// A bit of paranoia here, the caller asked for a specific length of string
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// here, and it's possible (eg when given an odd number) that we may actually
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// have at least 1 char more than they asked for. Just in case they made this
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// call intending to insert it into a database that does truncation we don't
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// want to give them too much and end up with their database and their live
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// code having two different values because part of what we gave them is truncated
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// hence, we strip out any run of characters longer than what we were asked for.
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return substr( $hex, 0, $chars );
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}
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}
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