library/cryptojs/components/pad-zeropadding.js


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/*
CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
/**
 * Zero padding strategy.
 */
CryptoJS.pad.ZeroPadding = {
    pad: function (data, blockSize) {
        // Shortcut
        var blockSizeBytes = blockSize * 4;

        // Pad
        data.clamp();
        data.sigBytes += blockSizeBytes - ((data.sigBytes % blockSizeBytes) || blockSizeBytes);
    },

    unpad: function (data) {
        // Shortcut
        var dataWords = data.words;

        // Unpad
        var i = data.sigBytes - 1;
        while (!((dataWords[i >>> 2] >>> (24 - (i % 4) * 8)) & 0xff)) {
            i--;
        }
        data.sigBytes = i + 1;
    }
};