filer/lib/crypto-js/components/pad-ansix923.js

36 lines
994 B
JavaScript

/*
CryptoJS v3.0.2
code.google.com/p/crypto-js
(c) 2009-2012 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
/**
* ANSI X.923 padding strategy.
*/
CryptoJS.pad.AnsiX923 = {
pad: function (data, blockSize) {
// Shortcuts
var dataSigBytes = data.sigBytes;
var blockSizeBytes = blockSize * 4;
// Count padding bytes
var nPaddingBytes = blockSizeBytes - dataSigBytes % blockSizeBytes;
// Compute last byte position
var lastBytePos = dataSigBytes + nPaddingBytes - 1;
// Pad
data.clamp();
data.words[lastBytePos >>> 2] |= nPaddingBytes << (24 - (lastBytePos % 4) * 8);
data.sigBytes += nPaddingBytes;
},
unpad: function (data) {
// Get number of padding bytes from last byte
var nPaddingBytes = data.words[(data.sigBytes - 1) >>> 2] & 0xff;
// Remove padding
data.sigBytes -= nPaddingBytes;
}
};