You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
142 lines
3.2 KiB
142 lines
3.2 KiB
'use strict';
|
|
|
|
var assert = require('minimalistic-assert');
|
|
|
|
function Cipher(options) {
|
|
this.options = options;
|
|
|
|
this.type = this.options.type;
|
|
this.blockSize = 8;
|
|
this._init();
|
|
|
|
this.buffer = new Array(this.blockSize);
|
|
this.bufferOff = 0;
|
|
}
|
|
module.exports = Cipher;
|
|
|
|
Cipher.prototype._init = function _init() {
|
|
// Might be overrided
|
|
};
|
|
|
|
Cipher.prototype.update = function update(data) {
|
|
if (data.length === 0)
|
|
return [];
|
|
|
|
if (this.type === 'decrypt')
|
|
return this._updateDecrypt(data);
|
|
else
|
|
return this._updateEncrypt(data);
|
|
};
|
|
|
|
Cipher.prototype._buffer = function _buffer(data, off) {
|
|
// Append data to buffer
|
|
var min = Math.min(this.buffer.length - this.bufferOff, data.length - off);
|
|
for (var i = 0; i < min; i++)
|
|
this.buffer[this.bufferOff + i] = data[off + i];
|
|
this.bufferOff += min;
|
|
|
|
// Shift next
|
|
return min;
|
|
};
|
|
|
|
Cipher.prototype._flushBuffer = function _flushBuffer(out, off) {
|
|
this._update(this.buffer, 0, out, off);
|
|
this.bufferOff = 0;
|
|
return this.blockSize;
|
|
};
|
|
|
|
Cipher.prototype._updateEncrypt = function _updateEncrypt(data) {
|
|
var inputOff = 0;
|
|
var outputOff = 0;
|
|
|
|
var count = ((this.bufferOff + data.length) / this.blockSize) | 0;
|
|
var out = new Array(count * this.blockSize);
|
|
|
|
if (this.bufferOff !== 0) {
|
|
inputOff += this._buffer(data, inputOff);
|
|
|
|
if (this.bufferOff === this.buffer.length)
|
|
outputOff += this._flushBuffer(out, outputOff);
|
|
}
|
|
|
|
// Write blocks
|
|
var max = data.length - ((data.length - inputOff) % this.blockSize);
|
|
for (; inputOff < max; inputOff += this.blockSize) {
|
|
this._update(data, inputOff, out, outputOff);
|
|
outputOff += this.blockSize;
|
|
}
|
|
|
|
// Queue rest
|
|
for (; inputOff < data.length; inputOff++, this.bufferOff++)
|
|
this.buffer[this.bufferOff] = data[inputOff];
|
|
|
|
return out;
|
|
};
|
|
|
|
Cipher.prototype._updateDecrypt = function _updateDecrypt(data) {
|
|
var inputOff = 0;
|
|
var outputOff = 0;
|
|
|
|
var count = Math.ceil((this.bufferOff + data.length) / this.blockSize) - 1;
|
|
var out = new Array(count * this.blockSize);
|
|
|
|
// TODO(indutny): optimize it, this is far from optimal
|
|
for (; count > 0; count--) {
|
|
inputOff += this._buffer(data, inputOff);
|
|
outputOff += this._flushBuffer(out, outputOff);
|
|
}
|
|
|
|
// Buffer rest of the input
|
|
inputOff += this._buffer(data, inputOff);
|
|
|
|
return out;
|
|
};
|
|
|
|
Cipher.prototype.final = function final(buffer) {
|
|
var first;
|
|
if (buffer)
|
|
first = this.update(buffer);
|
|
|
|
var last;
|
|
if (this.type === 'encrypt')
|
|
last = this._finalEncrypt();
|
|
else
|
|
last = this._finalDecrypt();
|
|
|
|
if (first)
|
|
return first.concat(last);
|
|
else
|
|
return last;
|
|
};
|
|
|
|
Cipher.prototype._pad = function _pad(buffer, off) {
|
|
if (off === 0)
|
|
return false;
|
|
|
|
while (off < buffer.length)
|
|
buffer[off++] = 0;
|
|
|
|
return true;
|
|
};
|
|
|
|
Cipher.prototype._finalEncrypt = function _finalEncrypt() {
|
|
if (!this._pad(this.buffer, this.bufferOff))
|
|
return [];
|
|
|
|
var out = new Array(this.blockSize);
|
|
this._update(this.buffer, 0, out, 0);
|
|
return out;
|
|
};
|
|
|
|
Cipher.prototype._unpad = function _unpad(buffer) {
|
|
return buffer;
|
|
};
|
|
|
|
Cipher.prototype._finalDecrypt = function _finalDecrypt() {
|
|
assert.equal(this.bufferOff, this.blockSize, 'Not enough data to decrypt');
|
|
var out = new Array(this.blockSize);
|
|
this._flushBuffer(out, 0);
|
|
|
|
return this._unpad(out);
|
|
};
|