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'use strict';
var assert = require('minimalistic-assert');
var inherits = require('inherits');
var Cipher = require('./cipher');
var DES = require('./des');
function EDEState(type, key) {
assert.equal(key.length, 24, 'Invalid key length');
var k1 = key.slice(0, 8);
var k2 = key.slice(8, 16);
var k3 = key.slice(16, 24);
if (type === 'encrypt') {
this.ciphers = [
DES.create({ type: 'encrypt', key: k1 }),
DES.create({ type: 'decrypt', key: k2 }),
DES.create({ type: 'encrypt', key: k3 })
];
} else {
this.ciphers = [
DES.create({ type: 'decrypt', key: k3 }),
DES.create({ type: 'encrypt', key: k2 }),
DES.create({ type: 'decrypt', key: k1 })
];
}
}
function EDE(options) {
Cipher.call(this, options);
var state = new EDEState(this.type, this.options.key);
this._edeState = state;
}
inherits(EDE, Cipher);
module.exports = EDE;
EDE.create = function create(options) {
return new EDE(options);
};
EDE.prototype._update = function _update(inp, inOff, out, outOff) {
var state = this._edeState;
state.ciphers[0]._update(inp, inOff, out, outOff);
state.ciphers[1]._update(out, outOff, out, outOff);
state.ciphers[2]._update(out, outOff, out, outOff);
};
EDE.prototype._pad = DES.prototype._pad;
EDE.prototype._unpad = DES.prototype._unpad;