115 lines
3.4 KiB
JavaScript
115 lines
3.4 KiB
JavaScript
define(function(require) {
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// AES encryption, see http://code.google.com/p/crypto-js/#AES
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require("crypto-js/rollups/aes");
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// DES, Triple DES, see http://code.google.com/p/crypto-js/#DES,_Triple_DES
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require("crypto-js/rollups/tripledes");
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// Rabbit, see http://code.google.com/p/crypto-js/#Rabbit
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require("crypto-js/rollups/rabbit");
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function CryptoContext(context, encrypt, decrypt) {
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this.context = context;
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this.encrypt = encrypt;
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this.decrypt = decrypt;
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}
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CryptoContext.prototype.clear = function(callback) {
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this.context.clear(callback);
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};
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CryptoContext.prototype.get = function(key, callback) {
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var decrypt = this.decrypt;
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this.context.get(key, function(err, value) {
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if(err) {
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callback(err);
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return;
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}
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if(value) {
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value = decrypt(value);
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}
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callback(null, value);
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});
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};
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CryptoContext.prototype.put = function(key, value, callback) {
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var encryptedValue = this.encrypt(value);
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this.context.put(key, encryptedValue, callback);
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};
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CryptoContext.prototype.delete = function(key, callback) {
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this.context.delete(key, callback);
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};
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// Move back and forth from Uint8Arrays and CryptoJS' WordArray
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// source: https://groups.google.com/forum/#!topic/crypto-js/TOb92tcJlU0
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Uint8ArrayFormatter = {
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stringify: function (wordArray) {
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// Shortcuts
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var words = wordArray.words;
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var sigBytes = wordArray.sigBytes;
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// Convert
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var u8 = new Uint8Array(sigBytes);
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for (var i = 0; i < sigBytes; i++) {
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var byte = (words[i >>> 2] >>> (24 - (i % 4) * 8)) & 0xff;
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u8[i]=byte;
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}
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return u8;
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},
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parse: function (u8arr) {
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// Shortcut
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var len = u8arr.length;
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// Convert
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var words = [];
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for (var i = 0; i < len; i++) {
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words[i >>> 2] |= (u8arr[i] & 0xff) << (24 - (i % 4) * 8);
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}
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return CryptoJS.lib.WordArray.create(words, len);
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}
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};
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function buildCryptoAdapter(encryptionType) {
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// It is up to the app using this wrapper how the passphrase is acquired, probably by
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// prompting the user to enter it when the file system is being opened.
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function CryptoAdapter(passphrase, provider) {
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this.provider = provider;
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this.encrypt = function(plain) {
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return CryptoJS[encryptionType]
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.encrypt(plain, passphrase, {format: Uint8ArrayFormatter})
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.toString();
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};
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this.decrypt = function(encrypted) {
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return CryptoJS[encryptionType]
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.decrypt(encrypted, passphrase, {format: Uint8ArrayFormatter})
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.toString(); //CryptoJS.enc.Utf8);
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};
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}
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CryptoAdapter.isSupported = function() {
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return true;
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};
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CryptoAdapter.prototype.open = function(callback) {
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this.provider.open(callback);
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};
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CryptoAdapter.prototype.getReadOnlyContext = function() {
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return new CryptoContext(this.provider.getReadOnlyContext(),
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this.encrypt,
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this.decrypt);
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};
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CryptoAdapter.prototype.getReadWriteContext = function() {
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return new CryptoContext(this.provider.getReadWriteContext(),
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this.encrypt,
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this.decrypt);
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};
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return CryptoAdapter;
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}
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return {
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AES: buildCryptoAdapter('AES'),
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TripleDES: buildCryptoAdapter('TripleDES'),
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Rabbit: buildCryptoAdapter('Rabbit')
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};
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});
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