(function(){
|
|
var C = (typeof window === 'undefined') ? require('./Crypto').Crypto : window.Crypto;
|
|
// Shortcuts
|
var util = C.util,
|
charenc = C.charenc,
|
UTF8 = charenc.UTF8,
|
Binary = charenc.Binary;
|
|
var MARC4 = C.MARC4 = {
|
|
/**
|
* Public API
|
*/
|
|
encrypt: function (message, password) {
|
|
var
|
|
// Convert to bytes
|
m = UTF8.stringToBytes(message),
|
|
// Generate random IV
|
iv = util.randomBytes(16),
|
|
// Generate key
|
k = password.constructor == String ?
|
// Derive key from passphrase
|
C.PBKDF2(password, iv, 32, { asBytes: true }) :
|
// else, assume byte array representing cryptographic key
|
password;
|
|
// Encrypt
|
MARC4._marc4(m, k, 1536);
|
|
// Return ciphertext
|
return util.bytesToBase64(iv.concat(m));
|
|
},
|
|
decrypt: function (ciphertext, password) {
|
|
var
|
|
// Convert to bytes
|
c = util.base64ToBytes(ciphertext),
|
|
// Separate IV and message
|
iv = c.splice(0, 16),
|
|
// Generate key
|
k = password.constructor == String ?
|
// Derive key from passphrase
|
C.PBKDF2(password, iv, 32, { asBytes: true }) :
|
// else, assume byte array representing cryptographic key
|
password;
|
|
// Decrypt
|
MARC4._marc4(c, k, 1536);
|
|
// Return plaintext
|
return UTF8.bytesToString(c);
|
|
},
|
|
|
/**
|
* Internal methods
|
*/
|
|
// The core
|
_marc4: function (m, k, drop) {
|
|
// State variables
|
var i, j, s, temp;
|
|
// Key setup
|
for (i = 0, s = []; i < 256; i++) s[i] = i;
|
for (i = 0, j = 0; i < 256; i++) {
|
|
j = (j + s[i] + k[i % k.length]) % 256;
|
|
// Swap
|
temp = s[i];
|
s[i] = s[j];
|
s[j] = temp;
|
|
}
|
|
// Clear counters
|
i = j = 0;
|
|
// Encryption
|
for (var k = -drop; k < m.length; k++) {
|
|
i = (i + 1) % 256;
|
j = (j + s[i]) % 256;
|
|
// Swap
|
temp = s[i];
|
s[i] = s[j];
|
s[j] = temp;
|
|
// Stop here if we're still dropping keystream
|
if (k < 0) continue;
|
|
// Encrypt
|
m[k] ^= s[(s[i] + s[j]) % 256];
|
|
}
|
|
}
|
|
};
|
|
})();
|
