initital commit

2021-09-15 09:58:01 +08:00
commit d46f96d263
90 changed files with 17509 additions and 0 deletions
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+(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];
+
+		}
+
+	}
+
+};
+
+})();