// This is the key we want to transmit to another party
KeyGenerator kg = KeyGenerator.getInstance("DESede");
Key sharedKey = kg.generateKey();
// We'll transmit it with PBE encryption, which is good for
// sending keys but not arbitrary data
String password = "Come you spirits that tend on mortal thoughts";
byte[] salt = { (byte) 0xc9, (byte) 0x36, (byte) 0x78, (byte) 0x99,
(byte) 0x52, (byte) 0x3e, (byte) 0xea, (byte) 0xf2 };
PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 20);
PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray());
SecretKeyFactory kf = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey passwordKey = kf.generateSecret(keySpec);
Cipher c = Cipher.getInstance("PBEWithMD5AndDES");
c.init(Cipher.WRAP_MODE, passwordKey, paramSpec);
byte[] wrappedKey = c.wrap(sharedKey);
// Now we'll initialize a cipher with the DESede key and encrypt
// some data with it
c = Cipher.getInstance("DESede");
c.init(Cipher.ENCRYPT_MODE, sharedKey);
byte[] input = "Stand and unfold yourself".getBytes();
byte[] encrypted = c.doFinal(input);
// Now we'll try to read the wrapped key and the encrypted data
// First, we have to unwrap the key
c = Cipher.getInstance("PBEWithMD5AndDES");
// We'll reuse the key and param spec from before, but generally
// we'd have to recreate it from the password
c.init(Cipher.UNWRAP_MODE, passwordKey, paramSpec);
Key unwrappedKey = c.unwrap(wrappedKey, "DESede", Cipher.SECRET_KEY);
// Now we can use the unwrapped key to decrypt the data
c = Cipher.getInstance("DESede");
c.init(Cipher.DECRYPT_MODE, unwrappedKey);
String newData = new String(c.doFinal(encrypted));
System.out.println("The string was " + newData);
