Instructions:

Enter a plaintext sentence in the textfield labeled "Plaintext of A:" then hit return. A random key is generated for A but is not shown in the textfield labeled "Key A:". A random key is generated for B and that is also not shown in the textfield labeled "Key B:". The double lock protocol is implemented with the XOR cipher. The encrypted message that A sends to B is intercepted by an attacker and the first intercepted byte is recorded and shown in the first textfield labeled "Attacker sees and records this:". The double encrypted message sent from B to A is also intercepted and and the first byte is shown in the second textfield labeled "Attacker sees and records this:". The final encrypted message sent from A to B is intercepted and the first byte is shown in the third textfield labeled "Attacker sees and records this:". From the intercepted information, the attacker can make a guess as to the value of A's key or B's key. The attacker makes the guess in either of the bottom-most textfields, accordingly then hits return. The result of decypting with the guessed key is shown in the textfield labeled "Attacker's decide guess:". If the guess is correct, the input message will appear in that textfield. Otherwise, garbage will appear.

Question:

Is there some more secure way to implement the double lock protocol?