May 6, 2022 - Reading time: 2 minutes
The people always wonder, is there any way to design uncrackable cipher? Short answer is yes. But in practice, there is no way to use them.
We need to an array which contains random characters and also you need give the key to who is you communicating.
|One-time Pad (key)||101111010110101|
If the attacker can get two crypted texts (C1, C2) which them encrypt with the same key, they he/she can use the fallowing method to decrypt the message:
C1 ⊕ C2 = (P1 ⊕ K) ⊕ (P2 ⊕ K) = P1 ⊕ P2
Later, frequency analysis or repetition in language can possible used to crack all or biggest part of P1 and P2.
⊕: Symbol of XOR
Venona Project: At the World War II, the United States was tried to crack Soviet encryption. They succeeded. Because they used the same or non-random keys for messages. So they get thousend of plain texts from crypted messages.
In the past Washington and Moscow had transferred the one-time pads to each other. They will use them if the current chipers are cracked.