The Double Playfair Cipher Back to Crack the Ciphers The Double Playfair is an extension of the Playfair to use two separate keys and to encipher each pair of letters twice.

End-to-end encryption is a system of communication where the only people who can read the messages are the people communicating. No eavesdropper can access the cryptographic keys needed to decrypt ...

Quantum encryption rests on the idea that if two parties share a secret key, they can scramble a message so that only they can decode it.