PBS

The Double Transposition Cipher

This was one of the most secure hand ciphers used in the Second World War. It was used by both the Allies and the Axis, and served both well. Its main weakness was that if the attacker intercepted two ...
insider.si.edu

The mathematics of secrets : cryptography from Caesar ciphers to digital encryption / Joshua Holden

Introduction to ciphers and substitution. Alice and Bob and Carl and Julius: terminology and Caesar Cipher ; The key to the matter: generalizing the Caesar Cipher ; Multiplicative ciphers ; Affine ...
The Conversation

We decrypted messages from the Biafran war that have remained secret for 50 years

Frode Weierud is affiliated with Crypto Cellar Research a privately owned company offering consultation and research in the field of cryptology. This work has been supported by the Swedish Research ...
PBS

The Double Playfair Cipher

The Double Playfair is an extension of the Playfair to use two separate keys and to encipher each pair of letters twice. The German police made the mistake in late 1941 of switching from the rather ...