A comprehensive educational cipher toolbox for encryption and decryption, featuring both classical and modern cryptographic algorithms — now with a built-in MCP (Model Context Protocol) server for AI ...

The envelope arrived at the San Francisco Chronicle in November 1969 without a return address, its directive to the recipient, in handwriting distinctively slanted and words unevenly spaced, to ...

Substituting letter pairs (bigrams) is an encryption method that was already known in the 16th century. Is it still secure today? To develop an encryption method that only requires pen and paper is a ...

A Rubik’s Cube can be used to implement a highly secure encryption method. One of the most interesting questions in classical cryptography is the following: How can one encrypt without using a ...