To decrypt a double transposition, construct a block with the right number of rows under the keyword, blocking off the short columns. Write the cipher in by columns, and read it out by rows.

Another is to employ a transposition cipher, in which the letters change position within the message. In this interactive, explore examples of a substitution cipher and two kinds of transposition ...

Windows 11’s most important new feature is post-quantum cryptography. Here’s why. For the first time, new quantum-safe algorithms can be invoked using standard Windows APIs.