Contents 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 ; ...

A Cipher to Thomas Jefferson: A collection of decryption techniques and the analysis of various texts combine in the breaking of a 200-year-old code ...

The cipher utility allows you to do much more than encrypt and decrypt files. It also includes a number of switches that you can use to manage encryption keys and recovery certificates.

Learn how to use the Android Keystore to create and delete key pairs, and use the created keys to encrypt/decrypt blocks of text.