Why the earliest forms of encryption are still used for super-secrets

Have you ever listened to short wave radio and heard something strange?  A station with no identification has a voice reading a long list of letters or numbers.  We call them number stations and they’ve been around since before World War II.  The funny thing is that they are still transmitting secret messages open and in the clear for anyone to intercept -but not decode.
Why?  Because this is unbeatable encryption that has been used for thousands of years and no one yet has found a way to defeat it without the key and, most likely, never will.
Earliest forms of encryption used what we call substitution ciphers.  This is where each letter in a message is replaced by a different letter to make a written message unreadable.  This is, at its core, how encryption still works today.  The first uses of substitution ciphers used what is called shifting.  This is […]