A brief look at the science of cryptology and the simple encryptions found in the Old Testament. Has a couple of examples and explains the three main transformations used.
A useful document detailing the different substitution ciphers (including the Caesar Shift) and the application of Modular Arithmetic in modern day Cryptography.
The Babington plot, which was the undoing of Mary, Queen of Scots, was one of several conspiracies against Elizabeth I that were uncovered. The Ridolfi Plot In 1571 a plot was discovered involving Philip II of Spain, Pope Pius V and the Duke of Norfolk, as well as Mary's advisor, the Bishop of Ross, and Mary herself.
An in-depth description of Julius Caesar's shift cipher and how it works. Also shows how to use frequency analysis and chi-square values to quickly break the cipher.
A breach in supposedly secure keys given to employees by private companies vindicates previous warnings by cryptographers that companies should use more difficult keys, and that companies have not been cautious enough using such keys because of their assumed security.
Very interesting article that begins with the story of Mary, Queen of Scots, and continues to speak about different techniques of encryption that are harder and harder to break. It also deals with the fact that Mary's messages were being intercepted and the article speaks about secure encryption using photons where you would know if your message was intercepted.