A Simple Single-Alphabet Substitution Cypher used by Julius Caesar for messages to his military commanders, over 2000 years ago.
It shifts or 'rotates' the alphabet, and so is sometimes called a Rotation Cypher (e.g. ROT-13 for a shift of 13). It is highly susceptable to letter frequency analysis and thus easily broken.
Instructions: Select a Key (Shift) value and type into either the Plain Text or Cypher Text boxes to see the encryption in action.