Secret Codes and Ciphers

• The Roman Frumentarii are known to have used ciphers and codes in their communications.
• The only ciphers to have survived are the Caesar Cipher, Caesar's Box, the Polybius Square (c. 180 BCE) and the Tironian notes (an early shorthand).

Caesar Cipher

• The Caesra Cipher was an Encryption Code, a simple Substitution Cipher, used by Julius Caesar (100-44 BCE) to encode messages.
• It worked by substituting each letter with another, which was 3 letters up the alphabet

Caesar's Box

• Caesar’s Box is a cipher named after Julius Caesar, but unlikely to have been used by him.

Polybius Square

• The Polybius square was a system for simplifying Telegraphy and Cryptography, devised by the Greek Historian Polybius (c. 200-118 BCE).
• Once a message was coded it could be transmitted using Roman Signalling.

Tironian notes

• Cicero's scribe Tiro (104-4 BCE) developed a code with 4,000 symbols to record his speeches.
• It is the first known example of Shorthand and was called the ‘Tironian notes’ and lasted for over 1,000 years.

Lost Ciphers

• The grammarian Aulus Gellius in his ‘Attic Nights’  17.9.1-5. mentions a lost work by Probus (232-282 CE) on Julius Caesar’s letters which contained more complicated Ciphers.