Ciphers, codes and other encryption methods have been used throughout history by most civilization in some form or other to prevent non-authorized people from understanding messages. They have increased in sophistication considerably throughout history and are commonly in use today.
These 11 methods range from some of the earliest examples in history to some of the most advanced encryption techniques in history.
The Caesar Shift Cipher:the Roman Army
Its First Appearance: Unknown – Likely 1st Century AD
When It Was Cracked (if applicable): Unknown – Likely between 5th and 9th Century AD
The cipher was named in honor of Julius Caesar who, according to Suetonius, used it to encrypt military and other official messages.
As the majority of Rome’s enemies were illiterate at this time the cipher remained secure for a time. By the 9th Century AD, after the fall of Rome, records exist of methods to crack it using frequency analysis from Al-Kindi.