Cipher/ˈsaɪfər/ Definition 1 of 5Pro Tip 1/3Cryptography Basics Understand that 'cipher' in this context relates to keeping information secret through encoding. Cryptographers create ciphers to protect data. Pro Tip 2/3Historical Encryption 'Cipher' also references historical methods of secret writing used before the digital age. The ancient spy network wrote in ciphers. Pro Tip 3/3Breaking Codes In stories and history, 'breaking a cipher' refers to decoding someone else's secret messages. The detectives set out to break the enemy's cipher.