In encryption standards, Serpent refers to block cipher application that came second to R?ndael in Advanced Encryption Standard (AES) Contest. It was developed by Lars Knudsen, Ross Anderson and Eli Biham. Serpent has a block size of 128 bits and supports key sizes of 128, 192 and 256 bits.

In Blockchain world, Serpent, developed by Vitalik Buterin, refers to programming language that is used to write smart contracts in Ethereum. It is very similar to Python. It was deprecated as Vitalik believed that its technology has become outdated, hence has security concerns.