Adam Back is a British computer scientist and cryptographer known for his work in the field of digital currencies. He is the co-founder and CEO of Blockstream, a company that focuses on blockchain technology and its applications. Back is also recognized for inventing Hashcash, a proof-of-work system used to limit email spam and later adapted for cryptocurrencies. Back is often associated with the early development of Bitcoin, as he was mentioned in the original whitepaper by Satoshi Nakamoto. His contributions to cryptography and blockchain technology have made him a prominent figure in the cryptocurrency community, influencing the evolution of decentralized finance.