Andrew Poelstra is the director of research at Blockstream, a company founded by Hashcash creator Adam Back and 8 others in 2014 to advance the development of Bitcoin Core. 

He is a mathematician and software developer with published papers on topics such as cryptography, privacy, and bitcoin.

Poelstra is known for his research in confidential transactions and multi-signatures, and has also written the Rust-bitcoin library.

Additionally he has made contributions to Mimblewimble, the blockchain structure utilized by the privacy-focused blockchain project Grin. In 2016, he wrote a whitepaper (downloads pdf file) in addition to Grin’s founding document as a member of the project’s decentralized community. In the paper, he details Mimblewimble’s cryptographic mathematics and provides an argument for its security.