Brent Waters
American cryptographer who laid the foundations of attribute-based encryption with Amit Sahai and then built most of the house on top.
Waters earned his PhD at Princeton in 2004 under Ed Felten and worked at SRI before becoming a professor at the University of Texas at Austin, and later also at NTT Research. After the 2005 paper with Sahai the variants came quickly: key-policy ABE in 2006 and ciphertext-policy ABE in 2007, where the policy lives on the encrypted document instead.
In 2009 he introduced dual system encryption, a proof technique that let identity- and attribute-based schemes be proven secure without the artificial restrictions earlier proofs needed. He co-authored the first obfuscation candidate in 2013 and worked with Dan Boneh on constrained pseudorandom functions. A good share of the modern theory of encryption with fine-grained access carries his fingerprints.