His research focuses on cryptanalysis, cryptography, security, and privacy. Orr's work in symmetric-key cryptanalysis includes analyzing many ciphers and the introduction of several new cryptanalytic techniques. Orr has worked on many of the most widely deployed ciphers such as the AES, KASUMI (used in 3G mobile networks), A5/1 (used in GSM networks), and IDEA. He served in more than 60 conference committees, including CCS, Crypto and Eurocrypt, three times as a program chair (FSE 2009, CT-RSA 2012, SAC 2015), and has won several distinctions and awards (e.g., the Krill prize (2014), best paper awards in Crypto 2012 and FSE 2012).