Igor Shparlinski is an outstanding mathematician whose primary area of research is number theory, encompassing both its classical and computational aspects. He has obtained a number of new results and solved several well-known problems which despite the efforts of many distinguished researchers had remained open for decades, among them a problem of Erdos. He applied advanced methods of analytical number theory to computer science and cryptography, leading to a series of remarkable results, notably a recent rigorously proved attack on the Digital Signature Algorithm, and establishing the bit security of the Diffie-Hellman protocol. Among other distinctions, he is a recipient of the Medal of the Australian Mathematical Society.