Time:  9h30, Thursday,  September  24, 2015

Venue: Room 301, Building A5, Institute of Mathematics, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi.

Abstract: Starting with the work of David Chaum in the 1980s, much effort has been devoted to designing a type of electronic currency that has the advantages of cash (especially privacy and anonymity) and is secure (most crucially, money cannot be spent twice).  The most popular such "cryptocurrency" is Bitcoin, which in recent years has gained popularity and also criticism.  All of these currency systems are based on cryptographic constructions using mathematical one-way functions.  Using such functions to provide a guarantee of anonymity and at the same time security against double-spending has been a challenge.  I will describe two such systems (Bitcoin and an older one), both based on elliptic curves.