<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000'><b>This even has been postponed. A new date/time will be announced as soon as the information becomes available. </b><br><br><hr><br><br><br>Decentralized Anonymous Credentials and Electronic Payments from Bitcoin <br>Matthew Green, John Hopkins University <br>Tuesday, October 21 , 4:30pm <br>Computer Science 105 <br><br><br>Traditionally,
making statements about identity on the Internet, whether literal
assertions of identity or statements about one’s identity, requires
centralized providers who issue credentials attesting to the user’s
information. These organizations, which include Certificate Authorities,
DNS maintainers, or login providers like Google and Facebook, play a
large role in securing internet infrastructure, email, and financial
transactions. Our increasing reliance on these providers raises concerns
about privacy and trust. <br><br>Anonymous credentials represent a
powerful solution to this privacy concern: they deprive even colluding
credential issuers and verifiers of the ability to identify and track
their users. Although credentials may involve direct assertions of
identity, they may also be used for a large range of useful assertions,
such as “my TPM says my computer is secure”, “I have a valid
subscription for content”, or “I am eligible to vote.” Anonymous
credentials can also be used as a basis for constructing untraceable
electronic payment systems, or “e-cash". <br><br>Unfortunately most
existing anonymous credential and e-cash systems have a fundamental
limitation: they require the appointment of a central, trusted party to
issue credentials or tokens. This issuer represents a single point of
failure and an obvious target for compromise. In distributed settings
such as ad hoc or peer-to-peer networks, it may be challenging even to
identify parties who can be trusted to play this critical role. <br><br>In
this talk I will discuss new techniques for building anonymous
credentials and electronic cash in a fully decentralized setting. The
basic ingredient of these proposals is a "distributed public append-only
ledger", a technology which has most famously been deployed in digital
currencies such as Bitcoin. This ledger can be employed by individual
nodes to make assertions about a user’s attributes in a fully anonymous
fashion — without the assistance of a credential issuer. One concrete
result of these techniques is a new protocol named “Zerocash”, which
adds cryptographically unlinkable electronic payments to the Bitcoin
currency. <br><br>Prof. Matthew Green is a Research Professor at the
Johns Hopkins University Information Security Institute. His research
focus is on cryptographic techniques for maintaining users’ privacy, and
on technologies that enable the deployment of privacy-preserving
protocols. From 2004-2011, Green served as CTO of Independent Security
Evaluators, a custom security evaluation firm with a global client base.
Along with a team at Johns Hopkins and RSA Laboratories, he discovered
flaws in the Texas Instruments Digital Signature Transponder, a
cryptographically-enabled RFID device used in the Exxon Speedpass
payment system and in millions of vehicle immobilizers. <br><br></div></body></html>