National Institute of Standards and Technology (NIST)

Jeudi 07 décembre, 15:30-16:30, Salle 3195, Pavillon André-Aisenstadt

The NIST Beacon is a public source of randomness. It posts bit strings in blocks of 512 bits every 60 seconds. Each such value is time-stamped and signed to form a packet that also includes the hash of the previous value. This prevents all parties, even the source, from retroactively changing an output packet without being detected. At any point in time, the full history of outputs is available to users.

The NIST Beacon expands the use of randomness to multiple scenarios in which private random numbers cannot be conveniently used. The extra functionalities stem mainly from three features. First, the Beacon-generated numbers cannot be predicted before they are published. Second, the public, time-bound, and authenticated nature of the Beacon allows a user application to prove to anybody that it used truly random numbers not known before a certain point in time. Third, this proof can be presented offline and at any point in the future.

Although commercially available physical sources of randomness are adequate as entropy sources for currently envisioned implementations of the Beacon, we are working on developing a source of verifiably random sequences. In collaboration with NIST physicists, the project team aims to use quantum non-locality to build an entropy source whose unpredictability is guaranteed by the laws of physics. In 2015, a major milestone was achieved, namely, a strong loophole-free test of local realism (see www.nist.gov/news-events/news/2015/11/nist-team-proves-spooky-action-distance-really-real).

The output of the NIST Beacon contains many fields in addition to the 512 random bits. The purpose of these fields is to make it very difficult, even for insiders, to subvert the service. This talk will exploit a sample use case and will discuss the security issues which we believe we have solved as well as those that remain.

The NIST Beacon is available at https://beacon.nist.gov/home

Venez nombreux !