Zdeněk Říha

Faster Randomness Testing with the NIST Statistical Test Suite

Randomness testing plays an important role in cryptography. Randomness is typically examined by batteries of statistical tests. One of the most frequently used test batteries is the NIST Statistical Test Suite. The tests of randomness should be rather fast since they usually process large volumes of data. Unfortunately, this is not the case for the NIST STS, where a complete test can take hours. Alternative implementations do exist, but are not very efficient either or they do not focus on the most time-consuming tests. We reimplemented all NIST STS tests and achieved interesting speedups in most of the tests, including the tests with the highest time complexity. Overall, our implementation runs 30 times faster than the original code.

Random number generation based on fingerprints

Current research often focuses on the design of new methods that extend the well-established role of biometrics in authentication and identification into key management and cryptography. Methods have been proposed that involve biometric-governed access to cryptographic keys, as well as methods that utilize biometric samples to derive keys for specialized encryption algorithms. The aim of this paper is to present a possible method for random number generation from repeated measurements of fingerprints as an alternative approach to the proposed applications of biometrics in cryptography, and to analyze some of its properties. Such method could provide a valuable source of ranomness in mobile devices equipped with a fingerprint scanner.

An Overview of Electronic Passport Security Features

Electronic passports include contactless chip which stores personal data of the passport holder, information about the passport and the issuing institution. In its simplest form an electronic passport contains just a collection of read-only files, more advanced variants can include sophisticated cryptographic mechanisms protecting security of the document and / or privacy of the passport holder. This paper describes security features of electronic passports and discusses their efficiency.

Algorithm 970: Optimizing the NIST Statistical Test Suite and the Berlekamp-Massey Algorithm

The NIST Statistical Test Suite (NIST STS) is one of the most popular tools for the analysis of randomness. This test battery is widely used, but its implementation is quite inefficient. A complete randomness analysis using the NIST STS can take hours on a standard computer when the tested data volume is on the order of GB. We improved the most time-consuming test (Linear Complexity) from the previous most efficient implementation of the NIST STS. We also optimized other tests and achieved an overall speedup of 50.6 × compared with the reference implementation. This means that 20MB of data can be tested within a minute using our new optimized version of the NIST STS. To speed up the Linear Complexity test, we proposed a new version of the Berlekamp-Massey algorithm that computes only the linear complexity of a sequence. This new variant does not construct a linear feedback shift register and is approximately 187 × faster than the original NIST implementation of the Berlekamp-Massey algorithm.