An Investigation of Sources of Randomness Within Discrete Gaussian Sampling

This paper presents a performance and statistical analysis of random number generators and discrete Gaussian samplers implemented in software. Most Lattice-based cryptographic schemes utilise discrete Gaussian sampling and will require a quality random source. We examine a range of candidates for this purpose, including NIST DRBGs, stream ciphers and well-known PRNGs. The performance of these random sources is analysed within 64-bit implementations of Bernoulli, CDT and Ziggurat sampling. In addition we perform initial statistical testing of these samplers and include an investigation into improper seeding issues and their effect on the Gaussian samplers. Of the NIST approved Deterministic Random Bit Generators (DRBG), the AES based CTR-DRBG produced the best balanced performance in our tests

BEARZ attack FALCON: implementation attacks with countermeasures on the FALCON signature scheme

Post-quantum cryptography is an important and growing area of research due to the threat of quantum computers, as recognised by the National Institute of Standards and Technology (NIST) recent call for standardisation. Lattice-based signatures have been shown in the past to be susceptible to side-channel attacks. Falcon is a lattice-based signature candidate submitted to NIST, which has good performance but lacks in research with respect to implementation attacks and resistance. This research proposes the first fault attack analysis on Falcon and finds its lattice trapdoor sampler is as vulnerable to fault attacks as the GPV sampler used in alternative signature schemes. We simulate the post-processing component of this fault attack and achieve a 100% success rate at retrieving the private-key. This research then proposes an evaluation of countermeasures to prevent this fault attack and timing attacks on Falcon. We provide cost evaluations on the overheads of the proposed countermeasures which shows that Falcon has only up to 30% deterioration in performance of its key generation, and only 5% in its signing, compared to without countermeasures

Synthesis of novel bis-triazolinedione crosslinked amphiphilic polypept(o)ide nanostructures

Owing to their wide range of inherent functionality, hydrolytic stability, biodegradability, and low toxicity, polypeptide-based materials have been increasingly exploited for controlled drug release applications. More recently, the incorporation of poly(α-peptoid)s such as poly(sarcosine) into polypeptide-based materials has been investigated owing to their potential as naturally derived “stealth polymers.” Here the synthesis of novel amphiphilic polypept(o)ide nanoparticles is described utilizing silica templates as a macroinitiator for the ring-opening copolymerization of l-tryptophan and d/l-phenylalanine NCAs and subsequent chain extension with sarcosine NCA. These particles are subsequently crosslinked utilizing the TAD-indole “click” chemistry and the silica templates are eroded via treatment with HF yielding core crosslinked amphiphilic polypept(o)ide nanostructures. This synthetic strategy offers a unique platform to yield naturally-derived degradable core-crosslinked nanostructures, which may have the potential to be utilized in the future as delivery vehicles for hydrophobic small molecules