Siaw-Lynn Ng

This article describes our invention of a new poetic form based on projective geometry. In doing this we also explore the 'what ifs' in mathematics and poetry which spark the creative processes of poet and mathematician. In other words, throughout our collaboration we often asked one another, is this what it's like for you? Do you think in this way, too? How does your experience of creativity compare to mine? And often, as well, what exactly do you mean when you say...? We spent a fair amount of time and energy, for example, trying to understand one another's interpretation of 'a line'. This collaboration resulted in three poems in the new projective plane form. We also consider what might be interesting avenues for future research, such as the incorporation of octonions in poetic form.

Strong external difference families (SEDFs) are much-studied combinatorial objects motivated by an information security application. A well-known conjecture states that only one abelian SEDF with more than 2 sets exists. We show that if the disjointness condition is replaced by non-disjointness, then abelian SEDFs can be constructed with more than 2 sets (indeed any number of sets). We demonstrate that the non-disjoint analogue has striking differences to, and connections with, the classical SEDF and arises naturally via another coding application.

Strong external difference families (SEDFs) are much-studied combinatorial objects motivated by an information security application. A well-known conjecture states that only one abelian SEDF with more than 2 sets exists. We show that if the disjointness condition is replaced by non-disjointness, then abelian SEDFs can be constructed with more than 2 sets (indeed any number of sets). We demonstrate that the non-disjoint analogue has striking differences to, and connections with, the classical SEDF and arises naturally via another coding application.

When peers rate each other, they may rate inaccurately to boost their own reputation or unfairly lower another’s. This could be mitigated by having a reputation server incentivise accurate ratings with a reward. However, assigning rewards becomes challenging when ratings are anonymous, since the reputation server cannot tell which peers to reward for rating accurately. To address this, we propose an anonymous peer rating system in which users can be rewarded for accurate ratings, and we formally define its model and security requirements. In our system ratings are rewarded in batches, so that users claiming their rewards only reveal they authored one in this batch of ratings. To ensure the anonymity set of rewarded users is not reduced, we also split the reputation server into two entities, the Rewarder, who knows which ratings are rewarded, and the Reputation Holder, who knows which users were rewarded. We give a provably secure construction satisfying all the security properties required. For our construction we use a modification of a Direct Anonymous Attestation scheme to ensure that peers can prove their own reputation when rating others, and that multiple feedback on the same subject can be detected. We then use Linkable Ring Signatures to enable peers to be rewarded for their accurate ratings, while still ensuring that ratings are anonymous. Our work results in a system which allows accurate ratings to be rewarded, whilst still providing anonymity of ratings with respect to the central entities managing the system.

Private Information Retrieval (PIR) schemes allow a user to retrieve a record from the server without revealing any information on which record is being downloaded. In this paper, we consider PIR schemes where the database is stored using Minimum Storage Regenerating (MSR) codes which is a class of optimal regenerating codes providing efficient repair when a node failure occurs in the system. We analyse the relationship between the costs of privacy, storage and repair, and also construct an explicit PIR scheme that uses the MSR codes from [3] to achieve the optimal curve of the trade-off.

An announcement scheme is a system that facilitates vehicles to broadcast road‐related information in vehicular ad hoc networks (VANETs) in order to improve road safety and efficiency. Here, the authors propose a new cryptographic primitive for public updating of reputation score based on the Boneh–Boyen–Shacham short group signature scheme. This allows private reputation score retrieval without a secure channel. Using this, the authors devise a privacy‐aware announcement scheme using reputation systems which is reliable, auditable, and robust.

An announcement scheme is a system that facilitates vehicles to broadcast road-related information in vehicular ad hoc networks (VANETs) in order to improve road safety and efficiency. Here we propose a new cryptographic primitive for public updating of reputation score based on the Boneh-Boyen-Shacham short group signature scheme. This allows private reputation score retrieval without a secure channel. Using this we devise a privacy-aware announcement scheme using reputation systems which is reliable, auditable and robust.