PhD Positions in Applied Cryptology, Worcester Polytechnic Institue, MA, USA
The Vernam Group for Security and Privacy at WPI in Worcester, MA has open PhD positions in applied cryptology. In particular there are two openings in side channel analysis and leakage resilient implementation.
Candidates should have a Master’s degree in electronics, computer science or applied mathematics, with strong interest in algorithms and signal processing. Prior experience in side channel analysis and embedded software or hardware design is an asset.
We offer a competitive salary and an international cutting-edge research program in an attractive working environment. WPI is one of the highest-ranked technical colleges in the US. Located in the greater Boston area, it maintains close interaction with many of the nearby universities and companies.
Continuous Non-malleable Codes, by Sebastian Faust and Pratyay Mukherjee and Jesper Buus Nielsen and Daniele Venturi
Non-malleable codes are a natural relaxation of error correcting/detecting codes that have useful applications in the context of tamper resilient cryptography. Informally, a code is non-malleable if an adversary trying to tamper with an encoding of a given message can only leave it unchanged or modify it to the encoding of a completely unrelated value. This paper introduces an extension of the
standard non-malleability security notion - so-called continuous non-malleability - where we allow the adversary to tamper continuously with an encoding. This is in contrast to the standard notion of
non-malleable codes where the adversary only is allowed to tamper a single time with an encoding. We show how to construct continuous non-malleable codes in the common split-state model where an encoding consist of two parts and the tampering can be arbitrary but has to be independent with both parts. Our main contributions are outlined below:
1. We propose a new uniqueness requirement of split-state codes which states that it is computationally hard to find two codewords C = (X0;X1) and C0 = (X0;X1\') such that both codewords are valid, but X0 is the same in both C and C0. A simple attack shows that uniqueness
is necessary to achieve continuous non-malleability in the split-state model. Moreover, we illustrate that none of the existing constructions satisfies our uniqueness property and hence is not secure in the continuous setting.
2. We construct a split-state code satisfying continuous non-malleability. Our scheme is based
on the inner product function, collision-resistant hashing and non-interactive zero-knowledge
proofs of knowledge and requires an untamperable common reference string.
3. We apply continuous non-malleable codes to protect arbitrary cryptographic primitives against tampering attacks. Previous applications of non-malleable codes in this setting required to
perfectly erase the entire memory after each execution and and required the adversary to be restricted in memory. We show that continuous non-malleable codes avoid these restrictions.