The student is also expected to study how those protocols can be combined with mixnets. The goal of the student is to survey some existing byzantine agreement protocols that are suitable for usage in e-voting. Any other modifications should be detected and declined. The standard way to achieve this is to use byzantine agreement protocols, where each modification of data goes through only if a (large) majority of storage servers agree. The first step, bulletin board, has to be implemented in a way that a malicious server could not modify the ballots, that is, it has to do the storage and updating of the data (e.g., in Estonia a voter can cast vote several times) in a verifiable manner. Solution): anonymizing the encrypted ballots, and (c) decrypting anonymized ballots. Receiving data (encrypted ballots) from voters and storing it until the end of the election period, \\ Very broadly speaking, the server-side of I-voting consists of three stages: (a) bulletin board: Since the result of elections has high influence on the whole society, it is important to guarantee that I-voting is done in a secure manner. This topic is suitable for a MSc thesis in fact, Helger Lipmaa is actively looking for a mathematically minded student who can work on this.Įstonia is the only country in the world that has nationwide Internet voting for parliament. The goal of the student is to survey some existing proposals that try to do this combination, and write a readable comparison between them.įind out what security properties are needed from the mixnet, etc. One of those solutions is to combine Bitcoin with mixnets. Several solutions have been proposed to solve this issue. One issue of Bitcoin is linkability: all transactions made by the same user can all be linked together this has been demonstrated to have very bad for user privacy. It was proposed as an ad hoc solution, but it is in a wide use, and lately the security of Bitcoin has been studied by many cryptographers. Mixnet is a means to guarantee anonymity by verifiably mixing input data so that the link between the source of the data and the data itself will be destroyed, while the data itself will not be modified or deleted.īitcoin is a well-known cryptocurrency where all transactions are linked by public ledger. This project is related to Panoramix, an H2020 project on mixnets. Tore will focus on implementing lattice-based cryptosystems using NFLlib. Springer International Publishing, 2016.Īssigned to Behzad Abdolmaleki and Tore Vincent Carstens Behzad will focus on the theory of Ring-LWE cryptosystem. "NFLlib: NTT-based fast lattice library." Cryptographers’ Track at the RSA Conference. "Making NTRU as secure as worst-case problems over ideal lattices." Annual International Conference on the Theory and Applications of Cryptographic Techniques. "On ideal lattices and learning with errors over rings." Annual International Conference on the Theory and Applications of Cryptographic Techniques. Vadim Lyubashevsky, Chris Peikert, and Oded Regev. key generation, ciphertext size, encryption and decryption times) to implementations of ElGamal and RSA with comparable security parameters (e.g. The student will then implement these cryptosystems using NFLlib, and compare various aspects (e.g. In this project, the student will survey the Ring-LWE assumption, the properties of the cyclotomic ring R = Z/(X^n + 1), where n is a power of 2, and how both are used in the LPR and NTRU lattice-based cryptosystems. The question is, how efficient are these cryptosystems? Security is based on computational problems assumed to be NP-hard in the average case, such as Ring Learning With Errors (Ring-LWE). Post-quantum public key cryptosystems are designed to be secure even against quantum adversaries. In particular, there exists quantum attacks on factoring and discrete logarithm that run in polynomial-time. Public key cryptosystems such as RSA-OAEP and ElGamal are IND-CPA secure, but not secure against quantum computers.
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