Abstract
Almost all of today’s security systems rely on cryptographic primitives which are typically considered to be the core part of the system. It is a basic and crucial task to realize these primitives on the underlying platforms for real-world deployments. In this thesis, we discuss a new primitive, called code based cryptography, which could serve as an alternative to currently popular public-key cryptosystems, like RSA, ECC. By analyzing such primitive from the perspective of an implementer, new algorithms are advanced for an optimized performance on reconfigurable hardware. Moreover, by implementing them and examining their side channel security on embedded systems with restricted resources, the new schemes are thoroughly investigated to be strong and secure candidates for replacing the current cryptosystems.The first and the main contribution of this work evaluates the potential of code based cryptography, namely the McEliece and Niederreiter cryptosystems. We explore the most promising proposals which include the Niederreiter encryption scheme using MDPC codes and the Niederreiter CFS-like signature scheme using LDGM codes. These proposed designs are inspected and revised accordingly to fit the embedded computing environment. In particular, we evaluate different implementing possibilities of critical cryptographic operations, e.g., decoding, constant weight coding, quasi-cyclic rotation.
The second contribution concerns the hardware security of code based cryptography. Admittedly, this part is still at its beginning. We target in this thesis the code based signature scheme using LDGM codes as a case study. By analyzing the correlation of the instantaneous power consumption of the cryptographic device and the cryptographic operations/data, weaknesses in a straightforward implementation that can plausibly leak the secret key is pointed out, followed by means of new masking techniques which efficiently overcome these weaknesses.
In summary, algorithmic level and hardware architecture level improvements are proposed for the code based cryptography. These improvements are essential for efficient and secure computations of code based cryptography on a range of FPGAs. The implementation results confirm that these code based schemes have already evolved into alternatives for the next generation of public-key cryptosystems.
| Date of Award | 15 May 2018 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Chak Chung Ray CHEUNG (Supervisor) & Wing Hong Ricky LAU (Supervisor) |