Filtering by
- Resource Type: Text
In this thesis, first the design of a highly reliable resistive random access memory (RRAM) PUF is presented. Compared to existing 1 cell/bit RRAM, here the sum of the read-out currents of multiple RRAM cells are used for generating one response bit. This method statistically minimizes any early-lifetime failure due to RRAM retention degradation at high temperature or under voltage stress. Using a device model that was calibrated using IMEC HfOx RRAM experimental data, it was shown that an 8 cells/bit architecture achieves 99.9999% reliability for a lifetime >10 years at 125℃ . Also, the hardware area overhead of the proposed 8 cells/bit RRAM PUF architecture was smaller than 1 cell/bit RRAM PUF that requires error correction coding to achieve the same reliability.
Next, a basic security primitive is presented, where the RRAM PUF is embedded in the cryptographic module, SHA-256. This architecture is referred to as Embedded PUF or EPUF. EPUF has a security advantage over SHA-256 as it never exposes the PUF response to the outside world. Instead, in each round, the PUF response is used to change a few bits of the message word to produce a unique message digest for each IC. The use of EPUF as a key generation module for AES is also shown. The hardware area requirement for SHA-256 and AES-128 is then analyzed using synthesis results based on TSMC 65nm library. It is shown that the area overhead of 8 cells/bit RRAM PUF is only 1.08% of the SHA-256 module and 0.04% of the AES-128 module. The security analysis of the PUF based systems is also presented. It is shown that the EPUF-based systems are resistant towards standard attacks on PUFs, and that the security of the cryptographic modules is not compromised.
Many current cryptographic algorithms will eventually become easily broken by Shor's Algorithm once quantum computers become more powerful. A number of new algorithms have been proposed which are not compromised by quantum computers, one of which is the Supersingular Isogeny Diffie-Hellman Key Exchange Protocol (SIDH). SIDH works by having both parties perform random walks between supersingular elliptic curves on isogeny graphs of prime degree and eventually end at the same location, a shared secret.<br/><br/>This thesis seeks to explore some of the theory and concepts underlying the security of SIDH, especially as it relates to finding supersingular elliptic curves, generating isogeny graphs, and implementing SIDH. As elliptic curves and SIDH may be an unfamiliar topic to many readers, the paper begins by providing a brief introduction to elliptic curves, isogenies, and the SIDH Protocol. Next, the paper investigates more efficient methods of generating supersingular elliptic curves, which are important for visualizing the isogeny graphs in the algorithm and the setup of the protocol. Afterwards, the paper focuses on isogeny maps of various degrees, attempting to visualize isogeny maps similar to those used in SIDH. Finally, the paper looks at an implementation of SIDH in PARI/GP and work is done to see the effects of using isogenies of degree greater than 2 and 3 on the security, runtime, and practicality of the algorithm.
A form of nanoscale steganography exists described as DNA origami cryptography which is a technique of secure information encryption through scaffold, staple, and varying docking strand self- assembling mixtures. The all-DNA steganography based origami was imaged through high-speed DNA-PAINT super-resolution imaging which uses periodic docking sequences to eliminate the need for protein binding. The purpose of this research was to improve upon the DNA origami cryptography protocol by encrypting information in 2D Rothemund Rectangular DNA Origami (RRO) and 3D cuboctahedron DNA origami as a platform of self-assembling DNA nanostructures to increase the routing possibilities of the scaffold. The initial focus of the work was increasing the incorporation efficiency of all individual docking spots for full 20nm grid RRO pattern readout. Due to this procedural optimization was pursued by altering annealing cycle length, centrifugal spin rates for purification, and lengthening docking strands vs. imager poly T linkers. A 14nm grid was explored as an intermediate prior to the 10nm grid for comparison of optimized experimental procedure for a higher density encryption pattern option. Imager concentration was discovered to be a vital determining factor in effectively resolving the 10nm grids due to high concentrations of imager strands inducing simultaneous blinking of adjacent docking strands to be more likely causing the 10nm grids to not be resolved. A 2 redundancy and 3 redundancy encryption scheme was developed for the 10nm grid RRO to be encrypted with. Further experimentation was completed to resolve full 10nm DNA-origami grids and encrypt with the message ”ASU”. The message was successfully encrypted and resolved through the high density 10nm grid with 2 and 3 redundancy patterns. A cuboctahedron 3D origami was explored with DNA-PAINT techniques as well resulting in successful resolution of the z-axis through variation of biotin linker length and calibration file. Positive results for short message ”0407” encryption of the cuboctahedron were achieved. Data encryption in DNA origami is further being explored and could be an optimal solution for higher density data storage with greater longevity of media.
In this thesis we will examine the algorithm of the number field sieve and discuss some important advancements. In particular, we will focus on the advancements that have been done in the polynomial selection step, the first main step of the number field sieve. The polynomial selected determines the number field by which computations are carried out in the remainder of the algorithm. Selection of a good polynomial allows for better time efficiency and a higher probability that the algorithm will be successful in factoring.