PhD

Following my new passion for cryptography

Besides my passion for database systems, I am keen on cryptography, that's, algorithmic cryptanalysis, cryptographic Boolean functions, planar functions, APN functions, number theory, finite fields, stream ciphers, and other algebraic aspects of cryptography. Since I am more interested in the mathematical side of cryptography, I did my dissertation on cryptography, as part of my Master in Advanced Computer Science at Loughborough University in 2018, namely, research on cryptographic Boolean functions to prevent algebraic attacks. I am currently doing a PhD in Computer Science (cryptography) at Loughborough University, UK.

Research Areas: Cryptographic Boolean functions, planar functions, APN functions, number theory, finite fields, stream cyphers, algebraic aspects of cryptography. Also, database query processing, distributed database systems, database security, database performance, database reliability engineering.

Boolean functions are used as components in the design of many symmetric ciphers (for example, S-boxes for block ciphers like AES, or the non-linear component of stream ciphers). These functions have to satisfy certain properties to resist known cryptographic attacks. More precisely, block ciphers and stream ciphers have to face multiple types of attacks such as differential attacks and algebraic attacks, respectively. These attacks exploit vulnerabilities in some properties of Boolean functions. 

Therefore, my PhD studies are intended to work out some solutions to make cryptography Boolean function properties resistant to certain attacks. Also, in this project, I consider a family of such properties, called PN (Perfect Non-linear), APN (Almost Perfect Non-linear) and GAPN (Generalised APN). There are some well-known functions with these properties, but recently new methods of constructing such functions have been proposed, involving a combination of theoretical results and computer search. I aim to further develop these methods and obtain new such functions.

I make massive use of C programming language for cryptography — I also had experience using others languages such as Assembly, Borland Turbo C++; Visual Basic 6.5, Visual Basic .NET, Visual C# .NET, Java, T-SQL, Python, etc.

For more information on my PhD, you can have a look at 

https://www.lboro.ac.uk/departments/compsci/pg-research/phd/students/percy-reyes/