Constant time algorithms in PQC

In my research, I looked at the security of post-quantum algorithms. One important fundamental building block in the field of physical security is constant time algorithmic behavior. The algorithmic runtime must not differ based on secret data. Therefore several simple routines can be found in reference source code which implement trivial behavior in a sophisticated manner.

I will show several routines utilizing bitwise operations to achieve constant time behavior. Finally, I will specify the desired behavior for one function and we will develop it together.