> How am I supposed to implement bitslicing to vectorize operations in Java?

By using unsafe (not ideal), the GPGPU bindings like Aparavi/JCuda or the future GPGPU API?

Honest question. Wondering about the possibilities.

> It is purely the case that high level languages do not offer you the flexibility and control to implement side-channel free crypto.

I would say Ada is an high level language that offers C and C++ flexibility, while being safe.