TFHE Deep Dive - Part III - Key switching and leveled multiplications

This third blog post of the TFHE series describes some more leveled homomorphic operations and building blocks.

In the previous blog post we described how to perform homomorphic additions and homomorphic multiplications with small constants. We also described a few encodings used in TFHE.

In this post, we will continue describing some more leveled homomorphic operations and building blocks. The goal is to create a solid basis to be able to understand bootstrapping in the next blog post.

Homomorphic multiplication by a large constant

In the part II we described the GLWE homomorphic multiplication by a small constant polynomial and we said that the noise grew proportionally with respect to the size of the coefficients of the polynomial.

But what happens if we try to multiply by a large constant polynomial?

(…) Continue reading on Zama’s blog here.