This is too complicated to answer in a forum post. The general idea is that no number appears in the code as-is, instead all numbers appear encrypted. You have

This is too complicated to answer in a forum post. The general idea is that no number appears in the code as-is, instead all numbers appear encrypted. You have to have a way to do "encrypted multiplication" - take two encrypted numbers, and get the encryption of their multiplication, without decrypting them in the process. Also for addition. This is called fully homomorphic encryption (finally discovered several years ago, by one of the authors of this paper). This paper builds upon that result. Edit: also, see here for a simpler technique that seems to work: https://news.ycombinator.com/item?id=6160742 https://news.ycombinator.com/item?id=6160742