> Even if you choose r to be small during encryption, the r values accumulate with each homomorphic operation and will eventually be too big As @tuxxy points o

> Even if you choose r to be small during encryption, the r values accumulate with each homomorphic operation and will eventually be too big As @tuxxy points out, there is a metaphor for describing this - a "noise ceiling". To see this phrase used in context, see, for example: https://eprint.iacr.org/2011/277.pdf https://eprint.iacr.org/2011/277.pdf