Abstract: An homomorphic encryption technique enables one to carry on operations on encrypted messages without decrypting them, these encrypted messages being associated to unencrypted messages that belong to a discrete set consisting of pi distinct elements, with pi being an odd number, the elements of the discrete set being such that twice the difference between any two of these elements is not an integer number, said discrete set being for instance the discrete torus Tpi={?(pi?1)/2, ?(pi?1)/2+1, . . . , (pi?1)/2?1, (pi?1)/2}/pi. In particular, a specific bootstrapping procedure form such encrypted messages is disclosed. The disclosed technology concerns also an homomorphic encryption technique for carrying on operations on encrypted messages associated to unencrypted messages that belong Zp, p being equal to the product of r integer numbers pi, i=1 . . . r that are pairwise coprime. The disclosed technology concerns also associated electronic devices and systems implementing such techniques.