First Demonstration of Homomorphic Encryption using Multi-Functional RRAM Arrays with a Novel Noise-Modulation Scheme

Homomorphic encryption (HE) is an encryption technology of which encryption and decryption process can be summarized as polynomials modulo multiplication computing with noise. In this paper, HE is firstly implemented on resistive random-access memory (RRAM) arrays, which are utilized as both matrix-vector multiplication (MVM) units and true random number generators (TRNG). Both high stability and good randomness are achieved for MVM and TRNG, respectively, by using different forming schemes, so that two distinct functions can be realized using the same device. Furthermore, the encryption-decryption process for privacy-preserving cloud computing is experimentally implemented on a hardware system with eight 144Kb RRAM arrays. For the whole RRAM array-based encryption-decryption process, small accuracy losses of 0.73% (for SVM) and 1.9% (for CNN) are achieved. This is the first demonstration of encryption computing acceleration with emerging device technology.