Side-channel attack resilient implementation of homomorphic encryption using elliptic curve cryptography for secure cloud computing

Abstract

In recent times, the amount of data exchanged between the cloud storage and the users has proliferated. The security of that data is also critical. To secure that data and to enhance its integrity, it should be encrypted before being uploaded into the cloud. In this work, a side-channel attack-secured additive homomorphic encryption is implemented using elliptic curve cryptography on an FPGA platform. An elliptic curve scalar multiplication, which is the critical component of elliptic curve cryptography, is designed in the general prime field using standard projective coordinate representation and implemented for 192, 224, and 256 bits as per the left-to-right double-and-add algorithm using radix-4 Booth-encoded modular multipliers in both FPGA devices and the ASIC platform. A minimum of 8242 slices is required to implement the proposed 256-bit elliptic curve scalar multiplication in the Virtex-6 FPGA device. The area of the proposed 192, 224, and 256-bit elliptic curve scalar multiplication is estimated as 149.225K, 208.178K, and 266.981 KGE in the ASIC using Cadence gpdk-45 nm technology libraries. A correlation power analysis attack is mounted on the FPGA implementation of the proposed elliptic curve scalar multiplication with an 8-bit data size to determine the value of scalar ‘n’. The attack is successful with a minimum of 2301 traces, and a high correlation coefficient value is obtained. Scalar randomization is proposed and integrated with the design as a countermeasure part to thwart the correlation power analysis attack, which is successful, and hence the left-to-right double-and-add algorithm used to determine elliptic curve scalar multiplication is made secure against side-channel attacks. This secured hardware implementation of elliptic curve cryptography is utilized to encrypt the data uploaded to the cloud, where additive homomorphic encryption is employed to process the data. Hence, additive homomorphic encryption becomes side-channel attack resilient, and cloud computations are secured.