Practical parallel AES algorithms on cloud for massive users and their performance evaluation

Many e-business or social-network servers have been constructed on cloud. On such open environments, private data of massive users have to be protected by encrypting, such as using AES (Advanced Encryption Standard), and furthermore, this process must be finished in short time for users’ better experience. This gives huge pressure on cloud servers, especially common servers, such as web servers. We urgently need an inexpensive and highly efficient method to relieve cloud servers’ pressure. Fortunately, many cores of GPU (Graphics Processing Unit) can undertake this hard mission because of stronger computing power and lower price. The GPU environments can be virtualized on demand by cloud through the vCUDA technology. Of course, for those clouds not equipped with GPU, CPU (Central Processing Unit) can still work as multi-threads in parallel. Thus in a cloud, AES can be parallelized using many cores of GPU or multi-cores of CPU with high efficiency and low cost. For typical cloud applications, such as web services, there are massive users and each one has short plaintext. If we simply parallelize AES in such an application, we cannot obtain better performance because of GPU’s extra data transferring cost. Thus we coalesce the massive users’ data and cut these data into same length slices for improving the performance of parallel AES as much as possible. So we design six parallel AES algorithms using GPU parallelism or CPU parallelism, which differ in parallel scope and whether data are coalesced or cut to slices. Specifically, they are GCS (Coalescent and Sliced GPU), GCNS (Coalescent and Unsliced GPU), GNC (Uncoalescent GPU), CCS (Coalescent and Sliced CPU), CCNS (Coalescent and Unsliced CPU), and CNC (Uncoalescent CPU). Moreover, we implement them on two representative platforms and evaluate their performance. Through comparing their performance, GCS has the best performance among these algorithms. In a cloud with Nvidia GPUs, GCS is a more powerful algorithm for massive users’ data encrypting relatively.