Costs and security in clouds

Cloud computing has emerged as an important paradigm for deploying services and applications for both enterprises and end-users. In this chapter, we explore two important aspects of cloud computing - costs and security. We aim to answer two questions: (1) Is cloud computing a cost effective endeavor? (2) How much security can we afford in the cloud while maintaining the cost benefits of outsourcing?To answer these questions, we start by looking at the economics of computing in general and clouds in particular. Specifically, we derive the end-to-end cost of a CPU cycle in various environments and show that its cost lies between 0.5 picocents in efficient clouds and nearly 27 picocents for small enterprises (1 picocent = $1 × 10^-14), values validated against current cloud pricing. We show that cloud computing makes sense only in scenarios when the clients distance can be offset by a minimal application computation footprint. We then explore the cost of common cryptography primitives as well as the viability of their deployment for cloud security purposes. It turns out that securing outsourced data and computation against untrusted clouds is often costlier than the associated savings, with outsourcing mechanisms up to several orders of magnitudes costlier than their non-outsourced locally run alternatives.