Cryptographic Games

The term “game” has substantially different meanings within the security area, depending on whether we speak about cryptographic security in particular, or system security in a more general setting that includes quantitative security with help of game theory. Game theory and cryptography are, however, of mutual value for each other, since game theory can help designing self-enforcing security of cryptographic protocols, and cryptography contributes invaluable mechanisms to implement games for security. This chapter introduces both ideas, being rational cryptography for the design of protocols that use rationality to incentivize players to follow faithfully, but also addresses the classical security goals like confidentiality, integrity, availability and authenticity by describing security games with quantitative and unconditional security guarantees. The chapter closes with a connection between network design for security and the P/NP question whose discovery is made with help from game theory.