Traitor Deterring Schemes
Aggelos Kiayias, Qiang Tang · 2015
We put forth a new cryptographic primitive called a Traitor Deterring Scheme (TDS). A TDS is a multi-recipient public-key encryption scheme where an authority issues decryption keys to a set of users. The distinguishing feature of a TDS is that secret-keys are issued only after the users provide some private information as a form of collateral. The traitor deterring property ensures that if a malicious coalition of users (aka "traitors") produces an unauthorized (aka "pirate") decryption device, any recipient of the device will be able to recover at least one of the traitors' collaterals with only black-box access to the device. On the other hand, honest users' collaterals are guaranteed to remain hidden. In this fashion a TDS deincentivizes malicious behavior among users.