Abstract: For evaluating the security of cryptographic device in the risk environment full of electromagnetic analysis (EMA) adversaries,by enhancing the adversary's ability in the classical cryptographic black box model, two novel adversaries,the key recover adversary and the indistinguishability determined adversary who takes the advantage of electromagnetic emissions,were defined within the framework of physical observable cryptography model. For the former,the security is evaluated in quantity with the adversary's success ratio, and for the latter, the security is evaluated in quality with the adversary's advantage. With the metric of adversary's success ratio, the attack abilities of several EMA distinguishers were compared. These two practiccoricnted security metrics laid the foundations of further researching and developing EMA resistant cryptographic system and device.

Key words: Electromagnetic analysis, Cryptographic device, Practiccoricnted, Security metric