What is cryptoviral extortion?
Cryptoviral extortion, which uses public key cryptography, is a denial of resources attack that was introduced in [YY96a]. It is a three-round protocol that is carried out by an attacker against a victim. The attack is carried out via a cryptovirus that uses a hybrid cryptosystem to encrypt host data while deleting or overwriting the original data in the process. The protocol is as follows: (protocol setup phase) An asymmetric key pair is generated by the virus author on a smartcard and the public key is placed within the virus. The private key is designated as “non-exportable” so that even the virus author cannot obtain it’s bit representation. Thus, the private key is generated, stored, and used on the smartcard. Ideally, the smartcard will implement two-factor security: something the virus author knows (a PIN number) and something the virus writer has (the smartcard that contains the private key). Also, the card will ideally be immune to differential power analysis, timing attacks,