Verfahren zur Datenchiffrierung einer Chipkarte, zur Schlüsselerzeugung und zum Rechnen seiner Authentifizierungszeugnisse, und diese Verfahren benützende Chipkarten

摘要

The invention relates to a process for encrypting data in a microprocessor card. The card contains a set of selectable encryption keys (CSO, ..., CSn). The formula (K1,K2,A,M) -> F(K1,K2,A,M) = R = E((E(M,K1)&f(A)),K2> is applied, where: E(x,y) designates a stored cryptographic algorithm operating in a specific domain {0,1}, M denotes a datum to be encrypted fed to the microprocessor card, K1 and K2 designate two encryption keys, primary and secondary respectively, which are different or identical and are selected from the said set of keys (CSO, ..., CSn) with the aid of external selection data, A designates a datum representing the nature or origin of the encryption to be performed, f(A) designates a function for transforming the datum A such that f(A) belongs to {0,1}, and & designates a Boolean function such as the "Exclusive Or" function.