Method and apparatus for identity based ticketing

An apparatus, comprising:

• memory configured to store a public key of a certificate authority;
• a communication interface configured to exchange messages with a user device;
• and
• a processor configured to:
• cause an authenticating session with the user device for authenticating using of a service by the user device;
• and
• receive from the user device one or more messages using the communication interface, wherein each of the one or more messages contains a transaction record signature, an authenticator that comprises an i times hashed seed number in which i represents a number of times that a hash function was applied to a random secret seed having a predetermined validity duration, and a distance in a hash chain of the i times hashed seed number, the distance indicative of the number of times the certificate has been used to attempt authenticating of the apparatus, the hash chain constructed by choosing the random secret seed and repeatedly applying the cryptographic hash function i times, in order to limit a number of times the certificate can be used for the authenticating of the apparatus.

A method in an apparatus, comprising:

• storing user specific credentials;
• receiving a certificate from a certificate authority;
• storing the certificate;
• storing a private key and a public key in the memory;
• and
• attempting authenticating of the apparatus to a ticket reader for accessing a service, by transmission of one or more messages, wherein each of the one or more messages contain a transaction record signature, an authenticator that comprises an i times hashed seed number in which i represents a number of times that a hash function was applied to a random secret seed having a predetermined validity duration, and a distance in a hash chain of the i times hashed seed number, the distance indicative of the number of times the certificate has been used to attempt authenticating of the apparatus, the hash chain constructed by choosing the random secret seed and repeatedly applying the cryptographic hash function i times, in order to limit a number of times the certificate can be used for the authenticating of the apparatus.