US Patent 7841525 Digital ticketing system and method

In a digital ticketing system, tickets are created in groups. All the digital tickets in a group share a common signature value, but each ticket in the group has a unique seed value, which may be a random number. The common signature value is derived from hashing all the seed values in the group and then digitally signing a combination of the hash values. In one example, the hash values are concatenated and encrypted with a private key to generate the common signature value. The system may be implemented and tickets exchanged using mobile devices, such as mobile telephones.