Patent Document ID: 7743252
Application ID: 11454262
Patent Flag: 1

Claim One:
1. A computer-implemented method for providing authentication as to whether or not elements possess a pre-specified property, each element being operable to acquire the property and/or to lose the property, wherein the authentication is to be provided in each of a plurality of consecutive periods of time, the method comprising: generating, by a computer system, a plurality of pieces of authentication data c j (E 1 ) for said periods of time for an element E 1 which is one of said elements, each piece c j (E 1 ) being evidence that the element E 1 possesses said property in the respective period j; assigning an integer p E1 to the element E 1 ; generating, by the computer system, an encryption key K j (E 1 ) for each period j for the element E 1 , the encryption key K j being generated from a p E1 -th root u(j) 1/p E1 (mod n) of an integer u(j) modulo a predefined composite integer n, where u(j) depends on j; encrypting, by the computer system, at least part of each piece c j (E 1 ) with the respective key K j (E 1 ).