Time stamping data with official time e.g. for electronic signature on digital documents by using decrypted official time signal to set internal time source

摘要

The method involves supplying a local and/or global official time signal to a mobile network operator (e.g. GSM). The time is encrypted and decrypted based on the technology of the network operator before being transmitted to the customer. The decrypted official time signal is used to set an internal time source. Digital data are time-stamped with this official time signal. The time-stamped data are encrypted and provided with a digital signature.