The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 21, 2021
Filed:
Jun. 27, 2018
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A method for producing a cryptographic timestamp for a digital document using multiple time servers is provided. In the method, a nonce value is produced and a current hash value is formed from the nonce value and the digital document. Then, a time server is repeatedly selected, the current hash value is transmitted to the selected time server, a response comprising a digital signature of the current hash value and a time indication is received by the selected time server, and an additional hash value is determined from the received response and used as the current hash value. The cryptographic timestamp for the digital document is formed from the nonce value and the multiple received responses. The method produces a tamperproof timestamp on a majority basis and is suitable for dating and protocolling in the field of automation and IoT.