Verification of electronic signatures

US7904725B2 · kind B2 · utility

Assignee

• Microsoft Corporation · US

Inventor

• Miladin Pavlicic · Sammamish, US

Key dates

• Filing date: Mar 2, 2006
• Grant date: Mar 8, 2011
• Expiry date: Nov 13, 2028

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L2209/56
• WIPO field: IT methods for management
• WIPO sector: Electrical engineering

Abstract

A system verifies an electronic signature. The electronic signature may be associated with timestamps, each including a time value. A timestamp verification module detects invalid certificates in a certificate chain of the electronic signature and records an earliest invalidity time value of the invalid certificates. The verification module also verifies the timestamps associated with the electronic signature and records the time value of the earliest valid timestamp. A declaration module declares the electronic signature as valid if the time value of the earliest valid timestamp is earlier than the earliest invalidity time value of the one or more invalid certificates. The electronic signature may alternatively or additionally be associated with countersignatures. A countersignature verification module verifies the countersignatures associated with the electronic signature, and the declaration module declares the electronic signature as valid if all of the countersignatures are determined to be valid.