Think of a timestamp as a digital or electronic notary. Use it for intellectual property witnessing and document authentication. U-Sign pdf provides digital evidence that your data has not been altered nor backdated. (IETF standard RFC3161 TimeStamp Protocol )

A digital time stamp gives you unequivocal proof that the contents of your work existed at a point-in-time and that the contents have not changed since that time. Consider this a type of notary service - only updated to become a digital notary. Any file on your computer can be time stamped, regardless of its content.

The TimeStamp process consists of 2 parts:

U-Sign PDF executes on your computer when you need to TimeStamp a file. The software creates the fingerprint for your file, communicates with the TimeStamp server computer, and stores your time stamp certificates.

The Internet links you to the TimeStamp server--the trusted third party. It provides the reliable clock; and returns to you a sealed-electronic time stamp certificate that contains your file's fingerprint.

A Fingerprint

When you time stamp a file, your computer creates a unique identifier, or fingerprint, for the file (a SHA-1 Hash). The fingerprint is a unique number calculated from the file's contents. Mathematicians call this a Hash function. If the file's contents were to change by even one character, a different number would be calculated. This proven encryption technique ensures that no 2 files have the same number. Read more about the SHA-1 hash standard here.

The Internet

By using the Internet, you electronically send the file's fingerprint to the TimeStamp server computer. At the TimeStamp server, it put puts the file's fingerprint and the current time into an encrypted electronic envelope. The result is a digital time stamp certificate that is returned and stored in your PDF File.