-- the state of the project as of August 8th 2010 --

• In public beta, though still using (easy to get) invitations to control the system load

• Core time stamping is fully operational, see for example https://beta.certtime.com/archive/211-676-382

• Comprehensive FAQ - https://beta.certtime.com/faq

-- the original post from October 2009 --

I hereby present to you a poor man's version of logo time-stamping.

The logo is embedded into an .exe file and the file is signed with so-called code signing cryptographic key. These keys are available to general public, but they are meant for and are almost exclusively used by the software development companies.

Interestingly enough this adds not only a cryptographic signature (if you don't know what it is, don't worry), but also a timestamp of the operation. Moreover the timestamp is then counter-signed by Verisign, which is as big and trustworthy as it gets in electronic signing business. The counter-signing means that Verisign confirms that the specific version of the file existed at a specific point in time, and latter is recorded in a timestamp that is attached to the file. Since the logo is an integral part of the file, the time stamp automatically confirms that it also existed in recorded time.

Once signed, anyone can right-click on the .exe file in Windows Explorer, select Properties and look at the Digital Signatures tab:

That's the time that the logo embedded in the .exe is guaranteed to have had existed at.

If anyone wants to check this out in detail, here is a sample .exe file (56 KB). "Save as" it and look at its Properties. If you run it, it will just show the PNG of the embedded logo:

What I'd like to know though .. let say there's an web service that allows anyone to generate such .exe files and perhaps reliably store and manage their copies. Will any of you guys be interested in this at all ? Obviously the litigation support is not to be included :-)

Alex

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Last edited by epsilon (Aug 09 - 5:38 am)