Signing paper

Although many aspects of business have moved onto computer systems, there is still a requirement in many areas to produce hardcopy evidence. Often this is signed, however it is often difficult to prove when documents are signed as it's possible to sign at a latter date, but change the date to earlier.

I wonder whether its possible to produce a digital date stamp, that has an inbuilt clock updated by RF.The stamp would include the time, date, timezone, employee reference, etc. Obviously such a stamp couldn't eliminate fraud, but it could make it more difficult.