On 2007/10/03 21:36, Joachim Schipper wrote: > On Wed, Oct 03, 2007 at 06:21:53PM +0200, G??bri M??t?? wrote: > > Hey there! > > > > I've read a lot about timestamping a document, but dunno how it works in > > practice. How can i apply a timestamp to a digitally signed or encrypted > > document? Like i encrypt or sign a document with gnupg, but before the > > process how can i timestamp it?
google/patent search: haber stornetta dead trees: there's a little section in Applied Cryptography (surprise!), the basics are fairly obvious (send TTP a hash, they append a timestamp and sign the lot) but to prevent collusion between sender and TTP additional measures are normally used. > The Big G is your friend [1]: > > http://www.itconsult.co.uk/stamper.htm Now it's October 2007 and RIPA part III is in force, .uk is not a great jurisdiction to be hosting cryptographic services.
