Digital signatures hit the road

For about thirty years now, security researchers have been talking about using digital signatures in court. Thousands of academic papers have had punchlines like “the judge then raises X to the power Y, finds it’s equal to Z, and sends Bob to jail”. So far, this has been pleasant speculation.

Now the rubber starts to hit the road. Since 2006 trucks in Europe have been using digital tachographs. Tachographs record a vehicle’s speed history and help enforce restrictions on drivers’ working hours. For many years they have used circular waxed paper charts, which have been accepted in court as evidence just like any other paper record. However, paper charts are now being replaced with smartcards. Each driver has a card that records 28 days of infringement history, protected by digital signatures. So we’ve now got the first widely-deployed system in which digital sigantures are routinely adduced in evidence. The signed records are being produced to support prosecutions for working too long hours, for speeding, for tachograph tampering, and sundry other villainy.

So do magistrates really raise X to the power Y, find it’s equal to Z, and send Eddie off to jail? Not according to enforcement folks I’ve spoken to. Apparently judges find digital signatures too “difficult” as they’re all in hex. The police, always eager to please, have resolved the problem by applying standard procedures for “securing” digital evidence. When they raid a dodgy trucking company, they image the PC’s disk drive and take copies on DVDs that are sealed in evidence bags. One gets given to the defence and one kept for appeal. The paper logs documenting the procedure are available for Their Worships to inspect. Everyone’s happy, and truckers duly get fined.

In fact the trucking companies are very happy. I understand that 20% of British trucks now use digital tachographs, well ahead of expectations. Perhaps this is not uncorrelated with the fact that digital tachographs keep much less detailed data than could be coaxed out of the old paper charts. Just remember, you read it here first.

3 thoughts on “Digital signatures hit the road

  1. So we have to wait for a truck driver to be unhappy about his smart card (unlike his employer with the tacho) and a hot lawyer to take up his cause to get DS’s tested in a court….

    As you say “you read it here first” but oh boy do I want to be a fly on the wall (of the court) when it happens. I think for entertainment value alone it should be recorded on film for posterity 8)

  2. On the day you posted this, there was a large scale control of taxicabs at Amsterdam international airport (Schiphol). Eleven vehicles were found to have extra devices for altering the meters. The technical details have not yet been revealed, but the authorities say that the aim was to defraud the inland revenue service, not the customers.

    In the Netherlands, evidence in a criminal trial has to be appreciable without the aid of computers, videoplayers, etc. One reason is that a suspected person detained on remand has to prepare his or her defence without access to such technology. I suppose checking a digital signature calculation with pencil and paper would be one way to try and pass the time inside…

  3. My name is Olga and I work for a company that specializes in digital signatures.
    If you’re interested, there’s some useful background (non-commercial) information about digital signatures at FAQ page

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