Of Ads and Signatures

Both advertisements and signatures have been with us in the analogue realm for ages, the society has learned about their usefulness and limits. We have learned that it’s (usually) hard to judge the impact of a single ad, and that the process of actually validating a contested signature is not trivial. There is a good reason why the law requires more than a single signature to authorize the transfer of real estate.

Both concepts have been translated to the digital, online world.

And in both cases, there were promises that the new, digital and online versions of ads/signatures can deliver features that their old, analogue counterparts could not do.

For ads, it was the promise of real-time tracking of their effectiveness. You could do “clickthrough rates” measuring how often the ad was clicked by a viewer. The holy grail of ad effectivity tracking is the fabled “conversion rate”: you can measure how many people actually bought your product after clicking an ad.

For signatures, it was the promise of automated validation. If you get a digitally signed document, you should be able to actually verify (and can have 100% trust in the result) whether it was really signed by the signatory. Remember: in the analogue world, almost nobody actually does this. The lay person can detect crude forgeries, but even that only if the recipient has access to samples of authentic signatures. In reality, a closer inspection of handwritten signatures is only done for important transactions, or in the case of a dispute.

So how did things work out after a few years of experience with digital ads and signatures?

Digital ads are in a midlife crisis. We’re in a death spiral of low clickthrough rates, more obnoxious formats, ad-blockers and ad-blocker-blockers. Just look at the emergence of Taboola and similar click-bait.
Digital signatures are at a cross-road as well: The take-up rates of solutions based on smart-card readers have been underwhelming so far. This applies to the German ePerso as well as to the Austrian citizen card. The usability just isn’t there. So there has been a push to increase the take-up rate by introducing alternatives to smart-card technology. That won’t make it more secure. Not at all.

So what’s the common lesson? In theory, both digital ads and signatures can offer features that their old, analogue counterparts just cannot deliver. In practice, they are killing themselves by over-promising. As long as click-through rates are the prime measurement of online ads, their death spiral will continue. And as long as digital signatures continue to promise instant, high-confidence validation, they will not achieve the take-up rates needed for broad acceptance.

Continuing the current trajectory will lead to a hard crash for both technologies. On one side it’s the ad-blocker, on the other side it’s malware.

The level of spam in the email ecosystem meant that no mail-service can exist in the market without a built-in spam-filtering solution. And given the early ad-excesses every browser includes a pop-up blocker these days. If the advertisers continue on their path of getting attention at all costs, ad-blocking will become a must-have feature in all browsers, and not just an optional ad-on (as right now).

Any digital security solution that protects actual money has been under vigorous attack. The cat and mouse game between online-banking defenders and attackers is a good lesson. The same will happen if digital signature solutions start to be actually relevant. And good luck if your “let’s make digital signatures more user-friendly” approach is actually less secure than what online-banking is using these days.

So what’s the solution?

In my opinion the right way to approach both topics is to reduce the promise. Make digital ads static images. No animation. No dynamic loading of js-code (which is its own security nightmare). Don’t overtax the visitor’s resources (bandwidth, browser-performance). No tracking. Tone it down. Don’t expect instant effects. Don’t promise clicktrough rate.

For digital signatures: Mass deployment is only possible for “non-qualified signatures”. Don’t promise “you can fully and solely rely on our solution”. Just sell “this is a good indication”, or “use this as one factor in your security design”. Prepare for it to be attacked and broken. Only use it when you have a pre-planned way to recover from such a breach. The real word is full of applications where signatures are used in a very low-security / low-impact settings. The state-sponsored digital identity solutions needs to think of those, too. For the high-impact, high-confidence settings I always have to think about the mantra we use at work: “You can’t mandate trust.”