Signatures, Sergio and standardising the payment experience

According to The Daily Telegraph, “written signatures are dying out amid a digital revolution”. I’m going to miss them. Of course I know that when it comes to making a retail transaction, my signature is utterly unimportant. This is why transactions work perfectly well when I either do not give a signature (for contactless transactions up to £30 in the UK, for example, or for no-signature swipe transactions in the US) or give a completely pointless signature as I do for almost all US transactions.

“Fears are growing that this is potentially leaving people open to the risk of identity theft and fraud as their signatures are more easily imitated.”

From “Traditional signatures are dying out amid digital revolution”.

If I do have to provide a signature, then for security purposes I never give my own signature and for many years have always signed in the name of my favourite South American footballer who plays for Manchester City. Now it turns out that this is sound legal advice, since according to Gary Rycroft, a solicitor at  Joseph A. Jones & Co. it is an increasing problem that people people order things online but sometimes they do not show up so to acknowledge receiving something “I always sign my initials, for example, so I could prove if it wasn’t me” (because, presumably, a criminal would try to fake Gary’s signature).


Now the issue of signatures and the general use of them to authenticate customers for credit card transactions in the US has long been a source of amusement and anecdote. I am as guilty as everybody else is using the US retail purchasing experience to poke fun at the infrastructure there (with some justification, since as everybody knows the US is responsible for about a quarter of the world’s card transactions but half of the world’s card fraud) but I’ve also used it to illustrate some more general points about identity and authentication. My old friend Brett King wrote a great piece about signatures a few years ago in which he also made a more general point about authentication mechanisms for the 21st-century, referring to a UN/ICAO commissioned survey on the use of signatures in passports. A number of countries (including the UK) recommended phasing out theme-honoured practice because it was no longer deemed of practical use.

Well, signatures have gone the way of all things. In April, the US schemes stopped requiring signatures.

They were sort of defunct anyway. According to the New York Times, Walmart considers signatures “worthless” and has already stopped recording them on most transactions. Target has stopped using them too. I completely understand why, but to be honest I think I’ll miss signing for purchases in America.

Money 2020 Signature

No more signing Sergio Aquero for US credit card transactions, hello to signing Sergio Aquero for the Amazon lady who calls at my house with monotonous regularity.

If you are interested in the topic of signatures at all, there was a brilliant NPR Planet Money Podcast (Episode number 564) on the topic of signatures for payment card transactions a couple of years ago, in which the presenters asked why were we still using this pointless authentication technique.

Ronald Mann (the Colombia law professor interviewed for the show) noted that card signatures are not really about security at all but about distributing liabilities for fraudulent transactions and called signatures “eccentric relics”, a phrase I love. His point was that the system doesn’t really care whether I sign my transaction Dave Birch or Sergio Aquero: all it cares is that it can send the chargeback the right way (bank or merchant, essentially) when it comes in.

In addition to the law professor, NPR also asked a Talmudic scholar about signatures.

(The Talmud is the written version of the Jewish oral law and the rabbinic commentary on it that was completed in its current form some time in the fifth century. There are two parts to it: the oral law itself, which is known as the Mishnah, and the record of the rabbis arguing about it and what it meant, which is known as the Gemara.)

The scholar made a very interesting point about the use of these eccentric relics when he was talking about the signatures that are attached to the Jewish marriage contract, the Ketubah. He pointed out that it is the signatures of the witnesses that have the critical function, not the signatures of the participants, because of their role in dispute resolution. In the event of dispute, the signatures were used to track down the witnesses so that they can attest as to the ceremony taking place and as to who the participants were. This is echoed in that Telegraph article, where it notes that the use of signatures will continue for important documents such as wills, where a witness is required.

(The NPR show narrator made a good point about this, which is that it might make more sense for the coffee shop to get the signature of the person behind you in the line than yours, since yours is essentially ceremonial whereas the one of the person behind you has that Talmudic forensic function.)

The Talmudic scholar also mentioned in passing that according to the commentaries on the text, the wise men from 20 centuries ago also decided that all transactions deserved the same protection. It doesn’t matter whether it’s a penny or £1000, the transaction should still be witnessed in such a way as to provide the appropriate levels of protection to the participants. Predating PSD2 by some time, the Talmud says that every purchase is important and requires strong authentication.

So, my interpretation of the Talmud is that it is goodbye to contactless and goodbye to stripe and goodbye to chip and PIN and hello to strong authentication (which may be passive or active) and secure elements: we have the prospect of a common payment experience in store, on the web and in-app: you click “pay” and if it’s for a couple of quid the phone will just figure hey it’s you and authenticate, if it’s for a few quid your phone will ask you to confirm and can use your finger or your face and then if it’s for a few million quid you’ll get a callback for voice recognition and a retinal scan. The same purchase experience for everything: the cup of coffee and the pair of shoes and the plane ticket. It turns out that once again we can go back to the future in the design of our next retail payments system.

Brazil? Ah, I get it…

I was as alarmed as I am sure all of you were to read a story in Computing telling how EMV cards could be cloned with malware. Now, as you might imagine, were this to be true it would be a matter of the highest priority in the world of card issuers. If EMV cards could be cloned (spoiler alert: they can’t) then the whole world of payment cards would collapse. Since my I spend some of my time in that world, yet hadn’t heard anything about this catastrophic turn of events, I was naturally curious as to the accuracy of the report. Delving further into the “news” story, I found the interesting qualification that the fake cards work “on virtually any Brazilian POS system”.

Brazilian POS systems? What? Ah, wait… Now I know that they are talking about. Sadly, this yonks old hack won’t work in most places any more. But it does work in a few remaining places, and Brazil is one of them. Why? Well because Latin America, an early adopter of EMV, is still heavily reliant on “static data authentication chips”, which allow the criminals exploiting them to create usable new chip cards with the data that they can extract.

Thus problem isn’t that “EMV cards” can be cloned. They can’t. The problem is the use of Static Data Authentication (SDA) in EMV. We all knew about this many years ago. In fact, although lots of people knew about this, at the time we thought it would have been irresponsible to blog about it, so I put it to one side until stimulated by an enquiry from Brazil, I finally wrote about it back in 2014, explaining in detail what the problem was, how it was fixed and why it was no longer a worry.

So, no need to panic. Having put your mind at rest (unless you are a Brazilian card issuer, in which case my colleagues at Consult Hyperion stand ready to answer your call) I cannot resist re-telling the story that explains what the “malware” does…

Many years ago, when my colleague at Consult Hyperion were testing SDA cards in the UK, we used to make our own EMV cards. To do this, we essentially we took valid card data and loaded it onto our own Java cards. These are what we in the business call “white plastic”, because they are a white plastic card with a chip on it but otherwise completely blank. Since our white plastic do-it-yourself EMV cards could not generate the correct cryptogram (because you can’t get the necessary key out of the chip on the real card, which is why you can’t make clones of EMV cards), we just set the cryptogram value to be “SDA ANTICS” or whatever (in hex). This is what the criminals referred to in the story are doing. Now, if the card issuer is checking the cryptograms properly, they will spot the invalid cryptogram and reject the transaction. But if they are not checking the cryptograms, then the transaction will go through.


You might call these cards pseudo-clones. They act like clones in that they work correctly in the terminals, but they are not real clones because they don’t have the right keys inside them. Naturally, if you make one of these pseudo-clones, you don’t want to be bothered with PIN management so you make it into what is called a “yes card” – instead of programming the chip to check that the correct PIN is entered, you programme it to respond “yes” to whatever PIN is entered.

We used these pseudo-clone cards in a number of shops in Guildford as part of our testing processes to make sure that issuers were checking the cryptograms properly. Not once did any of the Guildford shopkeepers bat an eyelid about us putting these strange blank white cards into their terminals. But I heard a different story from a Brazilian contact. He discovered that a Brazilian bank was issuing SDA cards and he wanted to find out whether the bank was actually checking cryptograms properly (they weren’t). In order to determine this he made a white plastic pseudo-clone card and went into a shop to try it out.


When he put the completely white card into the terminal, the Brazilian shopkeeper stopped him and asked him what he was doing and what this completely blank white card was, clearly suspecting some misbehaviour.

The guy, thinking quickly, told him that it was one of the new Apple credit cards!

Cool” said the shopkeeper, “How can I get one?”.

Voter ID is back, and this time it’s in Woking

Well, Woking is in the news. It is going to be part of a pilot scheme at the forefront of the UK’s non-existent identity non-strategy to not introduce a working digital identity infrastructure to our great nation at any time in the foreseeable future The government has decided that voters in five areas in England will be asked to take identification to polling stations at local elections next year, and Woking is one of those areas. The report doesn’t mention just how the entitlement to vote is to be established but we already know what array of high technology machine learning AI super intelligent giant killer robot world brain quantum neuro-computing systems are to be deployed, because local authorities will be invited to apply to trial different types of identification, including forms of photo ID such as driving licences and passports, or formal correspondence such as a utilities bill.

Wait, what? It’s pointless enough showing a trivially counterfeitable physical identity document to someone who can’t verify it anyway, but come on… a utilities bill? That’s where we are in 2017 in the fifth richest country in the world? In Scott Corfe’s recent Social Market Foundation report A Verifiable Success—The future of identity in the UK he highlighted what he calls the “democratic opportunity” for electronic identity verification to facilitate internet voting thereby increasing civic engagement. Well, I agree. But that’s a long way from showing a gas bill to a polling station volunteer.

(And what does ‘local authorities will be invited to apply’ really mean anyway?  They’ve already been ‘invited’ to adopt the national Gov.UK Verify identity service. Very few did, and fewer still continue, so five might be ambitious. And where they do, are we disenfranchising voters who don’t feel like forging documents if they don’t come from the mainstream demographic — a point also made in the SMF report — thus distorting the outcomes).  

Now, I’ve written before that I am in favour of electronic voting of some kind but I’m very much against internet voting, because I think that in a functioning democracy voting must remain a public act and if it is allowed in certain remote conditions then we cannot be sure that a voter’s ballot is either secret or uncoerced. I think it is possible to imagine services where trusted third parties or electoral observers of some kind use mobile phones to go out and allow the infirm or otherwise housebound to vote, but that’s not the same thing as just allowing people to vote using mobile phones. I think internet voting is a really bad idea, but I take Scott’s point about the need for digital identity. However, since we don’t have one and I don’t see any prospect of Government producing a robust one in the foreseeable future, we’re stuck with gas bills until someone gets to grip with issue.

(I should explain here for any baffled overseas readers of this blog that the United Kingdom has no national identification scheme or identity card or any other such symbol of continental tyranny, so our gold standard identity document is the gas bill. The gas bill is a uniquely trusted document, and the obvious choice for a government concerned about fraud. By the way, if for some reason you do not have a gas bill to attest to your suitability for some purpose or other, you can buy one here for theatrical or novelty use only.)

Woking Polling Station

Why is it that the government never ask me about this sort of thing? Since they don’t have an identity infrastructure, why don’t they use other people’s? I would have thought that for a great majority of the population, especially the more transient and younger portion of the electorate (e.g., my sons) social media would provide a far better means to manage this entitlement. I’ve written before that I judge it to be far harder to forge a plausible Facebook profile than a plausible gas bill, so if I turn up at the polling station and log in to the Facebook profile for David Birch (if there is a Facebook profile for a David Birch, incidentally, I can assure you that it isn’t me) then they may as well let me vote.

None of this will make the slightest difference to the central problem, of course, because the main source of electoral fraud in the UK is not personation at the polling station but fraudulently-completed postal ballots, a situation that led one British judge to call it “a system that would disgrace a banana republic”. Indeed, this is precisely what has been going on in my own dear Woking, where four people were jailed recently for electoral fraud. As far as I can understand it from reading the various reports, including the source reports on electoral fraud in the UK, the main problem is that postal votes are being completed by third parties, sometimes in bulk. No proof of identity is going to make any difference to this and so long as we allow people to continue voting by post I can’t see how the situation will improve. So: it is not beyond the wit of man to come up with alternatives to the postal vote. But that’s not what is being proposed. The UK government is not currently proposing an app or any other kind of electronic voting here, it is merely proposing to add a basic test of entitlement at the ballot box.

When this scheme was originally announced, the minister in charge of voting (Chris Skidmore) was quoted by the BBC as saying that “in many transactions you need a proof of ID” which is not, strictly speaking, true. In almost all transactions that we  take part in on a daily basis we are not proving our identity, we are proving that we are authorised to do something whether it is to charge money to a line of credit in a shop, ride a bus or open the door to an office. In these cases we are using ID as a proxy because we don’t have a proper infrastructure in place for allowing us to keep our identities safely under lock and key while we go about our business.

If we are to implement the kind of electronic identity verification envisaged by the Social Market Foundation, then what you should really be presenting at the polling station is an anonymised entitlement to vote that you can authenticate your right to use. It is nobody at the polling station’s business who you are and, in common with many other circumstances, if you are required to present your identity to enable a transaction then we have created another place where identity can be stolen from. The real solution is, of course, not about using gas bills or indeed special-purpose election ID cards, but about introducing a general-purpose National Entitlement Scheme (NES). If memory serves, I think this is what my colleagues at Consult Hyperion and I first proposed in response to a government consultation paper on a national identity scheme a couple of decades ago. Oh well.