Cardless Cashpoints

My mobile banking app, showing me a special six digit code.
The mobile app presents you with a special six-digit code that is used to withdraw the cash.

RBS Group this week rolled out a service to all of its customers, allowing them to withdraw cash from an ATM without using their bank card. The service is based upon the same technologies that’s used to provide emergency access to cash by people who’ve had their cards stolen, but integrates directly into the mobile banking apps of the group’s constituent banks. I decided to give it a go.

The first step is to use the mobile app to request a withdrawal. There’s an icon for this, but it’s a bit of a mystery that it’s there unless you already know what you’re looking for. You can’t make a request from online banking without using the mobile app, which seems to be an oversight (in case you can’t think of a reason that you’d want to do this, read on: there’s one at the end). I opted to withdraw £50.

Next, it’s off to find a cash machine. I struck out, without my wallet, to try to find the nearest Royal Bank of Scotland, NatWest, or Tesco cashpoint. The mobile app features a GPS tool to help you find these, although it didn’t seem to think that my local Tesco cashpoint existed, walking me on to a branch of NatWest.

Cash machine: "Do you wish to carry out a Get Cash or Emergency Cash transaction? [No] [Yes]"
The readout of the cash machine demonstrates that the roots of the “Get Cash” system lie in the older “Emergency Cash” feature: the two are functionally the same thing.
As instructed by the app, I pressed the Enter key on the keypad of the cash machine. This bypasses the usual “Insert card” prompt and asks, “Do you wish to carry out a Get Cash or Emergency Cash transaction?” I pressed Yes.

Entering a 6-digit code from a mobile phone into a cash machine.
The number displayed upon the screen is entered into the cash machine.

The ATM asked for the PIN I’d been given by the mobile app: a 6-digit code. Each code is only valid for a window of 3 hours and can only be used once.

A cashpoint asking for the PIN a second time, and then asking for the amount of money to withdraw.
The cash machine asks for the PIN a second time, and then asks for the sum of money to be withdrawn.

I’m not sure why, but the ATM asks that the PIN is confirmed by being entered a second time. This doesn’t make a lot of sense to me – if it was mistyped, it’d surely fail anyway (unless I happened to guess another valid code, within its window), and I’d simply be able to try again. And if I were an attacker, trying to guess numbers, then there’s no difficulty in typing the same number twice.

It’s possible that this is an attempt at human-tarpitting, but that wouldn’t be the best way to do it. If the aim is to stop a hacker from attempting many codes in quick succession, simply imposing a delay would be far more effective (this is commonplace with cash machines anyway: ever notice that you can’t put a card in right after the last transaction has finished?). Strange.

Finally, the ATM asks what value of cash was agreed to be withdrawn. I haven’t tried putting in an incorrect value, but I assume that it would refuse to dispense any cash if the wrong number was entered – this is presumably a final check that you really are who you claim to be.

Cash machine: "Please take your cash and your receipt."
It feels strange taking money and a receipt from a cashpoint without first having to retrieve my card. I spent a few minutes after the experience with a feeling that I’d forgotten something.

It worked. I got my money. The mobile app quickly updated to reflect the change to my balance and invalidated the code: the system was a success.

The banks claim that this will be useful for times that you’ve not got your card with you. Personally, I don’t think I ever take my phone outdoors without also taking my wallet with me, so the chance of that it pretty slim. If my card were stolen, I’d be phoning the bank to cancel the card anyway, so it wouldn’t save me a call, either, if I needed emergency cash. But there are a couple of situations in which I’d consider using this neat little feature:

  • If I was suspicious of a possible card-skimming device on a cash machine, but I needed to withdraw money and there wasn’t an un-tampered ATM in the vicinity. It’d be nice to know that you can avoid having your card scanned by some kid with a skimmer just by using your phone to do the authentication rather than a valuable piece of plastic.
  • To send money to somebody else. Using this tool is cheaper than a money order and faster than a bank transfer: it’s an instantaneous way to get small sums of cash directly into the hands of a distant friend. “Sure, I’ll lend you £50: just go to a cash machine and type in this code.” I’m not sure whether or not this is a legitimate use of the service, but I can almost guarantee that it’ll be the most-popular. It’ll probably be reassuring to parents of teenagers, for example, who know that they can help their offspring get a taxi home when they’ve got themselves stranded somewhere.

What do you think? If you’re with RBS, NatWest or Tesco, have you tried this new mobile banking feature? Do you think there’s mileage in it as an idea, or is it a solution in need of a problem?

Bank Security

Having found by coincidence a (minor, perhaps exploitable as part of a more-complex attack) security problem with the website of a major high street bank, one would think it would be easier than it evidently is to get it reported and fixed. Several phone calls over a couple of days, and the threat of making a complaint about a representative if they didn’t escalate me to somebody who’d actually understand what I was explaining, I’ve finally managed to get the message through to somebody. How hard was that? Too hard.

If this still doesn’t work, what’s the next step? I’m thinking (1) change banks; (2) explain why to the bank; (3) explain why to the world. Seriously, I expect better from the people looking after my money.

And on that note: time for bed.

Edit: Meanwhile, we see that the PlayStation Network hack may have resulted in the theft of personal information from users’ accounts. While most of the media seems to be up in arms about the fact that this might have included credit card information, I’m most pissed-off about the fact that it might have included unencrypted passwords. Passwords should be stored using irreversible encryption: there’s no legitimate excuse not to do this, these days (the short version for the uninterested: there is a technique which can be used to store passwords encrypted in a pretty-much irreversible format, even if the hacker steals your entire computer: it’s very easy to do, protects against all kinds of collateral damage risks, and Sony evidently don’t do it). If any of Sony’s users use the same password for their email account, social network accounts, online banks, etc. (and many of them will, despite strong recommendations to the contrary), the hackers are probably already getting started with social hacking attempts against their friends, identity theft attacks, etc. Sony: you are a fail.

Ruth wrote:

We are in the process of ordering a new computer. Most of the bits are coming from Scan. Now, their range is lovely, and their postage policy is reasonably sensible, but they have a dumb policy on debit cards.

If you pay with a debit card (instead of a credit card), you can only have the goods delivered to your registered home address. Now, that might seem ok, because where else are you going to want stuff delivered, right? Wrong. You might want thehardware delivered to your place of work because you’re never home during the day. It might be something your buying for a technologically inept relative and you might want it to go to their home, not yours.

Or, like me, you might be a lazy student who uses their mother’s address in far-off North Yorkshire as their home address so they don’t have to change it twice a year.

Things like this which penalise people who don’t use credit cards make me cross. If anyone knows otherwise, please say, but to me it seems that it’s all just a big conspiracy by the banks to make us all use a really, really inferior product.

Anyway. Out of a desire not to have the computer bits go to Yorkshire, we’ve given the money to Dan who’ll be placing the prder with his credit card and getting it sent to our new house in PJM.
On the subject of the post, my mother called me last night to ask for my new address so she could re-direct some letters from the university. So the items in question will have travelled from the campus to PJM (that is, over the road) via North Yorkshire. How very, very silly.

Anyhoo folks, I’ve got to go to work. Oh yeah, and house-warming party tonight, number 72 PJM. Punch and cake provided; if you want anything else, bring it with you.

Forcing people to have deliveries sent to their registered address cuts down on card fraud, which is moderately freqent at mail order computer hardware stores on account of the high value, discreetness, and availability of the goods. It’s not possible to accurately perform such checks on credit cards, but it’s easy to with debit cards.

Many banks give special dispensation on their student accounts; allowing them to – for example – submit two addresses which they will automatically switch between throughout the year – or allow two registered addresses to function for card checks (while still delivering the statements to one). Ask your bank if they can do this, and, if they can’t, write a letter to inform them that there are banks that can. If you’re not willing to let your feet do the talking, there’s no way to let these large organisations listen to you.

There’s no reason not to own a credit card unless you feel you cannot trust yourself to do so – or the banks won’t give you one! For many such cards, there is no interest if you pay them off immediately each month (which can be automated thanks to wonderful schemes like Direct Debit): this increases the flexibility of your purchasing power (particularly when purchasing from overseas) without costing you a penny. On a side note, owning one that you only ever use in this fashion increases your credit rating (which is checked when buying a contract mobile phone, getting a mortgage, applying for credit on a car, or whatever). Just for examples’ sake; if you owned an unused credit card, you could have ordered these computer parts and – odds are – immediately transferred the money from the bank account to the card, thereby giving you the bits sooner.

All of that said, I think I’ve quite aptly (and almost entirely) undermined the sense in preventing expensive goods being delivered only to the registered cardholder’s address, because as we’ve just seen there’s always a way to circumvent such checks by routing the money other ways: this leaves a longer paper-trail (banks and credit companies are, by law, required to keep better records for longer than companies that happen to process card transactions), but is otherwise a sensible way to commit fraud without triggering the little alarm bells that debit cards have hanging from them. So yeah; perhaps Scan should be a little less draconian.

Now Chip-And-PIN in the UK: there’s a flawed, insecure, badly-implemented system.