A review of the Curve debit card

Somehow, I end up spending a significant amount of my time thinking, testing and playing with financial services, both old school banks and fintech startups.

One of the most recent ones I have been playing with is Curve. The premise of the service is to allow you to use a single card for all transactions, having the ability to then charge any card underneath it as it is convenient. This was a curious enough idea, so I asked the friend who was telling me about it to give me his referral code to sign up. If you want to sign up, my code is BG2G3.

Signing up and getting the card is quite easy, even though they have (or had when I signed up) a “waitlist” — so after you sign up it takes a few days for you to be able to actually order the card and get it in your hands. They suggest you to make other people sign up for it as well to lower the time in the waitlist, but that didn’t seem to be a requirement for me. The card arrived, to my recalling, no more than two days after they said they shipped it, probably because it was coming from London itself, and that’s all you need to receive.

So how does this all work? You need to connect your existing cards to Curve, and verify them to be able to charge them — verification can be either through a 3Dsecure/Verified by Visa login, or through the usual charge-code-reverse dance that Google, PayPal and the others all use. Once you connect the cards, and select the currently-charged card, you can start using the Curve card to pay, and it acts as a “proxy” for the other card, charging it for the same amount, with some caveats.

The main advantage that my friend suggested for this set up is that you if you have a corporate card (I do), you can add that one to Curve too, and rely on that to not have to do the payback process at work if you make a mistake paying for something. As this happened to me a few times before, mostly out of selecting the wrong payment profile in apps such as Uber or Hailo, or going over the daily allowance for meals as I changed plans, it sounded interesting enough. This can work both by making sure to select the corporate card before making the purchase (for instance by defaulting to it during a work trip), or by “turning back time” on an already charged transaction. Cool.

I also had a hope that the card could be attached to Google Pay, but that’s not the case. Nor they implement their own NFC payment application, which is a bit disappointing.

Beside the “turn back time” feature, the app also has some additional features, such as the integration with the accounting software Xero, including the ability to attach a receipt image to the expense (if this was present for Concur, I’d be a real believer, but until then it’s not really that useful to me), and to receive email “receipts” (more like credit card slips) for purchases made to a certain card (not sure why that’s not just a global, but meh).

Not much else is available in the app to make it particularly useful or interesting to me, honestly. There’s some category system for expenses, very similar to the one for Revolut, but that’s about it.

On the more practical side of things, Curve does not apply any surcharges as long as the transaction is in the same currency as the card, and that includes the transactions in which you turned back time. Which is handy if you don’t know what the currency you’ll be charged in will be in, though that does not really happen often.

What I found particularly useful for this is that the card itself look like a proper “British” card — with my apartment as the verified address on it. But then I can charge one of my cards in Euro, US Dollars, or Revolut itself… although I could just charge Revolut in those cases. The main difference between the two approach is that I can put the Euro purchases onto an Euro credit card, instead of a debit one… except that the only Euro credit card I’m left also has my apartment as its verifiable billing address, so… I’d say I’m not the target audience for this feature.

For “foreign transactions” (that is, where the charged currency and the card currency disagree), Curve charges a 1% foreign transaction fee. This is pointless for me thanks to Revolut, but it still is convenient if you only have accounts with traditional banks, particularly in the UK where most banks apply a 3% foreign transaction fee instead.

In addition to the free card, they also offer a £50 (a year, I guess — it’s not clear!) “black” card that offers 1% cashback at selected retailers. You can actually get 90 days cashback for three retailers of your choice on the free card as well, but to be honest, American Express is much more widely accepted in chains, and its rewards are better. I ended up choosing to do the cashback with TfL, Costa (because they don’t take Amex contactless anyway), and Sainsbury’s just to select something I use.

In all of this, I have to say I fail to see where the business makes money. Okay, financial services are not my area of expertise, but if you’re just proxying payments, without even taking deposits (the way Revolut does), and not charging additional foreign transaction fees, and even giving cashback… where’s the profit?

I guess there is some money to be made by profiling users and selling the data to advertisers — but between GDPR and the fact that most consumers don’t like the idea of being made into products with no “kick back”. I guess if it was me I would be charging 1% on the “turn back time” feature, but that might make moot the whole point of the service. I don’t know.

At the end of the day, I’m also not sure how useful this card is going to be for me, on the day to day. The ability to have a single entry in those systems that are used “promiscuously” for business and personal usage sounds good, but even in that case, it means ignoring the advantages of having a credit card, and particularly a rewards card like my Amex. So, yeah, don’t really see much use for it myself.

It also complicates things when it comes to risk engines for fraud protection: your actual bank will see all the transactions as coming from a single vendor, with the minimum amount of information attached to it. This will likely defeat all the fraud checks by the bank, and will likely rely on Curve’s implementation of fraud checks — which I have no idea how they work, since I have not yet managed to catch them.

Also as far as I could tell, Curve (like Revolut) does not implement 3DSecure (the “second factor” authentication used by a number of merchants to validate e-commerce transactions), making it less secure than any of the other cards I have — a cloned/stolen card can only be disabled after the fact, and replaced. Revolut at least allows me to separate the physical card from my e-commerce transactions, which is neat (and now even supports one time credit card numbers).

There is also another thing that is worth considering, that shows the different point of views (and threat models) of the two services: Curve becomes your single card (single point of failure, too) for all your activities: it makes your life easy by making sure you only ever need to use one card, even if you have multiple bank accounts in multiple countries, and you can switch between them at the tap of a finger. Revolut on the other hand allows you to give each merchant its own credit card number (Premium accounts get unlimited virtual cards) — or even have “burner” cards that change numbers after use.

All in all, I guess it depends what you want to achieve. Between the two, I think I’ll vastly stick to Revolut, and my usage of Curve will taper off once the 90 days cashback offer is completed — although it’s still nice to have for a few websites that gave me trouble with Revolut, as long as I’m charging my Revolut account again, and the charge is in Sterling.

If you do want to sign up, feel free to use BG2G3 as the referral code, it would give a £5 credit for both you and me, under circumstances that are not quite clear to me, but who knows.

The dot-EU kerfuffle — or how EURid is messing with their own best supporters

TL;DR summary: be very careful if you use a .eu domain as your point of contact for anything. If you’re thinking of registering a .eu domain to use as your primary domain, just don’t.

I have forecasted a rant when I pointed out I changed domain with my move to WordPress.

I have registered flameeyes.eu nearly ten years ago, part of the reason was because flameeyes.com was (at the time) parked to a domain squatter, and part because I have been a strong supported of the European Union.

In those ten years I started using the domain not just for my website, but as my primary contact email. It’s listed as my contact address everywhere, I have all kind of financial, commercial and personal services attached to that email. It’s effectively impossible for me to ever detangle from it, even if I spend the next four weeks doing nothing but amending registrations — some services just don’t allow you to ever change email address; many requires you to contact support and spend time talking with a person to get the email updated on the account.

And now, because I moved to the United Kingdom, which decided to leave the Union, the Commission threatens to prevent me from keeping my domain. It may sound obvious, since EURid says

A website with a .eu or .ею domain name extension tells your customers that you are a legal entity based in the EU, Iceland, Liechtenstein or Norway and are therefore, subject to EU law and other relevant trading standards.

But at the same time it now provides a terrible collapse of two worlds: technical and political. The idea that you any entity in control of a .eu domain is by requirement operating under EU law sounds good on paper… until you come to this corner case where a country leaves the Union — and now either you water down this promise, eroding trust in the domain by not upholding this law domain, or you end up with domain takeover, eroding trust in the domain on technical merit.

Most of the important details for this are already explained in a seemingly unrelated blog post by Hanno Böck: Abandoned Domain Takeover as a Web Security Risk. If EURid will forbid renewal of .eu domains for entities that are no longer considered part of the EU, a whole lot of domains will effectively be “up for grabs”. Some may currently be used as CDN aliases, and be used to load resources on other websites; those would be the worst, as they would allow the controller of the domains to inject content in other sites that should otherwise be secure.

But even more important for companies that used their .eu domain as their primary point of contact: think of any PO, or invoice, or request for information, that would be sent to a company email address — and now think of a malicious actor getting access to those communications! This is not just the risk that me (and any other European supporter who happened to live in the UK, I’m sure I’m not alone) as a single individual have — it’s a possibly unlimited amount of scams that people would be subjected to, as it would be trivial to pass for a company, once their domain is taken over!

As you can see from the title, I think this particular move is also going to hit the European supporters the most. Not just because of those individuals (like me!) who wanted to signal how they feel part of something bigger than their country of birth, but also because I expect a number of UK companies used .eu domain specifically to declare themselves open to European customers — as otherwise, between pricing in Sterling, and a .co.uk domain, it would always feel like buying “foreign goods”. Now those companies, that believed in Europe, find themselves in the weakest of positions.

Speaking of individuals, when I read the news I had a double-take, and had to check the rules for .eu domains again. At first I assumed that something was clearly wrong: I’m a European Union citizen, surely I will be able to keep my domain, no matter where I live! Unfortunately, that’s not the case:

In this first step the Registrant must verify whether it meets the General
Eligibility Criteria, whereby it must be:
(i) an undertaking having its registered office, central administration or
principal place of business within the European Union, Norway, Iceland
or Liechtenstein, or
(ii) an organisation established within the European Union, Norway, Iceland
or Liechtenstein without prejudice to the application of national law, or
(iii) a natural person resident within the European Union, Norway, Iceland or
Liechtenstein.

If you are a European Union citizen, but you don’t want your digital life to ever be held hostage by the Commission or your country’s government playing games with it, do not use a .eu domain. Simple as that. EURid does not care about the well-being of their registrants.

If you’re a European company, do think twice on whether you want to risk that a change in government for the country you’re registered in would lead you to open both yourself, your suppliers and your customers into the a wild west of overtaken domains.

Effectively, what EURid has signalled with this is that they care so little about the technical hurdles of their customers, that I would suggest against ever relying on a .eu domain for anyone at all. Register it as a defense against scammers, but don’t do business on it, as it’s less stable than certain microstate domains, or even the more trendy and modern gTLDs.

I’ll call this a self-goal. I still trust the European Union, and the Commission, to have the interests of the many in their mind. But the way they tried to apply a legislative domain to the .eu TLD was brittle at best to begin with, and now there’s no way out of here that does not ruin someone’s day, and erode the trust in that very same domain.

It’s also important to note that most of the bigger companies, those that I hear a lot of European politicians complain about, would have no problem with something like this: just create a fully-own subsidiary somewhere in Europe, say for instance Slovakia, and have it hold onto the domain. And have it just forward onto a gTLD to do business on, so you don’t even give the impression of counting on that layer of legislative trust.

Given the scary damage that would be caused by losing control over my email address of ten years, I’m honestly considering looking for a similar loophole. The cost of establishing an LLC in another country, firmly within EU boundaries, is not pocket money, but it’s still chump change compared to the amount of damage (financial, reputation, relationships, etc) that it would be a good investment.

WordPress, really?

If you’re reading this blog post, particularly directly on my website, you probably noticed that it’s running on WordPress and that it’s on a new domain, no longer referencing my pride in Europe, after ten years of using it as my domain. Wow that’s a long time!

I had two reasons for the domain change: the first is that I didn’t want to keep the full chain of redirects of extremely old link onto whichever new blogging platform I would select. And the second is it that it made it significantly easier to set up a WordPress.com copy of the blog while I tweaked and set it up, rather than messing up with the domain at once. The second one will come with a separate rant very soon, but it’s related to the worrying statement from the European Commission regarding the usage of dot-EU domains in the future. But as I said, that’s a separate rant.

I have had a few people surprised when I was talking over Twitter about the issues I faced on the migration. I want to give some more context on why I went this way.

As you remember, last year I complained about Hugo – to the point that a lot of the referrers to this blog are still coming from the Hacker News thread about that – and I started looking for alternatives. And when I looked at WordPress I found that setting it up properly would take me forever, so I kept my mouth shut and doubled-down on Hugo.

Except, because of the way it is set up, it meant not having an easy way to write blog posts, or correct blog posts, from a computer that is not my normal Linux laptop with the SSH token and everything else. Which was too much of a pain to keep working with. While Hector and others suggested flows that involved GIT-based web editors, it all felt too Rube Goldberg to me… and since moving to London my time is significantly limited compared to before, so I either spend time on setting everything up, or I can work on writing more content, which can hopefully be more useful.

I ended up deciding to pay for the personal tier of WordPress.com services, since I don’t care about monetization of this content, and even the few affiliate links I’ve been using with Amazon are not really that useful at the end of the day, so I gave up on setting up OneLink and the likes here. It also turned out that Amazon’s image-and-text links (which use JavaScript and iframes) are not supported by WordPress.com even with the higher tiers, so those were deleted too.

Nobody seems to have published an easy migration guide from Hugo to WordPress, as most of the search queries produced results for the other way around. I will spend some time later on trying to refine the janky template I used and possibly release it. I also want to release the tool I wrote to “annotate” the generated WRX file with the Disqus archive… oh yes, the new blog has all the comments of the old one, and does not rely on Disqus, as I promised.

On the other hand, there are a few things that did get lost in the transition: while JetPack Plugin gives you the ability to write posts in Markdown (otherwise I wouldn’t have even considered WordPress), it doesn’t seem like the importer knows at all how to import Markdown content. So all the old posts have been pre-rendered — a shame, but honestly that doesn’t happen very often that I need to go through old posts. Particularly now that I merged in the content from all my older blogs into Hugo first, and now this one massive blog.

Hopefully expect more posts from me very soon now, and not just rants (although probably just mostly rants).

And as a closing aside, if you’re curious about the picture in the header, I have once again used one of my own. This one was taken at the maat in Lisbon. The white balance on this shot was totally off, but I liked the result. And if you’re visiting Lisbon and you’re an electronics or industrial geek you definitely have to visit the maat!

Reverse Engineering and Serial Adapter Protocols

In the comments to my latest post on the Silicon Labs CP2110, the first comment got me more than a bit upset because it was effectively trying to mansplain to me how a serial adapter (or more properly an USB-to-UART adapter) works. Then I realized there’s one thing I can do better than complain and that is providing even more information on this for the next person who might need them. Because I wish I knew half of what I know now back when I tried to write the driver for ch314.

So first of all, what are we talking about? UART is a very wide definition for any interface that implements serial communication that can be used to transmit between a host and a device. The word “serial port” probably bring different ideas to mind depending on the background of a given person, whether it is mice and modems connected to PCs, or servers’ serial terminals, or programming interfaces for microcontrollers. For the most part, people in the “consumer world” think of serial as RS-232 but people who have experience with complex automation systems, whether it is home, industrial, or vehicle automation, have RS-485 as their main reference. None of that actually matters, since these standards mostly deal with electrical or mechanical standards.

As physical serial ports on computer stopped appearing many years ago, most of the users moved to USB adapters. These adapters are all different between each other and that’s why there’s around 40KSLOC of serial adapters drivers in the Linux kernel (according to David’s SLOCCount). And that’s without counting the remaining 1.5KSLOC for implementing CDC ACM which is the supposedly-standard approach to serial adapters.

Usually the adapters are placed either directly on the “gadget” that needs to be connected, which expose a USB connector, or on a cable used to connect to it, in which case the device usually has a TRS or similar connectors. The TRS-based serial cables appeared to become more and more popular thanks to osmocom as they are relatively inexpensive to build, both as cables and as connectors onto custom boards.

Serial interface endpoints in operating systems (/dev/tty{S,USB,ACM}* on Linux, COM* on Windows, and so on) do not only transfer data between host and device, but also provides configuration of parameters such as transmission rate and “symbol shape” — you may or may not have heard references to something like “9600n8” which is a common way to express the transmission protocol of a serial interface: 9600 symbols per second (“baud rate”), no parity, 8-bit per symbol. You can call these “out of band” parameters, as they are transmitted to the UART interface, but not to the device itself, and they are the crux of the matter of interacting with these USB-to-UART adapters.

I already wrote notes about USB sniffing, so I won’t go too much into detail there, but most of the time when you’re trying to figure out what the control software sends to a device, you start by taking a USB trace, which gives you a list of USB Request Blocks (effectively, transmission packets), and you get to figure out what’s going on there.

For those devices that use USB-to-UART adapters and actually use the OS-provided serial interface (that is, COM* under Windows, where most of the control software has to run), you could use specialised software to only intercept the communication on that interface… but I don’t know of any such modern software, while there are at least a few well-defined interface to intercept USB communication. And that would not work for software that access the USB adapter directly from userspace, which is always the case for Silicon Labs CP2110, but is also the case for some of the FTDI devices.

To be fair, for those devices that use TRS, I actually have considered just intercepting the serial protocol using the Saleae Logic Pro, but beside being overkill, it’s actually just a tiny fraction of the devices that can be intercepted that way — as the more modern ones just include the USB-to-UART chip straight onto the device, which is also the case for the meter using the CP2110 I referenced earlier.

Within the request blocks you’ll have not just the serial communication, but also all the related out-of-band information, which is usually terminated on the adapter/controller rather than being forwarded onto the device. The amount of information changes widely between adapters. Out of those I have had direct experience, I found one (TI3420) that requires a full firmware upload before it would start working, which means recording everything from the moment you plug in the device provides a lot more noise than you would expect. But most of those I dealt with had very simple interfaces, using Control transfers for out-of-band configuration, and Bulk or Interrupt1 transfers for transmitting the actual serial interface.

With these simpler interfaces, my “analysis” scripts (if you allow me the term, I don’t think they are that complicated) can produce a “chatter” file quite easily by ignoring the whole out of band configuration. Then I can analyse those chatter files to figure out the device’s actual protocol, and for the most part it’s a matter of trying between one and five combinations of transmission protocol to figure out the right one to speak to the device — in glucometerutils I have two drivers using 9600n8 and two drivers using 38400n8. In some cases, such as the TI3420 one, I actually had to figure out the configuration packet (thanks to the Linux kernel driver and the datasheet) to figure out that it was using 19200n8 instead.

But again, for those, the “decoding” is just a matter to filtering away part of the transmission to keep the useful parts. For others it’s not as easy.

0029 <<<< 00000000: 30 12                                             0.

0031 <<<< 00000000: 05 00                                             ..

0033 <<<< 00000000: 2A 03                                             *.

0035 <<<< 00000000: 42 00                                             B.

0037 <<<< 00000000: 61 00                                             a.

0039 <<<< 00000000: 79 00                                             y.

0041 <<<< 00000000: 65 00                                             e.

0043 <<<< 00000000: 72 00                                             r.

This is an excerpt from the chatter file of a session with my Contour glucometer. What happens here is that instead of buffering the transmission and sending a single request block with a whole string, the adapter (FTDI FT232RL) sends short burts, probably to reduce latency and keep a more accurate serial protocol (which is important for device that need accurate timing, for instance some in-chip programming interfaces). This would be also easy to recompose, except it also comes with

0927 <<<< 00000000: 01 60                                             .`

0929 <<<< 00000000: 01 60                                             .`

0931 <<<< 00000000: 01 60                                             .`

which I’m somehow sceptical they come from the device itself. I have not paid enough attention yet to figure out from the kernel driver whether this data is marked as coming from the device or is some kind of keepalive or synchronisation primitive of the adapter.

In the case of the CP2110, the first session I captured starts with:

0003 <<<< 00000000: 46 0A 02                                          F..

0004 >>>> 00000000: 41 01                                             A.

0006 >>>> 00000000: 50 00 00 4B 00 00 00 03  00                       P..K.....

0008 >>>> 00000000: 01 51                                             .Q

0010 >>>> 00000000: 01 22                                             ."

0012 >>>> 00000000: 01 00                                             ..

0014 >>>> 00000000: 01 00                                             ..

0016 >>>> 00000000: 01 00                                             ..

0018 >>>> 00000000: 01 00                                             ..

and I can definitely tell you that the first three URBs are not sent to the device at all. That’s because HID (the higher-level protocol that CP2110 uses on top of USB) uses the first byte of the block to identify the “report” it sends or receives. Checking these against AN434 give me a hint of what’s going on:

  • report 0x46 is “Get Version Information” — CP2110 always returns 0x0A as first byte, followed by a device version, which is unspecified; probably only used to confirm that the device is right, and possibly debugging purposes;
  • report 0x41 is “Get/Set UART Enabled” — 0x01 just means “turn on the UART”;
  • report 0x50 is “Get/Set UART Config” — and this is a bit more complex to parse: the first four bytes (0x00004b00) define the baud rate, which is 19200 symbols per second; then follows one byte for parity (0x00, no parity), one for flow control (0x00, no flow control), one for the number of data bits (0x03, 8-bit per symbol), and finally one for the stop bit (0x00, short stop bit); that’s a long way to say that this is configured as 19200n8.
  • report 0x01 is the actual data transfer, which means the transmission to the device starts with 0x51 0x22 0x00 0x00 0x00 0x00.

This means that I need a smarter analysis script that understands this protocol (which may be as simple as just ignoring anything that does not use report 0x01) to figure out what the control software is sending.

And at the same time, it needs code to know how “talk serial” to this device. Usually the out-of-bad configuration is done by a kernel driver: you ioctl() the serial device to the transmission protocol you need, the driver sends the right request block to the USB endpoint. But in the case of the CP2110 device, there’s no kernel driver implementing this, at least per Silicon Labs design: since HID devices are usually exposed to userland, and in particular to non-privileged applications, sending and receiving the reports can be done directly from the apps. So indeed there is no COM* device exposed on Windows, even with the drivers installed.

Could someone (me?) write a Linux kernel driver that expose CP2110 as a serial, rather than HID, device? Sure. It would require fiddling around with the HID subsystem a bit to have it ignore the original device, and that means it’ll probably break any application built with Silicon Labs’ own development kit, unless someone has a suggestion on how to have both interfaces available at the same time, while it would allow accessing those devices without special userland code. But I think I’ll stick with the idea of providing a Free and Open Source implementation of the protocol, for Python. And maybe add support for it to pyserial to make it easier for me to use it.

  1. All these terms make more sense if you have at least a bit of knowledge of USB works behind the scene, but I don’t want to delve too much into that.
    [return]

Yak Shaving: Silicon Labs CP2110 and Linux

One of my favourite passtimes in the past years has been reverse engineering glucometers for the sake of writing an utility package to export data to it. Sometimes, in the quest of just getting data out of a meter I end up embarking in yak shaves that are particularly bothersome, as they are useful only for me and no one else.

One of these yak shaves might be more useful to others, but it will have to be seen. I got my hands on a new meter, which I will review later on. This meter has software for Windows to download the readings, so it’s a good target for reverse engineering. What surprised me, though, was that once I connected the device to my Linux laptop first, it came up as an HID device, described as an “USB HID to UART adapter”: the device uses a CP2110 adapter chip by Silicon Labs, and it’s the first time I saw this particular chip (or even class of chip) in my life.

Effectively, this device piggybacks the HID interface, which allows vendor-specified protocols to be implemented in user space without needing in-kernel drivers. I’m not sure if I should be impressed by the cleverness or disgusted by the workaround. In either case, it means that you end up with a stacked protocol design: the glucometer protocol itself is serial-based, implemented on top of a serial-like software interface, which converts it to the CP2110 protocol, which is encapsulated into HID packets, which are then sent over USB…

The good thing is that, as the datasheet reports, the protocol is available: “Open access to interface specification”. And indeed in the download page for the device, there’s a big archive of just-about-everything, including a number of precompiled binary libraries and a bunch of documents, among which figures AN434, which describe the full interface of the device. Source code is also available, but having spot checked it, it appears it has no license specification and as such is to be considered proprietary, and possibly virulent.

So now I’m warming up to the idea of doing a bit more of yak shaving and for once trying not to just help myself. I need to understand this protocol for two purposes: one is obviously having the ability to communicate with the meter that uses that chip; the other is being able to understand what the software is telling the device and vice-versa.

This means I need to have generators for the host side, but parsers for both. Luckily, construct should make that part relatively painless, and make it very easy to write (if not maintain, given the amount of API breakages) such a parser/generator library. And of course this has to be in Python because that’s the language my utility is written in.

The other thing that I realized as I was toying with the idea of writing this is that, done right, it can be used together with facedancer, to implement the gadget side purely in Python. Which sounds like a fun project for those of us into that kind of thing.

But since this time this is going to be something more widely useful, and not restricted to my glucometer work, I’m now looking to release this using a different process, as that would allow me to respond to issues and codereviews from my office as well as during the (relatively little) spare time I have at home. So expect this to take quite a bit longer to be released.

At the end of the day, what I hope to have is an Apache 2 licensed Python library that can parse both host-to-controller and controller-to-host packets, and also implement it well enough on the client side (based on the hidapi library, likely) so that I can just import the module and use it for a new driver. Bonus points if I can sue this to implement a test fake framework to implement the tests for the glucometer.

In all of this, I want to make sure to thank Silicon Labs for releasing the specification of the protocol. It’s not always that you can just google up the device name to find the relevant protocol documentation, and even when you do it’s hard to figure out if it’s enough to implement a driver. The fact that this is possible surprised me pleasantly. On the other hand I wish they actually released their code with a license attached, and possibly a widely-usable one such as MIT or Apache 2, to allow users to use the code directly. But I can see why that wouldn’t be particularly high in their requirements.

Let’s just hope this time around I can do something for even more people.

Fantasyland: in the world of IPv6 only networks

It seems to be the time of the year when geeks think that IPv6 is perfect, ready to be used, and the best thing after sliced bread (or canned energy drinks). Over on Twitter, someone pointed out to me that FontAwesome (which is used by the Hugo theme I’m using) is not accessible over an IPv6-only network, and as such the design of the site is broken. I’ll leave aside my comments on FontAwesome because they are not relevant to the rant at hand.

You may remember I called IPv6-only networks unrealistic two years ago, and I called IPv6 itself a geeks’ wet dream last year. You should then not be surprised to find me calling this Fantasyland an year later.

First of all, I want to make perfectly clear that I’m not advocating that IPv6 deployment should stop or slow down. I really wish it would be actually faster, for purely selfish reasons I’ll get to later. Unfortunately I had to take a setback when I moved to London, as Hyperoptic does not have IPv6 deployment, at least in my building, yet. But they provide a great service, for a reasonable price, so I have no intention to switch to something like A&A just to get a good IPv6 right now.

$ host hyperoptic.com
hyperoptic.com has address 52.210.255.19
hyperoptic.com has address 52.213.148.25
hyperoptic.com mail is handled by 0 hyperoptic-com.mail.eo.outlook.com.

$ host www.hyperoptic.com
www.hyperoptic.com has address 52.210.255.19
www.hyperoptic.com has address 52.213.148.25

$ host www.virginmedia.com
www.virginmedia.com has address 213.105.9.24

$ host www.bt.co.uk
www.bt.co.uk is an alias for www.bt.com.
www.bt.com has address 193.113.9.162
Host www.bt.com not found: 2(SERVFAIL)

$ host www.sky.com
www.sky.com is an alias for www.sky.com.edgekey.net.
www.sky.com.edgekey.net is an alias for e1264.g.akamaiedge.net.
e1264.g.akamaiedge.net has address 23.214.120.203

$ host www.aaisp.net.uk
www.aaisp.net.uk is an alias for www.aa.net.uk.
www.aa.net.uk has address 81.187.30.68
www.aa.net.uk has address 81.187.30.65
www.aa.net.uk has IPv6 address 2001:8b0:0:30::65
www.aa.net.uk has IPv6 address 2001:8b0:0:30::68

I’ll get back to this later.

IPv6 is great for complex backend systems: each host gets their own uniquely-addressable IP, so you don’t have to bother with jumphosts, proxycommands, and so on so forth. Depending on the complexity of your backend, you can containerize single applications and then have a single address per application. It’s a gorgeous thing. But as you move towards user facing frontends, things get less interesting. You cannot get rid of IPv4 on the serving side of any service, because most of your visitors are likely reaching you over IPv4, and that’s unlikely to change for quite a while longer still.

Of course the IPv4 address exhaustion is a real problem and it’s hitting ISPs all over the world right now. Mobile providers already started deploying networks that only provide users with IPv6 addresses, and then use NAT64 to allow them to connect to the rest of the world. This is not particularly different from using an old-school IPv4 carrier-grade NAT (CGN), which a requirement of DS-Lite, but I’m told it can get better performance and cost less to maintain. It also has the advantage of reducing the number of different network stacks that need to be involved.

And in general, having to deal with CGN and NAT64 add extra work, latency, and in general bad performance to a network, which is why gamers, as an example, tend to prefer having a single-stack network, one way or the other.

$ host store.steampowered.com
store.steampowered.com has address 23.214.51.115

$ host www.gog.com
www.gog.com is an alias for gog.com.edgekey.net.
gog.com.edgekey.net is an alias for e11072.g.akamaiedge.net.
e11072.g.akamaiedge.net has address 2.19.61.131

$ host my.playstation.com
my.playstation.com is an alias for my.playstation.com.edgekey.net.
my.playstation.com.edgekey.net is an alias for e14413.g.akamaiedge.net.
e14413.g.akamaiedge.net has address 23.214.116.40

$ host www.xbox.com
www.xbox.com is an alias for www.xbox.com.akadns.net.
www.xbox.com.akadns.net is an alias for wildcard.xbox.com.edgekey.net.
wildcard.xbox.com.edgekey.net is an alias for e1822.dspb.akamaiedge.net.
e1822.dspb.akamaiedge.net has address 184.28.57.89
e1822.dspb.akamaiedge.net has IPv6 address 2a02:26f0:a1:29e::71e
e1822.dspb.akamaiedge.net has IPv6 address 2a02:26f0:a1:280::71e

$ host www.origin.com
www.origin.com is an alias for ea7.com.edgekey.net.
ea7.com.edgekey.net is an alias for e4894.e12.akamaiedge.net.
e4894.e12.akamaiedge.net has address 2.16.57.118

But multiple other options started spawning around trying to tackle the address exhaustion problem, faster than the deployment of IPv6 is happening. As I already noted above, backend systems, where the end-to-end is under control of a single entity, are perfect soil for IPv6: there’s no need to allocate real IP addresses to these, even when they have to talk over the proper Internet (with proper encryption and access control, goes without saying). So we won’t see more allocations like Xerox’s or Ford’s of whole /8 for backend systems.

$ host www.xerox.com
www.xerox.com is an alias for www.xerox.com.edgekey.net.
www.xerox.com.edgekey.net is an alias for e1142.b.akamaiedge.net.
e1142.b.akamaiedge.net has address 23.214.97.123

$ host www.ford.com
www.ford.com is an alias for www.ford.com.edgekey.net.
www.ford.com.edgekey.net is an alias for e4213.x.akamaiedge.net.
e4213.x.akamaiedge.net has address 104.123.94.235

$ host www.xkcd.com
www.xkcd.com is an alias for xkcd.com.
xkcd.com has address 151.101.0.67
xkcd.com has address 151.101.64.67
xkcd.com has address 151.101.128.67
xkcd.com has address 151.101.192.67
xkcd.com has IPv6 address 2a04:4e42::67
xkcd.com has IPv6 address 2a04:4e42:200::67
xkcd.com has IPv6 address 2a04:4e42:400::67
xkcd.com has IPv6 address 2a04:4e42:600::67
xkcd.com mail is handled by 10 ASPMX.L.GOOGLE.com.
xkcd.com mail is handled by 20 ALT2.ASPMX.L.GOOGLE.com.
xkcd.com mail is handled by 30 ASPMX3.GOOGLEMAIL.com.
xkcd.com mail is handled by 30 ASPMX5.GOOGLEMAIL.com.
xkcd.com mail is handled by 30 ASPMX4.GOOGLEMAIL.com.
xkcd.com mail is handled by 30 ASPMX2.GOOGLEMAIL.com.
xkcd.com mail is handled by 20 ALT1.ASPMX.L.GOOGLE.com.

Another technique that slowed down the exhaustion is SNI. This TLS feature allows to share the same socket for applications having multiple certificates. Similarly to HTTP virtual hosts, that are now what just about everyone uses, SNI allows the same HTTP server instance to deliver secure connections for multiple websites that do not share their certificate. This may sound totally unrelated to IPv6, but before SNI became widely usable (it’s still not supported by very old Android devices, and Windows XP, but both of those are vastly considered irrelevant in 2018), if you needed to provide different certificates, you needed different sockets, and thus different IP addresses. It would not be uncommon for a company to lease a /28 and point it all at the same frontend system just to deliver per-host certificates — one of my old customers did exactly that, until XP became too old to support, after which they declared it so, and migrated all their webapps behind a single IP address with SNI.

Does this mean we should stop caring about the exhaustion? Of course not! But if you are a small(ish) company and you need to focus your efforts to modernize infrastructure, I would not expect you to focus on IPv6 deployment on the frontends. I would rather hope that you’d prioritize TLS (HTTPS) implementation instead, since I would rather not have malware (including but not limited to “coin” miners), to be executed on my computer while I read the news! And that is not simple either.

$ host www.bbc.co.uk
www.bbc.co.uk is an alias for www.bbc.net.uk.
www.bbc.net.uk has address 212.58.246.94
www.bbc.net.uk has address 212.58.244.70

$ host www.theguardian.com  
www.theguardian.com is an alias for guardian.map.fastly.net.
guardian.map.fastly.net has address 151.101.1.111
guardian.map.fastly.net has address 151.101.65.111
guardian.map.fastly.net has address 151.101.129.111
guardian.map.fastly.net has address 151.101.193.111

$ host www.independent.ie
www.independent.ie has address 54.230.14.45
www.independent.ie has address 54.230.14.191
www.independent.ie has address 54.230.14.196
www.independent.ie has address 54.230.14.112
www.independent.ie has address 54.230.14.173
www.independent.ie has address 54.230.14.224
www.independent.ie has address 54.230.14.242
www.independent.ie has address 54.230.14.38

Okay I know these snippets are getting old and probably beating a dead horse. But what I’m trying to bring home here is that there is very little to gain in supporting IPv6 on frontends today, unless you are an enthusiast or a technology company yourself. I work for a company that believes in it and provides tools, data, and its own services over IPv6. But it’s one company. And as a full disclosure, I have no involvement in this particular field whatsoever.

In all of the examples above, which are of course not complete and not statistically meaningful, you can see that there are a few interesting exceptions. In the gaming world, XBox appears to have IPv6 frontends enabled, which is not surprising when you remember that Microsoft even developed one of the first tunnelling protocols to kickstart adoption of IPv6. And of course XKCD, being ran by a technologist and technology enthusiast couldn’t possibly ignore IPv6, but that’s not what the average user needs from their Internet connection.

Of course, your average user spends a lot of time on platforms created and maintained by technology companies, and Facebook is another big player of the IPv6 landscape, so they have been available over it for a long while — though that’s not the case of Twitter. But at the same time, they need their connection to access their bank…

$ host www.chase.com
www.chase.com is an alias for wwwbcchase.gslb.bankone.com.
wwwbcchase.gslb.bankone.com has address 159.53.42.11

$ host www.ulsterbankanytimebanking.ie
www.ulsterbankanytimebanking.ie has address 155.136.22.57

$ host www.barclays.co.uk
www.barclays.co.uk has address 157.83.96.72

$ host www.tescobank.com
www.tescobank.com has address 107.162.133.159

$ host www.metrobank.co.uk
www.metrobank.co.uk has address 94.136.40.82

$ host www.finecobank.com
www.finecobank.com has address 193.193.183.189

$ host www.unicredit.it
www.unicredit.it is an alias for www.unicredit.it-new.gtm.unicreditgroup.eu.
www.unicredit.it-new.gtm.unicreditgroup.eu has address 213.134.65.14

$ host www.aib.ie
www.aib.ie has address 194.69.198.194

to pay their bills…

$ host www.mybills.ie
www.mybills.ie has address 194.125.152.178

$ host www.airtricity.ie
www.airtricity.ie has address 89.185.129.219

$ host www.bordgaisenergy.ie
www.bordgaisenergy.ie has address 212.78.236.235

$ host www.thameswater.co.uk
www.thameswater.co.uk is an alias for aerotwprd.trafficmanager.net.
aerotwprd.trafficmanager.net is an alias for twsecondary.westeurope.cloudapp.azure.com.
twsecondary.westeurope.cloudapp.azure.com has address 52.174.108.182

$ host www.edfenergy.com
www.edfenergy.com has address 162.13.111.217

$ host www.veritasenergia.it
www.veritasenergia.it is an alias for veritasenergia.it.
veritasenergia.it has address 80.86.159.101
veritasenergia.it mail is handled by 10 mail.ascopiave.it.
veritasenergia.it mail is handled by 30 mail3.ascotlc.it.

$ host www.enel.it
www.enel.it is an alias for bdzkx.x.incapdns.net.
bdzkx.x.incapdns.net has address 149.126.74.63

to do shopping…

$ host www.paypal.com
www.paypal.com is an alias for geo.paypal.com.akadns.net.
geo.paypal.com.akadns.net is an alias for hotspot-www.paypal.com.akadns.net.
hotspot-www.paypal.com.akadns.net is an alias for wlb.paypal.com.akadns.net.
wlb.paypal.com.akadns.net is an alias for www.paypal.com.edgekey.net.
www.paypal.com.edgekey.net is an alias for e3694.a.akamaiedge.net.
e3694.a.akamaiedge.net has address 2.19.62.129

$ host www.amazon.com
www.amazon.com is an alias for www.cdn.amazon.com.
www.cdn.amazon.com is an alias for d3ag4hukkh62yn.cloudfront.net.
d3ag4hukkh62yn.cloudfront.net has address 54.230.93.25

$ host www.ebay.com 
www.ebay.com is an alias for slot9428.ebay.com.edgekey.net.
slot9428.ebay.com.edgekey.net is an alias for e9428.b.akamaiedge.net.
e9428.b.akamaiedge.net has address 23.195.141.13

$ host www.marksandspencer.com
www.marksandspencer.com is an alias for prod.mands.com.edgekey.net.
prod.mands.com.edgekey.net is an alias for e2341.x.akamaiedge.net.
e2341.x.akamaiedge.net has address 23.43.77.99

$ host www.tesco.com
www.tesco.com is an alias for www.tesco.com.edgekey.net.
www.tesco.com.edgekey.net is an alias for e2008.x.akamaiedge.net.
e2008.x.akamaiedge.net has address 104.123.91.150

to organize fun with friends…

$ host www.opentable.com
www.opentable.com is an alias for ev-www.opentable.com.edgekey.net.
ev-www.opentable.com.edgekey.net is an alias for e9171.x.akamaiedge.net.
e9171.x.akamaiedge.net has address 84.53.157.26

$ host www.just-eat.co.uk
www.just-eat.co.uk is an alias for 72urm.x.incapdns.net.
72urm.x.incapdns.net has address 149.126.74.216

$ host www.airbnb.com
www.airbnb.com is an alias for cdx.muscache.com.
cdx.muscache.com is an alias for 2-01-57ab-0001.cdx.cedexis.net.
2-01-57ab-0001.cdx.cedexis.net is an alias for evsan.airbnb.com.edgekey.net.
evsan.airbnb.com.edgekey.net is an alias for e864.b.akamaiedge.net.
e864.b.akamaiedge.net has address 173.222.129.25

$ host www.odeon.co.uk
www.odeon.co.uk has address 194.77.82.23

and so on so forth.

This means that for an average user, an IPv6-only network is not feasible at all, and I think the idea that it’s a concept to validate is dangerous.

What it does not mean, is that we should just ignore IPv6 altogether. Instead we should make sure to prioritize it accordingly. We’re in a 2018 in which IoT devices are vastly insecure, so the idea of having a publicly-addressable IP for each of the devices in your home is not just uninteresting, but actively frightening to me. And for the companies that need the adoption, I would hope that the priority right now would be proper security, instead of adding an extra layer that would create more unknowns in their stack (because, and again it’s worth noting, as I had a discussion about this too, it’s not just the network that needs to support IPv6, it’s the full application!). And if that means that non-performance-critical backends are not going to be available over IPv6 this century, so be it.

One remark that I’m sure is going to arrive from at least a part of the readers of this, is that a significant part of the examples I’m giving here appear to all be hosted on Akamai’s content delivery network which, as we can tell from XBox’s website, supports IPv6 frontends. “It’s just a button to press, and you get IPv6, it’s not difficult, they are slackers!” is the follow up I expect. For anyone who has worked in the field long enough, this would be a facepalm.

The fact that your frontend can receive IPv6 connections does not mean that your backends can cope with it. Whether it is for session validation, for fraud detection, or just market analysis, lots of systems need to be able to tell what IP address a connection was coming from. If your backend can’t cope with IPv6 addresses being used, your experience may vary between being unable to buy services and receiving useless security alerts. It’s a full stack world.

UK Banking, Attempt 3: Tesco Bank (and the Irish credit card)

It feels like most of what I end up writing nowadays is my misadventures across a wide range of financial service companies. But here we go (I promise I’ll go back writing about reverse engineering Really Soon Now™).

The last post on this topic was my rant, about how Fineco lacks some basic tools to be used as sole, or primary bank account in the UK. Hopefully they will address this soon, and a sane bank will be available in this country, but for now I had to find alternatives.

Since the various Fintech companies also don’t provide the features I needed, I found myself having to find a “high street bank”. And since my experience up to this point both with Barclays and NatWest was not particularly positive, I decided to look for a different option. Since I have been a mostly-happy customer of Tesco Bank for nearly four years, I decided to give their UK service a try.

At first it appeared to have an online sign-up flow that looked sweet for this kind of problem… except at the end of it, they told me to wait for them to ask me for paperwork to send them through. Turns out the request was for proof of identity (which needs to be certified) and proof of address (which needs to be in original) — the letter and form I could swear is the same that they sent me when I applied for the Irish credit card, except the information is now correct (in Ireland, the Garda will not certify a passport copy, though it appears the UK police forces would).

Let’s ignore the fact that by mailing me at that address, Tesco Bank provided their own proof of address, and let’s focus instead on the fact that they do not accept online print outs, despite almost every service (and, as I found out now, themselves) defaulting to paperless bills and statements. I actually have had a number of bills being mailed to me, including from Hounslow Council, so I have a wide range of choices of what to provide them, but as it turns out, I like a challenge and having some fun with corner cases (particularly as I already solved the immediate need for a bank account by the time I looked into this, but that’s a story for another day).

Here is a part of the story I have not told yet. When I moved to the UK I expected to have to close every account I had still in Ireland, both because Ulster Bank Private is a bloody expensive service, and because at least in Italy I was told I was not entitled to keep credit cards open after I left the country. So as soon as I was in working order over here, I switched over all the billings to Revolut. Unfortunately I couldn’t do that for at least three services (Online.net, Vodafone Italy and Wind/3 Italy) — in two cases because they insist they do not accept anything but Italian cards, while somehow still accepting Tesco Ireland cards.

While trying to figure out an ad-interim solution I got to find out that Tesco Bank has no problem with me still having the “Irish” credit card, and they even allowed me to change the address (and phone number) on file to my new London one. We had some snag regarding the SEPA direct debit, but once I pointed out that they were suggesting breaching the SEPA directives, all was good and indeed the card is debited to the EUR Fineco account.

This also means i get that card’s statements to my London address. So of course I ended up sending, to Tesco Bank, as proof of address… a Tesco Bank Ireland credit card statement. As a way of saying “Do you feel silly enough, now?” to whoever had to manually verify my address and send the paperwork back to me. Turns out it worked just fine, and I got not even a passive aggressive note about it.

Now let’s put aside the registration and let’s take a look at the services provided. Because if I have to rant, I would like at least to rant with some information to others to make up their own mind.

First off, as I said, the first part of the registration is online, after which they get in touch with you to send them the proofs they need. It’s very nice that during the whole time, they “keep in touch” by SMS: they remind you to send the paperwork back, they tell you that the account was open before you receive the snail mail, and so on.

I got a lot of correspondence from Tesco Bank: in addition to the request of proofs, and the proofs being mailed back, I received a notification about the account being opened, the debit card PIN, and a “temporary access number” to sign up online. The debit card arrived separately and through a signature-required delivery. This is a first for me in the UK, as most other cards just got sent through normal mail — except for Fineco, as they used Fedex, and they let me receive it directly at the office, despite it not being the proof of address I sent them.

Once signing up for the online banking, they ask you for an 8-digits security code, a long(er) password, and a selection of verbal question/answers, that are the usual terrible security (so as usual I’ve answered them at random and noted down what I told them the answers were). They allow you to choose your username, but they suggest it to stay the email address on file.

The login for the first time from a different computer is extremely awkward: it starts with two digits of the security code, followed by a SMS second factor authentication, followed by the password (not a subset thereof, so you can use a password manager easily for this one), all through different forms. The same happens for the Mobile Banking application (which is at least linked directly from their website, and very easy to install). The mobile banking login appears to work fairly reliably (and you’ll see on the next post why I call this out explicitly).

I set up the rent standing order on this account, and it was a straightforward and painless process, which is the same as a one-time transaction, except for saying “I want to repeat this every month” checkbox. All in all, it looks to me like it’s a saner UI than Barclays, and proper enough for the needs I have. I will report back if there is anything particularly different from this that I find over time, of course.

Windows 10: what to do if BitLocker and PIN stop working after update

I don’t really like the idea of having to write about proprietary software here, but I only found terrible alternative suggestions on the eb so I thought I would at least try to write down about it in the hope to avoid people falling for very bad advice.

The problem: after updating my BIOS, BitLocker asks for the key at boot, and PIN login for Windows 10 (Microsoft Account) fails, requiring to log in with the full Microsoft account password. Trying to re-enable the PIN fails with the error message “Sorry, there was a problem signing you in”.

The amount of misleading information I found on the Internet is astonishing, including a phrase from what appeared to be a Microsoft support person, stating «The operating system should always go with the BIOS. If the BIOS is freshly updated, then the OS has to be fresh as well.» Facepalms all over the place.

The solution (for me): go back in the BIOS and re-enable the TPM (“Security Module”).

Some background is needed. The 2017 Gamestation I’m using nowadays is built using a MSI X299 SLI PLUS with a plug-in TPM which is a requirement to use BitLocker (and if you think that makes it very safe, think again).

I had just updated the firmware of the motherboard (that at this point we all still call “BIOS” despite being clearly “UEFI” based), and it turns out that MSI just silently drop most of the customization to the BIOS settings after update. In particular this disabled a few required settings, including the TPM itself (and Secure Boot — I wonder if Matthew Garrett would have some words about the implementation of it in this particular board at this point).

I see reports on this for MSI and Gigabyte boards alike, so I can assume that Gigabyte does the same, and requires re-enabling the TPM in the settings when updating the BIOS version.

I would probably say that the MSI firmware engineering does not quite fully convince me. It’s not just the dropping all the settings on update (which I still find is a bad thing to do for users), but also the fact that one of the settings is explicitly marked as “crypto miner mode” — I’m sure looking forward for the time after the bubble bursts so that we don’t have to pay premium for decent hardware just because someone thinks they can make money from nothing. Oh well.

UK Banking, Fineco is not enough

You may remember that the last time I blogged about UK banking I had just dismissed Barclays in favour of Fineco, the Italian investment bank, branch of UniCredit, This seemed a good move, both because people spoke very good of Fineco in my circles, at least in Italy, and because the sign up flow seemed so good that it sounded like a good idea.

I found out almost right away that something was not quite perfect for the UK market, in particular because there was (and is) no way to set up a standing order, which is the standard way to pay for your rent in the UK (and Ireland, for what it’s worth). But it seemed a minor thing to worry about, as the rest of the features of the bank (ability to spend up to £10k in a single transaction by requesting an explicit lift on the card limits with SMS authentication, just to say one).

Unfortunately, a couple of months later I know for sure it is not possible to use Fineco as a primary account in the UK at all. There are two problems, the first being very much a problem to anyone, and the second being a problem for my situation. I’ll start with the first one: direct debit support.

The direct debit system, for those not used to it in Europe, is one where you give a “debtor” (usually, an utility service, such as your ISP or power company) your account details (Sort Code and Account Number in the case of the UK), and they will tell the bank to give them money at certain time of the month. And it is the way Jeremy Clarkson lost £200, ten years ago. There is a nearly identical system in the rest of the EU, called SEPA Direct Debit (with SDD Core being the more commonly known about, as it deals with B2C, business-to-consumer) debits.

After I opened the Fineco account, I checked on Payments UK’s Sort Code Checker which features were enabled for it (30-02-48) and then, as well as the time of writing, it says «Bacs Direct Debits can be set up on this sort code.» So I had no refrain in closing my Barclays account and moving all the money into the newly created account. All of my utilities were more than happy to do so, except for ThamesWater that refused to let me set up the debit online. Turns out they were the only ones with a clue.

Indeed, when in January the first debit was supposed to land, instead of seeing the debit on the statement, I saw a BACS credit of the same amount. I contacted my ISP (Hyperoptic, with the awesome customer support) to verify if something failed on their side, but they didn’t see anything amiss for them. When even Netflix showed up the same way, and both of the transaction showed up an “entry reversal” of the same amount, I knew something was off with the bank and contacted them, originally to no avail.

Indeed, a few more debits showed up the same way, so I have been waiting for the shoe to drop, which it did at the end of January, when Fineco sent me an email (or actually, a ticket, it even has a ticket number!) telling me that they processed the debits as a one-off, but to cancel them because they won’t do this again. This was professional of them, particularly as this way it does not hit my credit score at all, but it still is a major pain in the neck.

My first hope was to be able to just use Revolut to pay the direct debits, since they are all relatively low amounts, which fit my usual auto top-up strategy. When you look at the Revolut information page with your account details for GBP, the text says explicitly «Use this personal UK current account to get salary and to pay bills», which brought me hope, and indeed the Payment UK’s checker also confirmed that it supposedly accepts Bacs Direct Debit. But when I checked with the in-app chat support, I was told that, no Revolut does not support direct debits, which makes that phrase extremely misleading. At least TransferWise explicitly denies supporting Direct Debit in the sort code checker, kudos to them.

The next problem with Fineco is not actually their fault, but is still due to them not having the “full features” of a UK high street bank. I got contacted by Dexters, the real estate company that among other things manages my apartment and collects my rent. While they told me the money arrived all good when I moved to Fineco (I asked them explicitly), they sent me a scary and threatening email (after failing to reach me on the phone, I was going to be charged excessively high roaming charges to answer an unknown number)… because £12 were missing from my payment. The email exchange wasn’t particularly productive (I sent them a photo of the payment confirmation, they told me «[they] received a large sum of money[sic] however it is £12.00 that is outstanding on the account.» So I called them on Monday, and they managed to confirm that it was actually £6 missing in December, and another £6 missing in January.

Throwing this around with colleague, and then discussing with a more reasonable person from Dexters on the phone, we came to figure out that Barclays (as the bank used by Dexters to receive the rent) is charging them £6 to receive these transfers because they are “international” — despite the fact that they are indeed local, it appears Barclays apply that fee for any transfer received over the SWIFT network rather than through the Faster Payments system used by most of the other UK banks. I didn’t want to keep arguing with Dexters over the fact that it’s their bank charging them the fee, I paid the extra £12, and decided to switch the rent payment over to the new account as well. I really dislike Barclays.

I’ll post later this month on the following attempts with other bank accounts. For now I decided that I’ll keep getting my salary into Fineco, and keep a running balance on the “high street” account for the direct debits, and the rent. Right now for my only GBP credit card (American Express) I still pay the balance off Fineco via debit card payment anyway, because the credit limit they gave me is quite limited for my usual spending, particularly now that I can actually charge that card when booking flights on BA without having to spend extra money in fees.

Designing My Password Manager

So while at the (in my opinion excellent) Enigma, Tavis decided to nerd snipe me into thinking of how would I design a password manager. This because he knows (and disagree with) my present choice of using LastPass as my password manager of choice, despite the existence of a range of opensource password managers.

The main reason why I have discarded the choice of the available password managers is that, in my opinion, they all miss the main point of what a password manager should be: convenient. Password reuse is a problem because it’s more convenient than using dozens, maybe hundreds of different passwords for all the different services. An easy to use password manager is even more convenient than reusing password.

The first problem I found with effectively all of the opensource password managers I know of just use a single file-blob, and leave to you the problem of syncing it. The best I have seen was one software providing integration with Dropbox, Google Drive and ownCloud to sync the blob around, just as long as you don’t make conflicting changes on different devices. To me, the ability to make independent changes to services is actually a big requirement. This means that I would be using a file format that allows encrypting “per row”, both the keys and the values (because you don’t want to leak which accounts the user registered on, if the file is leaked). I would probably gravitate around something like the Bigtable format.

Another problem, which is present in Chrome SmartLock too, is the lack of support for what LastPass call “equivalent domains”. Due to many silly reasons, particularly if you travel a lot or if you live in different countries, you end up collecting a long list of websites using either separate domain names, or at least different TLDs. An example of this is Amazon, that use a constellation of different domains, but all share the same account management (except for Amazon Japan). A sillier example for this are Yelp and TripAdvisor, that decide to change your TLDs depending on the IP address you’re coming from, despite being the kind of services you would use particularly outside your usual country.

Admittedly, as Tavis suggested, these should be solved by the services themselves, using a single host for login/identity management. I do not expect this to happen any time soon. My previous proposal for this was defining equivalence as part as a well known configuration file (together with other improvements to password management). I now have some personal introspection questions about this, because I wonder if there is a privacy risk in sending requests to other domain to validate the reciprocal equivalence configurations. So I think I’ll leave this up for debate for later.

The next design bit is figuring out how should the password generator behave. We already have a number of good password generators of different types, including software implementations of diceware passwords (despite the site repeatedly telling you not to use computer random generators — to add to the inconvenience), and xkcdpass, that generate passwords that are easier to remember or at least to type. I think that a good password manager should allow for more than just the random-bunch-of-characters passwords that LastPass uses.

In particular, for me, I have a few websites for which I use passwords generated by xkcdpass, because I need to actually type in the password, rather than use the password manager autofill capabilities. This is the case of Sony and Nintendo accounts, that need to be typed from consoles, and of Telegram, as I need to type the password on my watch to receive messages there. Unfortunately implementing this is probably going to be an UX nightmare — one of the reason being the ability to select different wordlists. Non-English speakers are likely interested in using their own language for it. Or even the English speakers that are not afraid of other languages, and may decide to throw off a possible attacker anyway.

Ideally, the password generation settings would be stored on a domain-by-domain basis, so that if a certain website only allows numbers in its passcode, or it has a specific character limit, the same setting is used to generated a password if it’s ever breached. This may sound minor, but to me it would be so much more of a time (and frustration) saver, that it would easily become a killer feature.

But all of these idea fall to nothing without good, convenient, and trustworthy client implementations. Right now one of the many weak spots of LastPass is its Chrome extension (and Firefox too). A convenient password manager, though, ought to be able to integrate with the browser and, since it’s 2018 after all, with your phone. Unfortunately, here is where any opensource offering can’t really help as much as we would all like: it still relies (hugely) on trust. As far as I can tell, there is no way to make absolutely certain that the code of a Chrome extension on the Web Store, or of an Android app on either Play Store or F-Droid, corresponds exactly with a certain source distribution.

Don’t get me wrong, this is a real problem right now, with closed source extensions too. You need to trust the extension is not injecting malicious content in your webpage, or exfiltrating data out of your browser session. Earlier this year a widely used Chrome extension was reported as malicious, but it wasn’t until that was identified that it was removed from Chrome’s repository. At least I can have a (maybe underserved) trust in LogMeIn not to intentionally ruin their reputation by pushing actively malicious code to the Store. Would I say the same for a random single developer maintaining their widely used extension?

What this means to me is that building a good replacement for LastPass is not just a technical problem that needs to be solved by actively syncing with cloud storage services… it’s a problem of social trust, and that requires quite a bit of thought from many actors of the market: browser vendors, device manufacturers, and developers, which I’m not sure is currently happening. So I don’t hold my breath, and keep at compromises. I made mine with my threats in mind, you should make yours with what concerns you the most.