Let’s talk about usernames

https://www.b-list.org/weblog/2018/feb/11/usernames/

by acjohnson55 • 8 years ago

900 429 8 years ago

Gracana• 8 years ago

And while I could write this as one of those “falsehoods programmers believe about X” articles, my personal preference is to actually explain why this is trickier than people think, and offer some advice on how to deal with it, rather than just provide mockery with no useful context.

Thank you, so much.

I just wanted to highlight that for anyone who looked at the comments to decide whether or not to read the article.

ch4s3• 8 years ago

Yeah, this is a really good article. I really wish more auth systems made use of the tripartite identity pattern.

mooreds2• 8 years ago

This should be exhibit number one why you should always favor open source libraries rather than writing your own plumbing functionality, especially around authentication and authorization. The onus should be on the developer to explain why the open source library isn't a fit, rather than defaulting to 'roll your own'.

The edge cases discussed don't pop up that often unless you have lots of folks using your software or are really diligent about fuzzing and testing edge cases. If you roll your own, say, username system, you probably aren't going to fall into either of those two cases. Which means you're vulnerable.

devmunchies• 8 years ago

but then again, open source does not mean its good software, obviously. there should be some way quickly check if a library meets security best-practices. like a some sort of "vetted software" reference

always_good5• 8 years ago

Also, using a 3rd party library for something as important as authentication because you don't know how it works doesn't sound much better nor secure.

Like storing sensitive data in the authn's session system because you don't understand encryption vs signing nor how to find out -- maybe it's time to just sit down and credentialize as a craftsman.

The authn/z systems I've used that were the biggest headaches in my life were kitchen sink frameworks trying to generalize over everyone's creature features, and they were often tied to a company/community culture of not-gonna-touch-it that only hurt users and security.

rch2• 8 years ago

Actually, the first step in a lot of Django projects is to rip out the default config and ditch usernames in favor of email addresses for login, and attach some form of unique internal id to the "account" (or whatever billing, social IDs, etc. might be associated with).

yjftsjthsd-h2• 8 years ago

Should that be included by default, then?

pc863• 8 years ago

If you don't fall into any of the affected cases, what exactly is the vulnerability? The security aspect I get, and happen to agree with 100%, but if I roll my own sub-optimal username classification system for my CRUD app that gets 80 users in its entire lifetime, so what? I will have certainly learned a lot more than just typical `npm install usernames`.

gravypod• 8 years ago

Uniqueness is harder than you think

Discord has a very interesting solution to this. They have user names and user ids. User IDs are tied to emails and the user's name seems to just be a random text identity for displaying to users. I assume most of their backend code used a unique, sequential or random, integer ID to identify and talk about users while their frontend just makes the ID to a "user name". As long as you slap account creation behind a verification email and don't mind one user being able to sign up for multiple accounts you side step many of the larger problems that come from choosing user names because, in effect, you are choosing the "Real" username and you can make any guarantees that make writing all of your other software easy.

Klathmon• 8 years ago

Blizzard also uses a style like this. While it's great for some use cases, it really sucks for others.

In Blizzard's implementation, I can't add a friend by just knowing their name, I need their id number as well, and the process for finding it isn't exactly front-and-center.

ulzeraj• 8 years ago

I remember when I’ve switched to bnet ID and my tag became username#1337. People sometimes ask me if I’ve bought the name or something like that.

lbill• 8 years ago

I really like Blizzard's solution : {$Username}#{$number} is very practical! It complicates thing a bit when you want to share your contact info to a friend, or when you try to remember a specific battletag, but it solves the uniqueness problem. And to be honest, on most sites I end up using numbers at the end of my username anyways, such as "Username0037".

sergiotapia• 8 years ago

I don't follow the initial premise.

Well, it’s easy until we start thinking about case. If you’re registered as john_doe, what happens if I register as JOHN_DOE? It’s a different username, but could I cause people to think I’m you? Could I get people to accept friend requests or share sensitive information with me because they don’t realize case matters to a computer?

Just this month we fixed this issue by using a citext column in postgres. So yes, it is easy. Maybe I'm missing an edge case here?

https://www.postgresql.org/docs/9.1/static/citext.html

bdcravens• 8 years ago

I assume that's not a standard datatype in all RDBMSs, and the article seems to focus on Django, so I think the author in speaking about ORMs (of course, you generally can also define custom validations in most ORMs, so even a lower() check would help in many cases)

imron• 8 years ago

The problem is not hard to fix from a technical standpoint, but from a practical standpoint it is impossible to fix due to breaking too many sites that were created without case insensitivity and that likely contain conflicts.

acdha• 8 years ago

It’s easy if you thought about it before you have users; people didn’t and then need to ensure that a fix doesn’t break something.

craigds4• 8 years ago

Yeah. We switched to CITEXT for email addresses after 10k users, and had to go through quite a complex process to merge about 30 user accounts that had signed up duplicate accounts with email addresses varying only in case). It was a major PITA

ubernostrum10• 8 years ago

Good for you!

Now, how did you solve the other problems mentioned?

jarofgreen2• 8 years ago

So citext just compares a lower case value of the string, unless I'm missing something?

If so, the rest of the article covers in great detail all the other edge cases :-)

unethical_ban• 8 years ago

These "battle hardened" articles are fascinating. It is the output of years of experience and learning from real problems. It's building the best practices guides, and building the tools to scan for the edge cases. A great read!

saurik2• 8 years ago

The entire concept of usernames that are unique and permanent is stupid and even "cruel". The reality is that a relatively small handful of privileged early adopters get good usernames that match their identities, and everyone else gets screwed. These identifiers then act like tatoos that you got a long time ago and are stuck with for the rest of your life: people end up reminded every day of a sport they can no longer play due to an injury ("hockeystar") or loves lost ("iheartjessie"), attached to a joke that is no longer funny or to a thought that they found adorable as a 13 year old (when you are legally asked to "choose a username": a modern era coming of age scenario) but which adults find inane, or to a nickname that means something different than you realized to some people and now can't change.

The reality is that there are almost ten billion people on this planet and they live for upwards of a century. You are simply deluding yourself if you think it is reasonable to build a system with unique, permanent usernames. Nothing in the real world works like that, including trademarks. And it just helps enforce the very problem that people try to trust usernames and then get tricked by people who sniped usernames that are tied to other peoples' well-known identities (leading to abused "verified" badge systems and legal challenges and expensive hostage scenarios... it just sucks).

And for what? To make it easier to hand-type a URL? Does anyone even do that? I am super technical and I barely even do that in 2018, as if nothing else there are too many websites in existence to remember all of their one-off URL schemes. Like almost everyone, I either use the site's built-in search feature or I do a search on Google to find people, and let a combination of page rank and personalized results guide me to the right destination. Some web browsers don't even show URLs anymore!

Here is a great example of where it is completely insane: Facebook. There is absolutely no good reason for that website to have usernames for regular users, and they frankly shouldn't have usernames for businesses either. It isn't even clear to me that the app--which most users are using, not the website--even has a way to show people's usernames, which means this is an identifier which somehow everyone knows must be chosen and must be unique and is nigh-unto permanent but which somehow is also simultaneously meaningless but is also a horrible point of contention? What?

I am lucky. I spent a bunch of time in 1994 to select a username, and despite being 13, I was mature enough to come up with something that wouldn't ever come to cause me complex problems. People ask me what it means, and it essentially doesn't mean anything: it has only a positive connotation to me when I hear it, it is entirely neutral, and it had no existing usage I could find. Yet, I also still got screwed, as I am semi-famous, and everyone knows me as this username. I have kids who look up to me enough to want to take my name as a show of support and I have to essentially be the big bad asshole about it because in a world of unique and permanent usernames, people then assume the kid is really me. On the other side, I have been asked to rename myself by moderators of various forums as they couldn't believe the real saurik got an account on their site, and it was "confusing" people.

And so in the end we all have to deal with the worst-case scenario anyway: unless you do nothing but sign up for random sites rumored to be interesting constantly (which I seriously tried to do), you eventually will succumb to needing a way to prove who you are on multiple sites and tie together those identifies. And for most users... as in virtually all "normal users", that moment comes when they are using only two websites, as their username was probably something like jay.freeman.178 as everything that was even remotely interesting to them was taken a decade earlier by literally a different generation of humans, so they let the website automatically generate one.

In a world where everyone is having to solve the worst-case problem anyway, every site should just have numbers as unique identifiers, at most have some kind of trust score for degrees of separation on the site (so you can get a feeling for "is this the saurik that I met?"), and everyone should be trained "names don't matter and if you see someone with that name it doesn't even slightly mean that they are the same person you met last week".

grzm2• 8 years ago

The article does a very intelligent job of disentangling system identifier, login, and display names (and helpfully links to a discussion of the tripartite identity pattern†), which obviates a lot of what you describe here.

† http://habitatchronicles.com/2008/10/the-tripartite-identity...

saurik2• 8 years ago

Yes, but it does not bother to motivate why people should use "tripartite identity" (and even that linked article doesn't really try to make an argument); and then it goes on to talk about why uniqueness is hard from a technical level, leading people to be responding with comments like "I just included a library in my stack or chose the right type for my PostgreSQL column that fully handled the case and Unicode mapping, so this wasn't a big deal".

The real problem is that unique and permanent usernames serve as tatoos (which people later may find to be humiliating or depressing), disadvantage late-comer non-technical users (who will almost never have a good username and almost never will have the same username on two websites), and lead to weird problems with assumptions people make about what usernames even mean (that they are a signal for identity) that are simply not true.

henrikschroder2• 8 years ago

Here is a great example of where it is completely insane: Facebook. There is absolutely no good reason for that website to have usernames for regular users, and they frankly shouldn't have usernames for businesses either.

Uh, Facebook doesn't have usernames, and haven't had usernames for as long as I've been able to be a member.

There's an option to grab a unique identifier for your personal page, so that you become https://www.facebook.com/identifier, but it's completely optional, it's just a vanity thing.

Same for groups, they can grab a unique identifier, or stick to their auto-generated id.

Same for businesses.

kiwijamo• 8 years ago

In Facebook I can go to Settings > General to find an option to create a username. Been like this for as long as I can remember.

gregmac• 8 years ago

I've actually not signed up for services at all because the couple username variants I tried were already registered.

I was also recently annoyed at being forced to switch to a new system for my credit card, and it's a unified system with all their other cards and banking customers, and still uses "username" (instead of email) as a login, so of course my name was taken. I decided to just append some random characters, and then realized I could just generate my entire username and have been doing that since, when I don't care about identifying myself to others. My password manger saves it, so it really doesn't matter to me.

kbenson8• 8 years ago

then realized I could just generate my entire username and have been doing that since, when I don't care about identifying myself to others. My password manger saves it, so it really doesn't matter to me.

Even better, if they have your email and use it for password recovery, you can basically turn it into a two step authentication by not saving the password and using password recovery every new time you need to log in. Though, that can get annoying if their password recovery takes a while to send.

freehunter• 8 years ago

I’m annoyed at banks that require my username to have numbers in it but only let me pick an 8 character password.

reaperducer4• 8 years ago

As banks have merged and eaten each other over the years, I've ended up going from four different website to log into to one website with four different usernames.

There's no way to merge the online accounts, even though the banking accounts are merged and I can see all of the financial information from each no matter which login I use.

kqr2• 8 years ago

And for what? To make it easier to hand-type a URL? Does anyone even do that?

This dilutes your otherwise excellent point. URLs are great when done right and lots of people prefer them to the sites search functionality. But that is entirely orthogonal to identities, which barely ever need to show up in a URL. (Unless treated as permanent and uniquely attached to physical people, which we agree they should not.)

mehrdadn19• 8 years ago

every site should just have numbers as unique identifiers

Do you realize how impractical it is for users to remember these numbers for every site? Until we get to the stage where every non-English-speaking user and their grandma finds a password manager convenient, this proposal won't even pass the laugh test.

mozumder4• 8 years ago

Password managers really do need to be forced on people, not only because of unsafe password issues but because of username issues listed in the OP as well.

Too• 8 years ago

Counter point: My grandma could easily memorize her own phone number - and all her friends phone numbers. ICQ also survived for years with numeric identifiers.

Though yes, i agree that once the nr of accounts start going above 1 or 2 a password manager will be required.

inopinatus5• 8 years ago

Don't underestimate the ability of non-technical people. Issuing membership numbers has been standard organisational practice for centuries and continues to work today for everything from airline loyalty schemes to international sports associations.

Case in point, I operate a service that uses numeric identifiers. Going by the helpdesk queries, our users are more likely to get their email address wrong than their membership number.

kuschku6• 8 years ago

Especially when you want to print this on your business card, or spell it out over the phone, or type it into a friend’s contacts app.

100595964940551841549 isn’t exactly usable for that. Even phone numbers, such as 01573 0677867 are much shorter, and they follow a pattern.

bloak• 8 years ago

The number is not confidential, so people would not have to remember it, nor would they have to use a password manager.

Digits are much easier to spell over the phone than a mixture of letters and digits.

People are used to identifying themselves with a sequence of digits. If you're dealing with the tax office, the water company, the electricity company, or whatever, you get asked for your customer number, your meter number, your reference number, and so on, and usually these consist mostly of digits. Sometimes these identifiers are way too long, or several different identifiers are unnecessarily used, or the same sequence of digits is confusingly referred to by several different names ("customer reference", "account number", whatever), but those are separate problems.

Yizahi3• 8 years ago

That's why we need biometric hardware everywhere and use its data as a login, not as a password. Bio data is mapped onto a long UUID and user just sets whatever username he wants to be displayed. We even have means to smoothly transition from no hardware to 100% coverage - just allow manual UUID input for systems where biometric is unavailable - e.g. you have a pair of face/ID on the phone, fingerprint/ID on laptop and just ID on PC.

lazyjones• 8 years ago

Do you realize how impractical it is for users to remember these numbers for every site?

That's really not an issue. It isn't much easier to remember that I'm "John28161" on a busy site. Websites have been offering "I forgot my username" functionality for ages, so as long as you remember your e-mail address, you're fine. Also, just let users bookmark their personal profile page (foo.site.com/user/83755567565) easily and it's solved even if cookies are deleted. Apps won't have a problem either way.

esturk• 8 years ago

I'll give an example of a permanent username that you can't change: Steam. For obvious reasons, Valve is way too underhanded to do anything about this. Nothing malicious, just inept to try because there's just no competition to.

throwaway2048• 8 years ago

Thats true, but your username is not visible to other users, even for stuff like profile pages.

mehrdadn19• 8 years ago

I'll give an example of a permanent username that you can't change: Steam.

No need to go that far... just look at the URL bar right here. :-)

gaius• 8 years ago

real saurik got an account on their site, and it was "confusing" people.

I have no idea who you are and don’t recognise your username. Was that whole rant just a humblebrag that you’re “internet famous”? Because here at least, no one cares.

crooked-v• 8 years ago

https://en.wikipedia.org/wiki/Jay_Freeman

rahoulb• 8 years ago

I care and on HN there will be a lot of people who do. The wider internet, probably less so.

marklgr• 8 years ago

One can be "semi-famous", as OP said, in small circles, Eg. chess, and you wouldn't recognize his username--but maybe lots of chess players would. I didn't see it as humblebrag anyway, since it was a true part of his points.

fbdjskajxb5• 8 years ago

You don’t have to be mean about it! The world is big enough to fit lots of people like you who have no idea who he is, and also people like me who think “wait, is that the same saurik from...”

Seems like a real anxiety, not just a humblebrag. I’ve felt the same way and my response is to just make up new names all the time.

IncRnd• 8 years ago

Maybe you can ask Mr. Saurik for an iOS 11 Jailbreak.

hrrsn2• 8 years ago

I was lucky enough to get a 3 character Instagram handle back in the day. I get 5+ password resets a day and frequent offers for it - the most I've been offered is $25,000 for it. It's a pain.

kbenson8• 8 years ago

It occurs to me there's probably a whole industry built around snatching up interesting account names for all the new services in the hopes that one might make it big. It's slightly complicated by the fact that different norms develop for different platforms (e.g. @realDonaldTrump on twitter because of what I assume were satire accounts).

There are probably people out there with spreadsheets full of service types, account names and passwords of accounts they control that include all the two letter to four or five letter company names, and many celebrity names, just in the case that someone wants to pay for it. The domain name game, just evolved for the current climate.

I mean, it would take me less than $25k worth of my time to build something to automate this, even if I had to get rotating IPs, mobile accounts, and have mechanical turk to solve CAPTCHAs (although with all those features it might be close), and you were offered that for one account.

konschubert• 8 years ago

If it's such a pain why don't you sell it for 25K

xxs• 8 years ago

Go big, ask ten times more and feel relieved from that pain.

protopeer2• 8 years ago

is your account yielding you more than 25k in discounted cash flow? if not, why not sell?

megous• 8 years ago

In a world where everyone is having to solve the worst-case problem anyway, every site should just have numbers as unique identifiers...

ICQ did that. Though it still led to interesting results, because lower numbers were thought to be more valuable, and people were buying/selling those.

Perhaps a random numbers with the same number of digits or UUIDs may work without such issues. :)

kruczek• 8 years ago

Perhaps a random numbers with the same number of digits or UUIDs may work without such issues. :)

Then people will be buying/selling UUIDS which are easier to pronounce or memorize. People will always consider patterns more valuable.

btschaegg2• 8 years ago

I noticed that in many gaming related systems, this is already kind of the case. Blizzard appends random numbers to the end of each username in order to avoid name clashes, Steam lets you change your displayed username (although your account is still accessed through the old one), and so on.

UUIDs were also my first idea, but I have the feeling that sharing them (i.e. to invite a new friend) would be cumbersome. I wonder if a new system akin to what3words.com could help there.

isostatic3• 8 years ago

I remember my ICQ number, not used since 2001 I remember my compuserve number too -- 101611,1220 - not used since 1996. I remember our first phone number as a kid, 818641, which we changed in the early 90s too. I recall friends numbers too, and a bank account I had from 1993 to 2004.

However my slashdot number, which I've had nearly 20 years, I know nothing more than it begins with 2.

The modern numbers I remember are my mobile phone number, my wife's, and my passport numbers (phone numbers as we've had them over a decade and all of them because I have to write them on forms so much). The only other numbers that spring to mind are my staff number at work (used in various forms, had since 2003) and my bank numbers (needed to log on)

If you use a number a lot, you learn it. If you don't (like usernames which are saved) you forget it. I can barely remember my credit card pin as I use contactless so much, but muscle memory seems to work there.

Fnoord2• 8 years ago

Many people used @hotmail.com addresses back in the days (or other free e-mail providers) to register their ICQ number. Heck, you could even search for people on ICQ who were using @hotmail.com addresses. Eventually, those @hotmail.com addresses expired, and you could reregister them. Once you did that, you could recover the ICQ password, and bingo. The old UINs (what the UUID was called back then) were often not in use anymore (my memory is vague if I ever encountered one in use, I think it happened once and I struck a friendship with the one person who msged me). I traded many of these UINs away to friends. Even told some friends about the trick. I never sold them. Eventually the supply dried up.

The weakness lies partly in ICQ: they allowed to easily find all these people using @hotmail.com e-mail address and even showed this information. Sure, you could disable being part of this feature (IIRC it was called "yellow pages" or something akin to it) but still.

The other part of the weakness is exactly the very issue of domain squatting, username squatting, e-mail squatting or whatever you want to call it. I understand Microsoft wants to save space on their e-mail servers back in the early '00s but: former username should be frozen and their e-mail could be either bounced or silently rejected to /dev/null or whatever's the Windows equiv.

Blizzard's WoW has the rule that you you can only get a username from an inactive account. An inactive account is an account which did not play the previous expansion. That's their compromise. To be fair, it is not like people use WoW usernames for password recovery.

As for using numbers as username: that is what UNIX does under the hood, it is what Facebook does under the hood as well, it is what Blizzard's WoW does under the hood as well, and what T9 converts to as well, and ICQ did as well in contrast to MSN. Turns out people are lousy at remembering a bunch of numbers. So they resort to 26 character system of letters, or 36 character system of letters plus numbers. (Some services are more or less strict.) So, no, using numbers as human-usable UUID is not a solution but using it under the hood is totally OK.

leoc2• 8 years ago

More generally, only very rarely should canonical identifiers for computer use ever be meaningful to humans. The (potential, and conventional and UI-encouraged) meaningfulness and tree structure of the HTTP URL path component has probably contributed seriously to the Web's link-rot. Having a tree-structured, human-readable name at the top of the browser window is great! It just shouldn't be the URL.

jve• 8 years ago

By the way, happy 3000th day on HN :)

tjoff5• 8 years ago

And for what?

So that you can be identified? (I'm not talking identified in a mathematical sense, but in a informal conversational sense (you know, what usernames are actually used for)). The whole point of a username is that it is the most humanly convenient way to represent a user in text in the context of a certain site.

Because the alternative would be to have thirteen saurik in the same thread debating a topic and you would have no way of distinguishing them. Avatars are an attempt to fix that but it sucks and is bloated for many scenarios.

Sites that do allow you to change username break conversations where people refer to each other using the username (stackoverflow comments are a really common and annoying issue)

Yes, it is annoying when you don't get your first pick but it truly is not a big deal and it solves a real problem.

jay.freeman.178 is an excellent username. You are not your username.

laumars4• 8 years ago

People can change their legal names, I see no reason why they shouldn't also be able to change their user names.

The problem with breaking continuity in forums and other similar networks can be mitigated via dynamic user name lookups (eg how Facebook does `@` mentions - however I have also seen some forums do this as well), supporting in line quoting (like how message boards often work), nested replies (HN, reddit, etc). Granted there will still be occasions when references slip through the net but us humans have a remarkable ability to deduce the context of the written word even when it doesn't always read perfectly.

nfc• 8 years ago

I agree with you about the identification part. I was wondering whether we could have a user friendly way to have a system of usernames + "something else" that allowed usernames to not be unique while still solving the identification part.

A possible implementation would be to allow the user to give a "nickname" to add to usernames he wants to identify uniquely that would be visible only for them. For example since I talk now with you I could add to your username "user with whom I discussed identities and usernames" and this (or a short version of it) would be shown next to your username from now on.

A more automated way to do this is to create a unique image for the user based on the content they have posted, when they created their account, not so personal but requires less effort from the user, I'm sure such systems exist in many sites to create avatars. Obviously in this machine learning times we could get to do sth much better.

kemitche• 8 years ago

Because the alternative would be to have thirteen saurik in the same thread debating a topic and you would have no way of distinguishing them.

In the real world, people almost always go by their first name, and we don't have this problem. When two people in a social circle have the same first name, we don't turn and say "well everyone has to use their whole name, always, now." Rather, we adjust our names (usually someone gets a nickname, or goes by their last name).

The steam system allows multiple people to have the same display name and it works just fine. Sure, people can troll with it when they join your tf2 server (and then you kick them off).

The blizzard system also works great. The unique identifier is there, if all other forms of attempting to add a friend fail, but mostly you end up working contextually.

coryfklein2• 8 years ago

My name is Cory. Despite sharing that name with 120k other people in the U.S., occurrences of misidentification due to having the same name as somebody else are very rare and usually often resolved by merely using my last name instead.

If your apps' users report problems with identifying people, just allow users to add more specificity to their username. "People always get me confused with this other user 'chairdude', can I change my display name to 'armchairdude'?"

If thirteen 'saurik's want to have a fun time and create a confusing discussion thread together, so be it.

bringtheaction2• 8 years ago

Facebook [...] nigh-unto permanent

I found a way to change it and it still worked last time I tried.

You must install Facebook Messenger. I am using iOS, don't know if the Android version is the same.

Keep in mind that your old username will no longer lead to your profile once changed. For me this was exactly what I wanted but for some they might want to not change their username after all due to this.

In the Facebook Messenger app, tap your profile picture in the top left corner. This brings you to a screen with the title "me". Right under your picture it will say "username m.me/yourusername" where yourusername is your actual username. Tap on your username and select "edit username".

Once you've changed your username in the Facebook Messenger app your identifier on Facebook itself will change also so now when people go to your Facebook profile on facebook.com in their web browser they will see your new username in the address bar.

Figuring this out was actually very difficult, as most information online claimed that your username could not be changed.

Because it somewhat seems to me that Facebook also don't want people to change usernames I ask that everyone who reads this keep that secret. HN pages usually don't rank highly on Google so mentioning it here shouldn't matter too much.

If any Facebook employees read this, please either

a) Make it easy for others to find out by updating official documentation, or

b) Make it easy to change from the main facebook.com application, or

c) Forget that you saw my comment.

As I'd like to be able to change my username in the future as I have done in the past.

SethKinast• 8 years ago

You should be able to change your username in the desktop site settings: https://www.facebook.com/settings?tab=account&section=userna...

emmelaich• 8 years ago

This was solved within corporations to an extent 50 years ago. Institutions that used IBM mainframes tend to use an id of the form aaann where a is a letter and nn a number. An example is Matthew Garret's id "mjg59". Large corps still use something similar. You can have a separate mail address and aliases but they are not your id.

dingaling2• 8 years ago

Names changed to protect the guilty:

I joined a Big Dinosaur Company early enough that they were still using mainframe RACF as the system-of-record for authentication, flowing downstream to LDAP. So indeed I received, for example, dlg28 as my ID and stem for e-mail address.

However after several years the SoR was migrated to Windows LDAP ( can't remember its brand name ) and it generated 'sensible' IDs for all the newer staff. So someone received JimSmith as ID & e-mail address.

We oldies felt old and uncool! So a project introduced self-selected e-mail aliases for the oldies, which then led to interpersonal conflicts because jsm22 wanted JimSmith@, but the 'new' Jim Smith already had that... But jsm22 felt he had title to it since he had worked there 40 years etc etc So he was given JimBSmith@ which of course led to misdirected e-mail. Hilarity ensued.

I'd rather they had never introduced the long-form IDs at all!

subway• 8 years ago

Being unable to move past an old username without having to give up your history is rather uncomfortable too.

During my freshman year of college a particular sandwich shop hired a spokesperson who shared my first name. One thing led to another, and the name of that shop became a lasting nickname.

Unfortunately that spokesperson turned out to be quite a monster, leaving me in a bit of an awkward position on sites that don't allow username changes.

username223• 8 years ago

Don't worry about it, Jared. No one thinks you're a creep, and if you create a new account, you're only sacrificing internet points, which are worth even less than bitcoin.

aluhut7• 8 years ago

No, the reality is that everybody got used to it and nobody cares. What serious pages are there where you could not just create another account if you start to being ashamed for what you have right now? This is seriously a no-problem and giving people numbers is the worst way you could go from here. We are not some kind of 70s science-fiction robots who would love to be called by numbers....damn sometimes I have the feeling that commentators on here are robots. Please go outside some time and ask real people what they think about the new genius idea that just came into your mind.

laumars4• 8 years ago

I'd prefer user names which were changeable rather than numbers; but lets be honest, a numeric only system isn't without precedence: ICQ.

To be honest, given user names are just an arbitrary reference, you could probably also include phone numbers, IP addresses, social security, national insurance and house numbers into the list of prior art as well.

Not that I'm advocating the use of numbers instead of names. Twitter I think gets it right where they give everyone a number which is fixed but you can assign yourself a name; which can change. Most of the time people choose not to, But the option is still there.

MaxBarraclough• 8 years ago

What serious pages are there where you could not just create another account if you start to being ashamed for what you have right now?

Depends what's associated with the account, no?

If it's something like Steam, your username might be tied to hundreds of dollars of purchases.

If it's Slashdot, you'll lose your sweet low user ID.

If it's StackOverflow, you'll lose your various reputation scores.

Sir_Substance• 8 years ago

This is seriously a no-problem

Most users have at least two email addresses because most of their mail is routed through email addresses like "PartyChick88@hotmail.com" but they don't feel comfortable putting that on job applications and medical forms.

It is a statistical certainty that people have missed job opportunities and subsequently defaulted on mortgages because they sent off a bunch of job applications on their "business" email address and then forgot to check it because they don't use it much.

One of the more common office security failures is to have your email client auto-fill to someones personal account instead of their company-issued account, resulting in sensitive documents leaving the auditable environment of the office email server.

Now for sure, it's not exactly up there with global warming and north korea, but I'm not sure I'd call it a "no-problem". It's a fundamental UX failure that we're only just now starting to see get fixed with email address aliases becoming a more widespread feature, and even that is just a patch. We've all gotten used to it, but that doesn't mean it's not a problem.

Zhyl• 8 years ago

The reality is that usernames are seen as a computery tech internet thing rather than a business thing. Unofficial, maybe even frivolous.

In business you have customer account numbers, bank account numbers, membership numbers, invoice numbers etc. There is no conflation with identity - you are not your account with your bank, gym or stationary supplier. It is only because of internet forums and login usernames that we have even gotten to this state of affairs in the first place.

Usernames (or internet aliases in general) were a routinely mocked part of internet culture by mainstream culture. People these days use services in spite of usernames rather than because of them. The president of the united states has 'real' in front of his name. Think about that. In no other medium do we have people asserting that they are the genuine person they are claiming to be. Its tautological.

Tech-Noir• 8 years ago

names don't matter and if you see someone with that name it doesn't even slightly mean that they are the same person you met last week

If this is your belief why have you stuck to a specific name, to the point of signing up to random sites just to take possession of it?

bryanrasmussen2• 8 years ago

Does Facebook actually have usernames the way other sites have usernames? I'm Bryan Rasmussen on Facebook not rasmussen.bryan127 or something, and if I search for somebody by name they recommend lots of people with that name.

user5994461• 8 years ago

There is a unique username and URL for every profile.

bryanrasmussen2• 8 years ago

about the usernames for businesses I just spent some time being confused today because it turns out there is a Viasat in the nordic area, and I thought it was somehow related to the American Viasat.

eurticket• 8 years ago

So you're saying give young kids funny dumb usernames but once they grow up they have to use their real name online?

lyk• 8 years ago

To solve this problem in part, keybase exists. At its core it's a proof-of-identity service, with some fanciness on the side. Sure it doesn't fix the root of the username issue, but it helps a little bit, while having cool things like kbfs and kbp.

keypress3• 8 years ago

Publicly guessable addresses can still be a pain like sequential numerical ones. https://en.wikipedia.org/wiki/CompuServe#User_IDs_and_e-mail...

keypress3• 8 years ago

We used to laugh at those that chose personalised number plates, and yet there is probably more utility in one of those than a vanity url.

dizzymantle• 8 years ago

TLDR all the way..

Yeah so what’s your alternative again?

neya2• 8 years ago

Hey community, shameless plug: For the purpose mentioned in the article to disallow certain usernames, I created this GitHub Repo sometime back. Feel free to submit a pull request :)

https://github.com/dsignr/disallowed-usernames

flurdy3• 8 years ago

Seems I should add some more to https://github.com/flurdy/bad_usernames :)

neya2• 8 years ago

Nice! Maybe we should merge our efforts.

lettergram• 8 years ago

Django’s auth system doesn’t enforce case-insensitive uniqueness of usernames

Their routing (for URLs) is also not case-insensitve. The whole framework by default is case sensitive. Honestly, kind of annoying.

frankwiles• 8 years ago

Honestly never really thought about it much. Wouldn’t that lead to accidentally duplicate URLs in the eyes of things like PageRank?

ronnier• 8 years ago

No. That’s why you embed a canonical url meta tag.

craigds4• 8 years ago

Why would you need case insensitivity in URLs by default? I can imagine you might in the odd view here and there, though in ten years of django usage I don't think I've needed to do so

collinmanderson• 8 years ago

If you use mysql, a lot of things end up being case-insensitive by default. Not necessarily recommending it though.

Mayzie• 8 years ago

Aside from the authors library, django-registration, what other similar libraries for Python and other languages have taken all or some of this into consideration?

Excellent read by the way. Many things I have never considered or even worried about before.

Alex39175• 8 years ago

If you're going to allow unicode usernames then you should casefold them rather than lowercasing them before normalizing as NFKC.

You should ideally also store a second copy of the username in the original casing and normalized as NFC for display purposes, as some users care a lot about seeing their username exactly as they entered it. (And in fact not allowing this may be seen as culturally insensitive in some cases, much like not supporting unicode.) The same applies to the user's first and last name, which you can store in NFC for display purposes and casefolded into NFKC for string comparison (e.g. search) purposes.

That said, most sites limit usernames to ASCII characters so that they can be (easily) used in URLs. In this case you don't need to casefold or normalize, just converting to lowercase is enough.

ubernostrum10• 8 years ago

If you're going to allow unicode usernames then you should casefold them rather than lowercasing them before normalizing as NFKC.

I wanted to stay out of the Python 2 vs. 3 quagmire in this article, but it's worth knowing that in Python 3.3+, strings have a 'casefold()' method:

https://docs.python.org/3/library/stdtypes.html#str.casefold

Unfortunately, since Python 2 still has around two years of upstream support before EOL, I can't universally recommend people just use 'casefold()', no matter how much I'd like to.

dingo_bat3• 8 years ago

No, really, uniqueness is harder than you think

No it's very simple. Restrict usernames to ascii. Do unicode where it makes sense.

Jaruzel• 8 years ago

Which is great for everyone using the Latin alphabet, but what about Cyrillic and other non western-world based languages?

dingo_bat3• 8 years ago

They can use any username they like, as long as it is in ascii.

badsectoracula3• 8 years ago

They can also use ascii, you do not have to use your real name (in fact i'd recommend to not use your real name - it is really concerning how people lost the will for Internet privacy they had in the 90s) as a username. And even if you really really want, for some reason, you can just romanize it.

anowlcalledjosh• 8 years ago

Would it be ridiculous to suggest that this is no different to requiring all usernames to be composed of CJK characters? That would be inconvenient and exclusive, no?

(also, a nitpick: "just ascii" is still the wrong approach, since you probably don't want people putting BEL or NUL in their usernames)

bradleybuda• 8 years ago

So if you’re enforcing unique email addresses, or using email addresses as a user identifier, you need to be aware of this and you probably need to strip all dot characters from the local-part, along with + and any text after it, before doing your uniqueness check. Currently django-registration doesn’t do this, but I have plans to add it in the 3.x series.

Please don't "normalize" email addresses like this. Not all mail systems are Gmail, and many do treat "john.doe@example.com" and "johndoe@example.com" as different identities. And even if we are talking about Gmail - it's not your identity system's job to deduplicate different logical addresses for the same physical inbox.

jcranmer3• 8 years ago

To emphasize your point: don't touch email addresses. You can get away with doing equality checks on NFKC case folding, but don't assume that you can store a lowercased email address and have it work properly.

Lots of weird email systems exist. Don't assume that everybody works like gmail. And do test that things work right with uppercase letters in email addresses: I've been locked out of systems before because I use an uppercase letter in my email address and one half of the system was trying to match the lower cased version to the actual text.

ubernostrum10• 8 years ago

Unfortunately, Gmail rules the world and has trained people to expect that they can be sloppy and inconsistent and enter their email address as 'johndoe' or 'john.doe' or 'JohnDoe' or 'John.Doe'... etc. and it just works, I don't understand why your site is broken, because my email works!

And when that happens, trying to patiently pull a "well, technically" and explain to them about RFC this and the specs say that is a way to lose users.

(I actually have extremely strong feelings about email, email addresses and the whole associated mess of specs, but had to tone it down for this article since it was mostly about the various traps you can wander into from naïvely thinking that you can just read a spec or implement something obvious and get away with it)

inopinatus5• 8 years ago

The local part (left of the @) of email addresses is case sensitive by definition and this should not be controversial.

RFC5321 s2.4:

   The local-part of a mailbox MUST BE treated as case sensitive.
   Therefore, SMTP implementations MUST take care to preserve the case
   of mailbox local-parts.  In particular, for some hosts, the user
   "smith" is different from the user "Smith".

Even though it goes on to say:

   However, exploiting the case sensitivity of mailbox local-parts impedes
   interoperability and is discouraged.

This doesn't prohibit a local delivery agent (such as Gmail) consolidating multiple variants into one mailbox, but everything up until that point must refrain from making assumptions.

neltnerb• 8 years ago

Oh, I assumed the recommendation was to store the actual email address as entered, and then also generate the fingerprint to compare for similarity. Wouldn't you just keep both?

Alex39175• 8 years ago

it's not your identity system's job to deduplicate different logical addresses for the same physical inbox.

The problem is that then you're adding potential attack vectors to every single web app just to cater to the .01% of email clients that insist on implementing the email RFC exactly to spec. Not deduplicating email addresses creates an attack surface for both hard-to-spot technical issues and also social engineering attacks. E.g. what if your ESP at some point adds deduplication on their end, either mistakenly or on purpose, then suddenly you're sending password reset requests to the wrong users.

I think you should normalize email addresses to enforce account uniqueness, both for security purposes and usability, as long as you also store a second copy of the email address exactly as the user entered it and only send email to the latter version.

djsumdog• 8 years ago

At most you're allowing duplicate accounts to the same e-mail address. If you want to enforce 1 to 1 identities with e-mail accounts, you could have an issue. But in general, it shouldn't be a security concern.

caf• 8 years ago

Yes. The answer to the question posed in the article is actually simple - there are 3 unique email addresses listed. The fact that email addressed to some of them may end up in the same box is neither here nor there.

Alex39175• 8 years ago

The fact that email addressed to some of them may end up in the same box is neither here nor there.

It's not an issue if they're the same, the issue is if they're different. E.g. if I'm storing bitcoin on an exchange (I know) behind the email@domain.com, then I don't want someone else to be able to register Email@domain.com and then start looking for bugs in the service or start trying to socially engineer customer support. (The local part of the email address is case sensitive as per the spec.)

quickthrower22• 8 years ago

the best way is to err on the side of allowing a single email inbox to create multiple accounts.

Who cares if they do? It's not like that person couldn't create multiple email addresses anyway. E.g. abc@gmail.com and def@gmail.com can be the same person. You can't validate for that, other than other "gamification" systems (e.g. how HN treats new users - disincentivizes creating multiple accounts because why be limited on your second one when you have a good first one).

by the way I have used the + trick on google to sign up for a service (and pay for it!) that wouldn't let me reuse my old account for some reason. So their relaxed validation made them money.

zbentley8• 8 years ago

It's a difference in difficulty. More to the point, it's a difference in asymmetry of difficulty.

Say you run an online store. You offer USD $5 in first-time user credit.

A lot of people (even some nontechies I know) know about the "+" trick for gmail. Assuming your signup flow is easy and fast, it's very easy for those people to sign up for multiple accounts and get multiple $5 credits.

If a lot of people do that, it might significantly impact your bottom line. Not just because you have to give away a lot of inventory, but secondary effects also suck: you stop the $5-free promotional, and then all of the legitimate users who signed up during the campaign who told their friends to sign up and get some free money now have their friends bad-mouthing the site to them because "it didn't give me free shit the way you told me I should expect it to!". You might see a drop in sign-ups to below pre-promotional levels, or, worse, you might see people who signed up during the promotional trust and use your site less. I know trends/behaviors like this seem trivial--and they definitely would only affect a minority of users--but past a certain scale effects like those can have a real financial impact.

Now let's say your site is "smart" about the "+" trick and doesn't let people with gmail (or google-federated emails--boy, is figuring that out a bastard) accounts sign up multiple times. You'll lose the dubious potential business of folks who like gaming promotionals. You'll still be vulnerable to people creating second email accounts and signing up using those--but the difficulty asymmetry now favors you, the vendor: it's work for a user to make a second email account; work they probably won't do, especially if you blacklist typical temp email services like guerillamail. If the promotional is large enough to entice first-time users but small enough to deter people from doing this, you have succeeded in minimizing your loss. If the user already has a fleet of accounts for this purpose they're probably going to just take your money anyway.

Of course, there's another more annoying scenario which I'll mention because sites should never do it: sites that think they're being smart about the "+" trick by not storing the part of the address between the plus and the domain part. This is usually done to get email campaigns (read: almost entirely spam) to show up in the user's main mailbox rather than some filter-purgatory. It will drive users away in two main ways: first, if I'm technical enough to use the "+" trick and a filter to route mail, I probably have enough obsessive annoyance with spam to immediately either junk-flag yours or delete my account, compared to a small chance I would have actually read it otherwise. Second, more than half of sites that do this which I've audited parse and strip the content of the email address wrongly (parsing emails is very hard, after all) in such a way that what they end up storing could be a totally different person's email, or an invalid one. That means signups just won't work. Whatever you do, don't do this.

This doesn't only apply to first-time-user promotionals, either. It also applies to:

- Referral bonus programs.

- Services that give hand-customized products to users (think a "one per user" etsy store with one person knitting cat dolls or something): multiple similar contacts from the same user would mean you spend a lot of time making their products--time which might be wasted, even if they paid for their products, compared with time spent making them for lots of different users and increasing your recognition/exposure.

- The same applies to tech-support contact-us forms: one user can "bogart" your support staff, clogging the queue with (legitimate or not) requests and defeat your rate limiters by using the "+" trick, making other users wait a long time for replies.

- Others I haven't thought of.

nodesocket• 8 years ago

Completely agree. If somebody wants to signup for your service as ceo@company.com and ceo+sales@company.com let them. Two distinct user accounts.

nzjrs• 8 years ago

Dear sir. I enjoyed your free trial. May I have+1 another?

tbabb• 8 years ago

My thought would be to have two distinct fields: "normalized" and "pristine" version of the user's email. Then always mail to exactly what the user typed ("pristine"), and use the "normalized" mail to prevent multiple registrations to "john.doe@gmail" and "johndoe@gmail" and "johndoe+1@gmail" and "JOHNDOE@gmail.com" and so on.

Denying registration to a suspected-duplicate seems a lot safer than mailing to a different person.

__david__• 8 years ago

If you're going to do that then only do it for email addresses where you understand the local MTA conventions (like gmail). Do not do it for domains you don't know (because you cannot predict how they work).

For instance, on my email domain, david+abc@example.com, david.def@example.com, and david_ghi@example.com are all the same ('+', '.' and '_' all act like you'd expect '+' to), but david+xyz@example.com is not (it get's picked off and aliased somewhere else). Applying gmail conventions to other domains is silly and wrong.

pawelk• 8 years ago

You can still do a check for the normalized address for known sevices that allow moving the dots and adding a +somthing (e.g. to catch someone creating multiple fake accounts). Just be decent about it and store the user-provided address for communication purposes.

sarreph• 8 years ago

It does surprise me how many big SAAS products with generous free trials don't check for '+'s on Gmail addresses...

IgorPartola• 8 years ago

I agree with everything here except the email addresses example. Yes I do want to register igor@example.com and igor+work@example.com. Those are different accounts, please don’t mess with that.

yeukhon• 8 years ago

I also employ the dot scheme for different purposes. Example: johndoe.hn@gmail.com vs johndoe.school@gmail.com so I wouldn’t want anyone aliases without the dot.

zbentley8• 8 years ago

There may be very good reasons for a site operator to disallow this. I mentioned some of them elsewhere in these comments: https://news.ycombinator.com/item?id=16358625

pc863• 8 years ago

For things that are legitimately tied to your physical identity as opposed to an email address it makes sense not to let you do this.

Spivak• 8 years ago

So if you’re enforcing unique email addresses, or using email addresses as a user identifier, you need to be aware of this and you probably need to strip all dot characters from the local-part, along with + and any text after it, before doing your uniqueness check. Currently django-registration doesn’t do this, but I have plans to add it in the 3.x series.

Isn't this a really dangerous game to play? Just because some major MTA's assign a class of addresses to each user doesn't make each member of that class not a unique identifier in general. Is it worth the headache to maintain a list of various email systems' policies rather than just treating them all as unique?

jcranmer3• 8 years ago

The email RFCs explicitly say thou shalt not interpret the localpart of an email address, unless thou art the MTA of the domain in question. Even case folding is forbidden. And the wisdom of people who work with email is... the RFCs have good advice here: don't assume anything about how the localpart is structured.

You can generally get away with treating the names as case-preserving (as distinct from case-insensitivity), and you are probably safe in rejecting quoted localparts. But beyond that, even forcibly lowercasing email addresses, is likely to cause problems.

ubernostrum10• 8 years ago

Like it or not, the RFCs have lost. "How Gmail does it" is now how email works in the minds of a stupendous number of people. So if Google says 'johndoe' and 'john.doe' are the same, we're stuck with the reality that 'johndoe' and 'john.doe' are the same.

EGreg5• 8 years ago

Why have usernames at all?

Think about it ... people who have you in their addressbook already have nicknames for you.

People who you let see your first and last name can already see that.

About the rest of the people - why do they care?

Only because you want your REPUTATION to be communicated to others in English. Hey it's "someguy22"!!

Yeah that's a pretty limited thing. Could be useful but really, how often do we remember names of others? Only celebrities. And who actually cares about Aziz Ansari and his sex life? Or any of the other dudes who we never met? Or why is one dude "the" Bill Gates and the others with same name are not verified by Twitter? My point is, think about what is the sociological meaning behind usernames.

kuschku6• 8 years ago

So, how should mail services handle emails accounts?

1004383737289302@example.tld ?

EGreg5• 8 years ago

Email John

Otherwise how did you come across John's email? SPAM?

always_good5• 8 years ago

I recognize people's usernames all the time on HN (including yours) and other communities. I gravitate towards people who write good stuff and I learn to avoid the usernames of people that are unreasonable.

I'd say it's less about broadcasting your reputation and more about letting other people make that judgement about you out of their own interest.

jancsika• 8 years ago

3. Public identity, suitable for displaying to other users

Many sites-- like HN-- may not even need that. If you have system and login identity you can just display "dingus" as the name of every single user and the system should still work the same.

grzm2• 8 years ago

I think without display names having discussions would be difficult, as people find some identifier useful to follow along. Even if it's a pseudonym, it's hard to build a sense of community without being able to distinguish those in your community. Or am I misreading you?

Anon1096• 8 years ago

4chan and other imageboards manage to have discussion fine without unique identifiers.

AnabeeKnox• 8 years ago

For PHP, see the Spoofchecker class for similar functionality to the Python class discussed in the article.

http://php.net/manual/en/class.spoofchecker.php

ne01• 8 years ago

Well, it’s easy until we start thinking about case. If you’re registered as john_doe, what happens if I register as JOHN_DOE?

For most applications you are better off with making everything NOT case sensitive.

That's why SunSed language is completely case insensitive -- from variable names, tags (functions) to all string comparations. Users should not worry about case!

leoc2• 8 years ago

Doesn't case insensitivity combine poorly with (fairly unrestricted use of) Unicode though?

ghalvatzakis2• 8 years ago

My Linkedin username: https://www.linkedin.com/in/Αdmin/

edent• 8 years ago

Brilliant! Does it cause you any problems?

ghalvatzakis2• 8 years ago

I'm using this username for about 6 months now. No problems so far...

badsectoracula3• 8 years ago

It is certainly slower but what i always did even back around 1999-2000 when i first learned web programming, was to simply query the user db to see if any user exists with the requested username before even doing anything else. Also at some point i decided to also store a "broken down" version of the username with symbols removed, Os replaced with zeroes, etc and check against that.

Also i never allowed less than two letters and characters that weren't numbers, latin letters, a space and a few punctuation symbols.

jarofgreen2• 8 years ago

What we really want in terms of identifying users is some combination of:
System-level identifier, suitable for use as a target of foreign keys in our database
Login identifier, suitable for use in performing a credential check
Public identity, suitable for displaying to other users

Some sites want a fourth one:

Public Identity, suitable for other users to use to refer to each other.

Like on Twitter: "Discussed this with @bob and @jane yesterday, you'll find ..."

Now, you don't need a unique username to be able to meet this requirement - StackOverflow is an example of a site that handles this I think? But having a unique username is a common pattern that many sites use to solve this so it seems worth mentioning.

dmitriid• 8 years ago

With all the unicode problems I'm surprised so few languages include ICU which has everything unicode-related. Things mentioned in the article:

- Normalization: http://userguide.icu-project.org/transforms/normalization

- Confusables: http://icu-project.org/apiref/icu4j/com/ibm/icu/text/SpoofCh...

(and there are so many more things)

PokemonNoGo• 8 years ago

I like how many system have problems with surrogate-pairs and the shy hyphen \xad. I just the other week had a support issue where I had used the very special character of - (dash) in my email...

Also Atlassian Stride doesn't support sending the \xad character at all. It just fails...

\xad makes me \sad

GoToRO• 8 years ago

Meanwhile I haven't found a good way to know my Skype user name (or id?). My account was migrated to Skype from Outlook I guess and it is something like "live:username" but people can't really find me with that. I take full blame if it turns out that I just don't know how to use Skype...

c12• 8 years ago

I'm currently working on an service and have put a lot of thought into about seven tenths of what is said in this article.

This is a very good read and one I have bookmarked to share with colleagues.

qwerty456127• 8 years ago

I actually loved the concept of bare-number UINs used in ICQ back in the days when ICQ and AOL dominated the messengers market. Those were neutral, easy to share vocally, allowed mutable non-unique screen names and e-mails. That's a pity people don't use them any more.

stasel• 8 years ago

Worth mentioning Spotify's account hijacking problem when using unicode https://labs.spotify.com/2013/06/18/creative-usernames/

fileeditview• 8 years ago

I somehow lost my old HN account and had to register a new one not so long ago. After trying a multitude of user names I surrendered and just copied words from the browser menu bar. This is what I ended up with :)

I always wondered why we don't use emails as (unique) login names generally. I mean they can be shown with wildcards if that is the concern?!

sethammons• 8 years ago

I generally agree. But we've had customers who share an email address, whether businesses or personal, who want distinct accounts on our site.

M2Ys4U• 8 years ago

I'm surprised nobody has mentioned PRECIS - the framework for Preparation, Enforcement, and Comparison of Internationalized Strings in Application Protocols[0].

It defines a (small) set of profiles to validate and compare various types of string, including "Username" (in both case folded and case prepared variants) and "Nickname".

Want to compare two usernames for equality? Run the two strings through the comparison steps for the UsernameCaseMapped[1] profile.

It won't solve all of your problems, but it's a good place to start.

[0] https://tools.ietf.org/html/rfc8264

[1] https://tools.ietf.org/html/rfc8265#section-3.3

teisman• 8 years ago

For my website, normally I'd be in favor of allowing users to create multiple accounts with variations of email addresses (e.g. foo@example.com, foo+bar@example.com, f.oo@example.com). I sometimes create multiple accounts like that myself as well.

Coincidentally, today a spammer is creating hundreds of accounts with such variations of the same email (gmail) address -- something that should be stopped right away.

Paianni• 8 years ago

My strategy is to think of a name so unique that no one else would think of using it. The one on my HN account I originally cooked up in Nov. 2014, and I never had to extend it with numbers to get it accepted on various forums (yes, most of them were fine with changing the nick). My biggest gripe is that since YT changed their username system in October of that year, my most popular channel is stuck on an old username despite being a few months older.

pc863• 8 years ago

Many systems ask the username to fulfill all three of these roles, which is probably wrong.

What system with any non-trivial level of use uses the text username as (1) the FK in the database, as opposed to the generated or auto-incremented ID in the db; (2) the login name; and (3) the publicly-displayed displayed "name" of the user for others to see?

Plenty of forums etc use the login name for #2 and #3, and I'm not convinced by this article that that's the wrong way to do it. I haven't ever seen a single professional product that uses the text username that a user logs in with as the actual DB-level foreign key. That's grade school level database design.

cjslep• 8 years ago

When logging in, how do you get that autoincremented ID column? Some more complex variant of "SELECT *.id WHERE username = $1". So functionally, yes the username is the root identifier that pulls the very first record that then allows other joins to occur. But you are right, the username column is not literally the key being joined on.

There is also the security issue that by having the login name also be the publicly displayed name lowers the bar for attempting to make a targeted attack on the site, as well as other sites where the attacker suspects the victim may be using the similar login name. This can particularly be true in cases of harassment across platforms, which while is not a computer science security issue, it is a personal psychological security issue.

always_good5• 8 years ago

Though I haven't seen too many systems where the static login name is actually hidden from the world. It seems to just end up being the canonical ID, so right there in every permalink or whatever.

bpicolo• 8 years ago

the username column is not literally the key being joined on

That's exactly the point though. If you join on the username than allowing emails/usernames or whatever that identifier is to be edited is very hard. How you identify the row to auth against is literally the point of a username.

flurdy3• 8 years ago

One of the reasons I made my own bad username lookup. https://github.com/flurdy/bad_usernames Its a simple json file of usernames to disallow.

It does not address many of the other things higlighted in this post but it is a start, at least for my services.

nekopa2• 8 years ago

In the en version of your file I don't see any of the common c-level words: ceo, cfo etc...

flurdy3• 8 years ago

So if you’re enforcing unique email addresses, or using email addresses as a user identifier, you need to be aware of this and you probably need to strip all dot characters from the local-part, along with + and any text after it, before doing your uniqueness check. Currently django-registration doesn’t do this, but I have plans to add it in the 3.x series.

Sorry what? That seems pretty unneccessary. A third party system to dictate how a third party system handles it local alias system for emails? I can't see any benefit to that.

Whether a mail server handles '+' in a standard way is not guaranteed, and surely it is up to the user how they use that feature if enabled.

dharmab• 8 years ago

If you don't do this your system may allow users to sign up for multiple accounts and double-dip on signup benefits, free trials and other "one per account" features. (Barring additional controls, of course).

eli• 8 years ago

Well, that's always a risk. The thing this guards against is someone accidentally creating two accounts with variations on the same address and being very confused.

aeruder• 8 years ago

Or they could just sign up at one of the numerous free email providers with a different username. Stripping the + suffixes is only providing one thing - pain for the users that want to use it.

tjoff5• 8 years ago

If you as a service provider can't accept that you shouldn't be offering those free trials / benefits at all. This isn't an issue.

Coryodaniel• 8 years ago

You’re gonna be sad to know that mailinator[1] and it’s 100s of domain aliases exist.

You’re fighting the wrong battle.

[1] https://www.mailinator.com/

sosilkj• 8 years ago

Agreed.

From RFC 2822: "The local-part portion is a domain dependent string."

Headaches await you if your code is making a lot of assumptions about how the originating domain manages that local-part portion.

oakesm9• 8 years ago

Apple ID's make assumptions (they strip out the + and everything after it) and it's made it a nightmare to use iTunes Connect. Their multiple account support is still terrible so it's easiest to have an Apple ID per iTunes Connect account. Now I need to setup actual aliases in my GSuite account...

lentil_soup• 8 years ago

Absolutely this. It's not even a standards issue, for the outside world they're completely different email addresses. The fact that they happen to land on the same inbox for some providers is unrelated, it's just how that particular provider decided to handle all your different email accounts.

dalore• 8 years ago

Yes! And if you have your own domain, you can just setup a *@example.com to be your one email address. And then you can give a different email address out anyway even without needing to go +. As you said each system can treat it differently.

detaro• 8 years ago

Agreed. The + thing probably is "only" unfriendly to powerusers, but stripping dots can easily get in the way. Several of my e-mail addresses have "duplicates" that just differ in a dot and are owned by entirely different people.

Glyptodon• 8 years ago

I was with him most of the way, but the advice about emails seems very user hostile to me.

yxhuvud• 8 years ago

Stripping out things past the + will also break things for users that intentionally are creating more than one signup. This seems like a really bad idea.

LambdaComplex• 8 years ago

That's the entire point, no?

jelder• 8 years ago

Agree. You're going to regret doing this when you try to test it yourself, with your own Gmail (or GSuite) account.

pfooti• 8 years ago

yeah, I actually use google's plus-email features to help me generate test accounts on some sites or to attribute mail spam to other sites.

kevin_b_er2• 8 years ago

so it’s impossible without doing DNS lookups to figure out whether someone’s mail provider actually thinks johndoe and john.doe are distinct.

The author has announced they believe them to intentionally indistinct and has announce an intent to break handling for any mail servers that consider them unique. All on account of gmail ignoring them?

This coupled with their author's intent around + makes me loathe this behavior.

adrianratnapala• 8 years ago

It is worse than unnecessary. If people start irrationally doing things like recognizing the '+' then that creates facts on the ground which rational reasons for others to have to recognize the '+' -- except nobody really knows why anyone is doing it or what semantics anyone else is using. Thus the whole thing evolves into mess.

So please don't do that. Respect the bytes that be!

timvdalen2• 8 years ago

So if you’re enforcing unique email addresses, or using email addresses as a user identifier, you need to be aware of this and you probably need to strip all dot characters from the local-part, along with + and any text after it, before doing your uniqueness check.

Please don't do this, lots of people (including myself) use the '+' hack to separate accounts for different contexts (business/personal, different projects/clients, etc).

jrimbault• 8 years ago

I think he wasn't proposing to remove the '+' part from the address stored, but splitting the address into smaller parts when doing the unicode verification and checking if there's isn't already a 'john.doe+xxx' when you register with 'john.doe+yyy'.

Ajedi32• 8 years ago

Which is just as bad, since now you need to create an entirely new email account just to have two accounts on the same service.

timvdalen2• 8 years ago

I realize that. What I'm trying to say is that I like to create 'john.doe+projectA@example.com' and 'john.doe+projectB@example.com' accounts with some services.

Checking for the existence of any 'john.doe@example.com'-like accounts would mean I have to register an entirely separate email account or set up (another) email forwarder/alias.

kevin_b_er2• 8 years ago

Also proposing to ignore all dots (.) on account of GMail doing that, while a moment before saying how that behavior is different. So they will break the experience for two people on a dot-unique mail server.

todd38342• 8 years ago

making usernames case-insensitive would be a massive backwards-compatibility break and nobody’s sure whether or how we could actually do it.

Couldn’t you store an upcase version of the username that is unique for this? You would still keep both columns so you have the upcase version for uniqueness and the original column for display name. This would also be backward compatible.

todd38342• 8 years ago

An upgrade script can find collisions and report them before you upgrade. You’ll be required to resolve those before enabling case insensitive user names.

metalliqaz• 8 years ago

This is a great article, thanks.

styfle• 8 years ago

Somewhat of a tangent:

I somehow created a Reddit account without an email address in order to comment on something about 8 years ago.

Eventually, I decided to comment on something else but forgot the password.

I was unable to reset the password without an email address.

So I never commented on Reddit again...I don't want a username that isn't styfle :)

zeveb2• 8 years ago

So if you’re enforcing unique email addresses, or using email addresses as a user identifier, you need to be aware of this and you probably need to strip all dot characters from the local-part, along with + and any text after it, before doing your uniqueness check. Currently django-registration doesn’t do this, but I have plans to add it in the 3.x series.

This is needlessly user-hostile. If users wish to use mailbox extensions to have multiple unique accounts, that's their right. They can always get multiple different email accounts, after all.

He doesn't mention the one thing he ought to do, which is to strip email addresses of comments before checking them: (foo)jdoe@example.com, jdoe(bar)@example.com, jdoe@example.com, jdoe@(home)example.com & (a (nested (comment)))jdoe(more)@example.com(all done) are all the same email address.

mhandley2• 8 years ago

When it comes to email address normalization, it sounds like we could do with a standardized way for a domain to express normalization policies.

Could be as simple as publishing a set of regular expression subsitution rules, specifying (for example):

* render to lower case (because this particular domain is case insensitive)

* drop periods (because this domain treats them like gmail does)

* drop '+' and any subsequent characters (because this domain treats them like gmail does)

* ASCII only (because mail software is old, and doesn't support unicode)

Etc.

Each domain could then publish their own rule, perhaps in a DNS txt record, and anyone needing to check if two email addresses alias to the same could run the correct checks.

ino• 8 years ago

Some users capitalize their email address, and they expect to see it capitalized.

I think a better solution would be to use a case insensitive collation on the database for the email column.

If the user changes the capitalization of their email, treat it like any other email change (validate the new email via email token)

jedberg2• 8 years ago

In my 20 years of experience validating email addresses, I've found one thing that works every time without fail:

Send email to it

That is literally the only way to validate an email address. There is no regular expression or algorithm that can validate and/or deduplicate an email address.

You must simply treat every email as unique until you send an email to it and that person proves otherwise.

That being said, this article brings up a lot of important things about confusables that everyone should definitely be aware of, especially if you're going to have public identities.

gitgud2• 8 years ago

How does sending email to it prove it's not a duplicate? For example:

    john.doe@gmail.com

    johndoe@gmail.com

Both resolve to the same email at the users end.

jedberg2• 8 years ago

Exactly, and then the consumer clicks a link to verify their email and they have a second account, and it's up to them to put them together, or up to you to see that they already have a login cookie and combine the accounts.

Spooks• 8 years ago

well with gmail they are the same email. But with other mail applications, those could be two different email addresses. You are going to need to test all the different email services and find out which do this and which do not do this... which is no easy task

oscarhult• 8 years ago

Creative usernames and Spotify account hijacking Posted on June 18, 2013 https://labs.spotify.com/2013/06/18/creative-usernames/

ngneer• 8 years ago

https://en.wikipedia.org/wiki/Zooko%27s_triangle

hendry• 8 years ago

I don't see what is wrong with treating a email as a username.

I wonder if Auth0 or Cognito resolve any of these issues.

Let’s talk about usernames

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