[Foundation-l] Single login - decision 2004

Erik Moeller erik_moeller at gmx.de
Fri Nov 12 03:27:00 UTC 2004


there's been some movement forward on the Single User Login (SUL) issue. I  
ask the Board to review this mail carefully as this has significant long- 
term implications and we need Board input to go ahead. I also ask other  
developers to correct me if I misrepresent anything.

There are currently three competing strategies. Before I describe these  
strategies, let me point out that one important consideration for any  
system is scalability. That is, single login will be used on all existing  
and future Wikimedia projects, and potentially even on non-Wikimedia sites  
which we allow to participate in our system.

The three strategies are:


We try to move towards a single global user namespace for all Wikimedia  
wikis. If a name is already taken in the global namespace, you have to  
find one which isn't.

For the migration, any names which clearly belong to the same user are  
combined into one. If passwords and email addresses are different, the  
user can manually link together any accounts which belong to him by  
providing the passwords.

For cases of true name conflicts between the existing wikis, there is a  
resolution phase, where factors like seniority, use on multiple wikis vs.  
a single one, etc., are weighed in - the "loser" has to choose a new  
account name.

After the manual resolution phase, any remaining accounts are converted to  
the new system automatically by making them unique, e.g. by adding a  
number to the username. The transition is now complete. The old system no  
longer exists.


As in 1), we migrate all existing accounts to the new global namespace  
automatically if possible. New accounts are created in the global  

Where there are people sharing the same name, the accounts will not be  
migrated to the global namespace but will stay in the local ones, which  
will continue to coexist. These people can keep using their local IDs, or  
create a new, different global identity.

The idea here is that resolving name conflicts is so complicated that we  
simply defer the issue for now.


Every user has a global, numeric ID which is unique. But for each wiki,  
they can have a different username. As in strategy 1), any clearly  
identical accounts will be linked to a single GUID automatically, others  
can be hooked up by providing the passwords.

Naming conflicts are not an issue in this system. Let's say I am Eloquence  
on en: and de:, and there is another Eloquence on fr:. I get the global ID  
1233, the fr: user gets the ID 28387. When I go to fr: and try to edit a  
page, I get a prompt:

         The username you have chosen is already in use on this wiki.
         Please specify a new name:

         If this is your account and it has not been linked to your
         global ID yet, please provide the password:

If I go to another wiki with no user named Eloquence on it, however, the  
local username "Eloquence" will be reserved for me the moment I edit it or  
set my local prefs. This is because the system knows that "Eloquence" is  
my preferred username, and will automatically try to create it for me when  
I need it.  I can change the name later, if I want, and use different  
names on different wikis.

- - - - -

The differences:

1) is very complex, and we may not find someone willing to deal with the  
name conflict resolution issue and take the blame from annoyed users at  
the same time. Naming conflicts will always be an issue in this scheme, as  
e.g. all common first names will be taken, and any small wiki hooking up  
with our SUL system would feel this impact. People can mutate these  
usernames relatively easily to make them unique - Erik333 - and the system  
can offer such mutations, but it's still a bit annoying.

2) is easiest to implement by avoiding the conflict issue. Brion has  
expressed interest in coding this. It will annoy some people who can  
choose between using their local name and keeping their attributions, or a  
global one, and losing their attributions, at least until things like  
linking up local accounts to a global one are implemented. It leads to  
some ugliness in the system because we are in an "in-between" state for  

3) does not have the naming conflict problem. Both Jamesday and Kate have  
expressed interest in implementing it. Jamesday also wants to write a more  
detailed proposal on Meta about it. For the user, it is fairly straight- 
forward -- existing accounts can be hooked up easily to the single login,  
new names are picked only when necessary. It is somewhat vulnerable to  
trolling, as someone could e.g. register the name Eloquence on a wiki  
where I am not active, and use it for nefarious purposes. The system could  
however make it fairly easy to find out that this is not the same person  
(on the user page: "This user is active on the following wikis: .. under  
these names: ..").

In any case, we want username changes to be a cheap operation, so that  
anti-trolling policies should be easily enforcable.

The question for the Board is: Given that we have at least two, and  
possibly three, implementations where there are volunteers, which one  
should we choose? To me, this seems to be a matter that could be decided  
by the Board; others have said that a poll will be necessary first. Either  
way is fine with me - what does the Board say?



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