idea: match phone numbers (hashes) with existing JIDs

[workoft]

Hi,
I am not sure if this is the right place to post this. I am currently in China and I can't access the google groups forums, not even with VPN.
I very much like the idea behind Kontalk, it's actually very similar to an idea of my own that I had a while back but never put into practice due to lack of time and knowledge.

The concept of Kontalk is missing one thing: Because of its interoperability with other XMPP based services, many XMPP users (including me) will just decide to simply stick with what they have, since they can communicate with Kontalk users anyway. This defeats the purpose of a service like Kontalk to some degree: If those people don't sign up with Kontalk, Kontalk users will not be able to find them using their phone numbers. Address book matching is one of the killer features that helped WhatsApp to its success. It would be a pity, to have a semi-working variant in Kontalk.
So here is my idea: Offer, in addition, an option to use an existing XMPP account on a server of choice (or create one), but store an XMPP-ID/phone number hash on a server where it can be found by other Kontalk users. Users can then proceed to send friend requests to the matches found.

This approach has additional advantages:
Your user name will stay the same even when you change phone numbers. As somebody who changes countries every now and then, I have never understood why people hold on to country-dependent, non-mnemonic IDs so much.
You could register more than one phone number. Many people have more than one number, whether it's numbers from different countries or the same country (for whatever reason). In China for example Dual SIM phones are very popular because many of the cheaper mobile phone plans charge higher fees outside the province the SIM card was bought. You could even inform a user when his contact updated his phone number. The user's client could then request the new number from the contact and update the address book automatically.
Kontalk-IDs could be shorter. If this approach is also used internally for "pure" Kontalk users, the IDs won't have to be hashes anymore - a much shorter random ID may be assigned and matched with the hash. This would make it a lot easier to exchange contact details with somebody who didn't register his phone number at all. Currently, Kontalk doesn't seem to allow adding vanilla XMPP users unless they send a friend request first and adding a Kontalk user on vanilla XMPP can be cumbersome when no previous digital communication channel has been established that the longish ID can be sent over.

Wechat, China's most popular mobile instant messenger requires a username and a password to log in. An account can be matched with a phone number, an email address and a QQ ID. When a match from the address book is found to be using Wechat, the account is suggested to the user, including the account name/profile picture and the phone number the user was found by. The user can then decide to send that person a friend request. I can change my registered phone number any time. If someone else registers with a phone number I used previously, my account will no longer be matched with that phone number.
This is exactly the kind of behaviour I want for XMPP. Kontalk could provide both this AND the no username/no password simplicity that WhatsApp and many others provide.

Thanks guys and keep up the good work!

[abika]

Thanks for your input! This is highly related to kontalk/androidclient#497 and even extending it:

• a Kontalk JID can be linked to multiple phone numbers and the phone numbers can change
• non-Kontalk accounts can be added to the JID<->phone number map

Both will require complex verification mechanisms and the latter is problematic: Note that Kontalk is much more than XMPP plus phone numbers. Although basic messages can be exchanged just fine, features like encryption or file transfer won't work out of the box. So using an exiting Jabber account can't have the same functionality a new Kontalk account has.

[mvdkleijn]

Just discovered Kontalk but look very nice so far, only missing the group chat.

I have two remarks concerning group chat and this issue, well... one concern and one request actually. (Please let me know if this belongs in a separate issue, I'll be happy to open one)

1. When using guessable IDs, please make sure we don't / can't get spam messages from random people like we used to have on ICQ.
2. Would it be possible somehow to add people to your group without disclosing your email or phone number?

An interesting use case is becoming very popular over here: people add everyone in the neighborhood to a WhatsApp group as a form of neighborhood watch. It has proven very effective against burglars and such.

While I like that idea, I don't like sharing my phone number or email with a 100 people, most of whom I don't know.