Linking secondary devices

[madduck]

The proprietary WhatsApp client can authenticate other clients, such as WhatsApp Web. To link such a secondary device, a QR code generated on the secondary device is scanned by the primary client. Presumably, this is a public key, signed by the primary client, then uploaded to the WhatsApp servers, thus giving the secondary client access to the account. I don't know the details of this (yet), but it's probably the same as what Signal is doing.

If yowsup were able to sign keys like this, i.e. I scan the QR code, obtain the key in plain text, feed it to yowsup, which then uploads the signed key to the WA servers, I could write a yowsup dummy client that just stays online — thus fulfilling the requirement not to be offline for more than 14 days, else your linked devices get unlinked — dropping all content, and I could use a secondary device (e.g. a Matrix bridge) for all my WhatsApp needs.

Is this something worth considering?

[tgalal]

It is something indeed worth considering, although unfortunately no time from my side to implement it for the time being.