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The protocol is open but key exchange is not: even on Android, third-party messengers can’t interoperate with Google Messages. See page 11 of that PDF.
by acdha 2y ago
The protocol is open but key exchange is not: even on Android, third-party messengers can’t interoperate with Google Messages. See page 11 of that PDF.
- g-b-r 2y agoThat text seems more a reflection of the fact that only Messages supported it, when the document was written If they seriously wanted random third parties to implement it, anyhow, they'd have published a specification, not an "overview"
- acdha 2y agoOnly Messages was allowed to support it. At the time it was written, for example, it was years after the Signal developers had asked for basic RCS support (2015) and given up on Google relenting and allowing it in 2018. https://github.com/signalapp/Signal-Android/issues/4837 https://github.com/signalapp/Signal-Android/issues/4837
- g-b-r 2y agoDid you read that issue? It's Moxie that refused to support it
- acdha 2y agoYes, I followed it when it was open. Which third-party app do you use which supports RCS E2EE?
- g-b-r 2y agoNone, but that issue has no mention of what you said in the other message ("Only Messages was allowed to support it. At the time it was written, for example, it was years after the Signal developers had asked for basic RCS support (2015) and given up on Google relenting and allowing it in 2018")
- jeroenhd 2y agoSignal has been rather dismissive of RCS in general. Of course RCS was as insecure and unencrypted as regular SMS/MMS until now, but I haven't found a sign that Signal ever even looked into supporting RCS at all. At this point I think they just wanted to get rid of their SMS backup feature and used RCS as an excuse.
- acdha 2y agoSignal was dismissive of unencrypted messaging. Google used their protocol for their proprietary E2EE system so it’s unlikely that this objection would apply if that system was open. Put another way, if this was a Signal thing what other Android app is doing this?
- jeroenhd 2y agoThat's true, but Google has also indicated that they're switching to the GSMA spec which is intended for interoperability. I also doubt that Google would withhold such details from parties like Apple even if they maintained their proprietary format. Small developers would need to reverse engineer the details, unfortunately.
- acdha 2y agoMy question is basically whether they open it up or limit it to companies they have deals with. Reverse engineering is a risky game for a service with device checks since that’s potentially a CFAA violation and it could lead to your users getting their hardware banned.