Files using E2E encryption cannot be decrypted

[aperezdc]

The error is:

Unable to decrypt attachment:
  - TypeError: undefined is not an object (evaluating window.crypto.subtle.importKey')

[aperezdc]

Checked this with the WebKitGTK+ folks, the TL;DR is:

• Subtle Crypto is a lower-level component typically used to implement Web Crypto.
• There used to be support for Subtle Crypto, but its tests got broken when the Web Crypto API was implemented.
• Nobody has had the time yet to look into it, so Subtle Crypto was disabled because anyway web sites are expected to use the higher-level Web Crypto API instead, so fixing it is not a priority.

[uhoreg]

Also seemingly affected by lack of subtle crypto: unable to use the new key import/export feature.

[aperezdc]

I have pushed a new version to the Flatpak repository (0ec092f400dd) which uses the GNOME 3.26 runtime, which in turn includes WebKitGTK+ 2.18 with WebCrypto support. This seems to work now.