signTextJS plus v0.9.6 
This extension requires a native back end. See the homepage for details.
window.crypto.signText is a digital signature technology that has been available since 1998. It is used by government and banking sites. It can be used to participate in plebiscites.
The window.crypto interfaces were removed from Firefox 35 and later releases. An add-on was developed as a stop-gap measure for users; that add-on is deprecated and does not work since Firefox 57.
signTextJS plus takes over this technology. It restores automatic signatures and filtering by certificate authority, and provides these enhancements:
- An asynchronous mode.
- Filtering by non-repudiation.
- SHA-256 support.