Matrix Encrypt Attachment

Encrypt and decrypt attachments in accordance with the Matrix Client-Server API spec.

Supports browsers using WebCryptoAPI and Node.js via crypto.

This project builds on and deprecates browser-encrypt-attachment to add support for non-browser environments.

Protocol versions

Previous versions of the protocol are not currently documented in the spec, and are described here for reference:

Protocol	Description
v0	use all 128 bits of the counter
v1	use only 64 bits of the counter
v2 (current)	use only 64 bits and also zero out the other half to maximise the space before it wraps

Encryption

The library will encrypt to the following protocol versions:

Protocol	Browser	Node.js
Encrypt	v2	v2

Decryption

The library supports decryption of the following protocol versions:

Protocol	Browser	Node.js
Decrypt v0	✅	❌
Decrypt v1	✅	❌
Decrypt v2	✅	✅