Jingle File Transfer (XEP-0234) describes a very flexible and powerful method for peer-to-peer file transfer with interchangable transports. Unfortunatly only some of those transports can by encrypted (e.g. Jingle In-Band Bytestreams Transport Method (XEP-0261) and none integrate into existing end-to-end encryption schemes. This specification defines an approach to encrypt the actual file before transferring it by using the OMEMO encryption. Note that the encryption can and should happen on the fly.

• https://xmpp.org/extensions/inbox/omemo-filetransfer.html
• https://conversations.im/xeps/omemo-filetransfer.html