Encrypted File Transfer
Sending Encrypted Files
Use the Image/File button 
to choose a file from your system. The file icon and file name appear in the chat-input box.
Note: Photos (.jpg, .png, .gif) are displayed as photos in the receiving chat. Photos placed in zip folders are sent as files.
to choose a file from your system. The file icon and file name appear in the chat-input box.
Receiving Encrypted Files
Encrypted files arrive as "active" messages - you need to click / tap to save the file.
E2EE displays these messages only once and does not save them - the files must by manually saved to the system while the message is onscreen.
How Files are Transferred
When you select a file to transfer, E2EE reads it from your system, converting it to a (Base64) string of text characters in the process.
The file is then run through the AES encryption algorithm to produce an encrypted string ready for transfer.
If the chat partners are in a call, the file message is sent directly device-to-device using peer-to-peer data-channels. If not in a call, the message is sent over-the-server. (This is when private encryption keys are optimal).
When received, the encrypted file is contained within the message and can be decrypted and saved to the system's download folder by click/tap.