I like the wormhole-william[0] Go implementation of "Magic Wormhole" protocol on the CLI. There's a couple of compatible Android apps[1][2] in the F-Droid store and Rydmport[3] for your GUI loving friends.

[0](https://github.com/psanford/wormhole-william)

[1](https://f-droid.org/en/packages/com.pavelsof.wormhole/)

[2](https://f-droid.org/en/packages/com.leastauthority.destiny/)

[3](https://github.com/Jacalz/rymdport)