CarrierPony

CarrierPony is a private messenger and secure file transfer app built on real OpenPGP encryption. There is no phone number, no email, and no account. Your identity is an OpenPGP key pair created on your device, and your private key never leaves it.

How it works Every message and every file is end-to-end encrypted with OpenPGP. Content is encrypted on your device and only decrypted on your contact's device. Between the two, a store-and-forward relay carries sealed envelopes: it sees a recipient fingerprint, an opaque message id, a size, and timestamps, and nothing else. No names, no contents, no plaintext.

The relay is a separate, self-hostable component under its own Apache-2.0 license. The client authenticates to it with a challenge-response signature from your key, and a random per-install id is the only device identifier it ever holds.

Pairing happens two ways. In person, one QR scan pairs both phones and marks the contact verified, because the fingerprint travelled physically. Remotely, you send an invite over a channel you already trust, and the invitee's app fetches your key from the relay and refuses to add it unless it hashes to the fingerprint the invite carried. Either way you can compare a safety number to be certain no one is in the middle.