Similar to Bitmessage

KeePassX

KeePassXC

KGPG

Kontact

LibreSSL

Linux Unified Key Setup

Microsoft Outlook

NaCl (software)

Network Security Services

OMEMO

OpenSSH

OpenSSL

Openswan

OpenVPN

Ophcrack

Peer-to-peer

Pretty Good Privacy

ProVerif

PuTTY

Qubes OS

Secure Shell

Security Support Provider Interface

Silent Circle (software)

SSLeay

StrongSwan