"rsync for cloud storage" - Google Drive, Amazon Drive, S3, Dropbox, Backblaze B2, One Drive, Swift, Hubic, Cloudfiles, Google Cloud Storage, Yandex Files
TLS/SSL and crypto library
The Cyber Swiss Army Knife - a web app for encryption, encoding, compression and data analysis
An open source cybersecurity protocol for syncing decentralized graph data.
Set up a personal VPN in the cloud
Scripts to build your own IPsec VPN server, with IPsec/L2TP and Cisco IPsec on Ubuntu, Debian and CentOS