Let's Encrypt - Let’s Encrypt is a free, automated, and open certificate authority brought to you by the Internet Security Research Group (ISRG).
Microsoft BitLocker - BitLocker is a full disk encryption feature included with Windows Vista and later.
GeoTrust - Guarantee online customer security with SSL certificates from GeoTrust. Purchase in bulk, manage multiple certificates & become your own Certificate Authority.
Paubox - Paubox provides HIPAA compliant email encryption without the hassle of extra steps.