Virtru - Virtru is your data privacy force field, wrapping and protecting emails and files wherever they're shared. Easy-to-use data security software for business. People also askIs Virtru Hipaa compliant?
Toolsley PGPigeon - Simple but powerful OpenPGP-compatible message encryption webapp.
Paubox - Paubox provides HIPAA compliant email encryption without the hassle of extra steps.
GPGTools - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
Proofpoint Email Encryption - As email is the preferred medium for business communications, preventing confidential information from being leaked in outbound email messages must be a top priority in order to lower the risk of a data breach.
Lockbin - Lockbin is a web application for sending private email messages and files.