A fun mashup of networking, file IO and cryptography using Go's standard package library. There'll be cipher streams for files and TCP connections, hybrid encryption between web services using AES and RSA, and HMAC signatures for tamper-proofing. All backed up with working code. Aside from the technical content we'll explore the benefits of putting security at the heart of application design, knowing as little as necessary about our users to service their needs without compromising their privacy.