Picocrypt -

The entire source code (written in Go) is ~2,000 lines. A single developer (Evan Su) maintains it, and the code is written to be read by humans, not just compilers. This means security researchers can fully audit the program in an afternoon—not a year.

Picocrypt: Small. Simple. Secure. No strings attached. picocrypt

In an era of bloated "security suites" that spy on you to "protect" you, Picocrypt is a breath of fresh air. It asks for nothing and gives you back control of your data. As its documentation proudly states: "If it doesn't have a GUI, is hard to use, or is closed-source, it's not Picocrypt." The entire source code (written in Go) is ~2,000 lines