Sneaky Bits: Advanced Data Smuggling Techniques (ASCII Smuggler Updates)

You are likely aware of ASCII Smuggling via Unicode Tags . It is unique and fascinating because many LLMs inherently interpret these as instructions when delivered as hidden prompt injection, and LLMs can also emit them. Then, a few weeks ago, a post on Hacker News demonstrated how Variant Selectors can be used to smuggle data.

This inspired me to take this further and build Sneaky Bits , where we can encode any Unicode character (or sequence of bytes for that matter) with the usage of only two invisible characters.