Creating Secure Covert Channels with LLMs over Public Channels

The world of LLMs (Large Language Models) is revolutionising many areas, but there has not been a great deal of work on using them in secure communications. The worry for many is that AI agents will eventually be able to create their own cryptographic cipher that humans would find it almost impossible to break, that they could pass covert messages between themselves that we would not be able to decipher. This could allow AI agents to communicate private information between themselves without humans actually knowing what data was passed. Now a new paper outlines how an LLM framework could be used to hide encrypted covert messages within human-like chats [here]:

It involves using covert public key or symmetric key encrypted communication within human-like text, and which can be used by most of the existing LLM platforms, such as with ChatGPT, Google Gemini, LLaMA and DeepSeek. As an additional feature, it is also post-quantum robust.

The paper outlines the EmbedderLLM function that places specific characters within contextually appropriate words and within specific positions of an LLM-generated response. This type of method has been used the past…