Cover Demo

idle

About

COVER is a demo of a perfect-secrecy steganography algorithm that embeds data in LLM generated text without affecting the distribution of tokens. In addition to preserving the LLM's natural distribution, this method is maximally efficient from the perspective of information theory. This algorithm may be used to transmit data in secret or to mark LLM text with an invisible signature. This implementation uses the tiny SmolLM2-135M language model; a larger model will improve the quality of text.
You can learn more about this algorithm by checking out my post here.

Usage & Notes

Context is the initial seed for the LLM.
For this demo, the length of the message is capped at 64 characters. Longer inputs will not be processed.
Messages shorter than 64 characters will be padded with random bytes. You may see it when decoding.
Use standard english words in the context. Rare text patterns may cause issues with the LLM's tokenizer.
For this demo, the key is generated randomly on encoding. Key and context are copied to the decoding panel automatically.

Example

Context: The most well-known European staple food originally brought from the Americas is

Message: Look for a door marked with a purple lotus, knock twice and call

→ Encode

Context

Message

Key

Result

Output will appear here

← Decode

Context

Message

Key

Result

Output will appear here