A new open-source tool named Chirp has emerged, enabling the transfer of data, such as text messages, between devices using audio tones. Developed by cybersecurity researcher solst/ICE, this innovative tool maps each character into a specific sound frequency, allowing data to be transmitted through sound waves.
How the Chirp Tool Works
The Chirp application operates by playing audio frequencies that represent characters. Other devices equipped with microphones running the Chirp tool can capture these sounds and translate them back into text. This unique method allows users to exchange messages in a discreet manner, making it a fun and engaging way to communicate.
- Open Source: Available for free on GitHub, making it accessible for developers and tech enthusiasts.
- Real-Time Visualization: Users can see the audio transmission in real-time, enhancing the interactive experience.
- Short-Range Communication: Designed for offline and low-power use cases, although it may not be practical for long-distance communication due to background noise interference.
Despite its potential, the Chirp tool has limitations. It stops listening for new messages while transmitting, meaning any incoming messages during this time are lost. For instance, transmitting a message of 100 words takes approximately 70 seconds, which can be a drawback in fast-paced environments.
Technical Limitations
Chirp currently lacks built-in error correction or redundancy. As a result, the error rate can increase significantly in noisy environments or if the audio output is not sufficiently loud.
Developer solst/ICE mentioned, “Chirp currently has no error correction or redundancy, so the error rate could get impractically high if the background noise is too loud or the speaker sound isn’t high enough.”
Transmission from a computer (left) captured by a smartphone (right)
Source: BleepingComputer
Historical Context and Future Developments
The concept of data transmission via audio signals is not new. Similar methods have been employed in various forms over the last decade. Notably, the idea was demonstrated as an attack called MOSQUITO, created by Israeli researchers in 2018.
The developer plans to explore hypersonic sounds to enable message exchanges using inaudible frequencies, enhancing Chirp’s stealth capabilities. This could make the Chirp tool even more appealing for secure communications.
Privacy Considerations
For those concerned about privacy, the Chirp application is hosted on GitHub pages, ensuring that all functions are processed client-side and never sent to a server. This feature was confirmed during testing, as the online service operated effectively while offline.
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