New Chirp tool uses audio tones to transfer data between devices

A new open-source tool named ‘Chirp’ transmits data, such as text messages, between computers (and smartphones) through different audio tones.

The tool, developed by cybersecurity researcher solst/ICE, maps each character into a specific sound frequency and plays it along with real-time visualization.

Other microphone-equipped computers running Chirp may capture the sound and translate the message back into text.

The project allows users to “sneak” messages between devices in a fun way, and it’s available both online and as a standalone app available for free through GitHub.

Although it’s not overly practical for most real-world applications due to background noise interference, it could still prove helpful in short-range, offline, and low-power use cases.

One practical limitation of Chirp is that it stops listening for messages when transmitting, so anything received during that time is essentially lost.

When considering that a message consisting of 100 words takes roughly 70 seconds to transmit, this can be a problem in some cases.

The developer also told us that 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.

Old concept, fun new approach

The concept of transmitting data via a speaker-microphone configuration isn’t new, with numerous similar implementations dating as far back as a decade ago.

The idea itself has also been demonstrated as an attack dubbed ‘MOSQUITO,’ developed by Israeli researchers in 2018.

Chirp.io, owned by Sonos since 2020, did something similar, facilitating seamless device-to-device communication without traditional wireless connections.

solst/ICE told BleepingComputer that the idea to develop an open-source Chirp tool came after watching a demo of two LLMs talking to each other using ggwave-generated audio signals.

Developed by Georgi Gerganov, ggwave is a compact data-over-sound library that facilitates the transmission and reception of short data messages through sound waves.

solst/ICE informed us that the next step is to experiment with hypersonic sounds to allow message exchanges using inaudible frequencies. This will make Chirp even more stealthy and more fun to play with.

For those wanting to play with the online Chirp application and are worried about privacy, the developer told BleepingComputer that the application is hosted on GitHub pages, and all functions happen on the client side and are never sent to a server.

Our tests confirmed this, as the online service works as expected when offline.