PilferShush Jammer

PilferShush Jammer blocks other apps attempting to utilise the microphone without your knowledge. Some apps use hidden processes to record tracking audio in the background that is either generated by nearby beacons, television commercials, streamed music services or websites. This tracking audio is transmitted between 18 kHz and 22 kHz (near ultra high frequency) which is beyond the range of typical human hearing but within the recording range of a typical Android phone.

To block unwanted use of the microphone by hidden app processes, PilferShush Jammer requests use of the hardware microphone from the Android system and holds it. This technique locks up the microphone from any other apps attempting to gain access to it. This technique has been tested only on user apps, not system apps. The Android system should halt PilferShush Jammer from blocking the microphone whenever a phone call is received or made.

When the jamming technique is running and the microphone is locked up, PilferShush Jammer posts a notification to keep the user informed that it is running. Tests have shown that it uses 0% CPU, 0% network and 43.6mb RAM when running for over an hour.

This is an experimental app made as part of research into audio counter-surveillance methods within the Android and IoT world.

It requires RECORD_AUDIO permission so that it may access and lock up the microphone.

It does NOT record or listen to any audio.

It does NOT connect to the internet.

Version 2.0 Active Jammer addition:

Tones can be emitted with a carrier frequency and a drift limit with rate all constrained to NUHF of 18 kHz to 24 kHz depending on the device capabilities. For instance 20000 Hz carrier, drift limit 1000 Hz and rate slow - will output random frequency between 19 kHz and 21 kHz approximately every second.

Version 3.0 Jammers run as a service:

Both the active and passive jammers now run as a (foreground) service that should accurately indicate whether they are running or not. This is dependent on both the Android OS (power management) and any App Managers that may destroy running services.

As this app seeks to block microphone use it is important to NOT dismiss or hide the notification otherwise you may forget it is running.

Also includes a scanner to check user installed apps for NUHF and Audio Content Recognition (ACR) SDKs as well as any services or receivers.

Version 4.0 Redesign

Major overhaul of the design to make information clearer and to simplify typical uses of the app

Notes:

The next release will investigate removing the audible artifacts (popping and clicking) present during the active jamming tones.

White noise output may not be very effective at blocking and is a somewhat annoying sound.

The speaker output may not have enough amplitude to block unwanted NUHF signals - testing will determine.

Source code is available here: https://github.com/kaputnikGo/PilferShushJammer

Research and Project webpage : https://www.cityfreqs.com.au/pilfer.php

PilferShush Jammer阻止其他试图在您不知情的情况下使用麦克风的应用程序。一些应用程序使用隐藏进程在后台记录跟踪音频，这些音频由附近的信标，电视广告，流媒体音乐服务或网站生成。该跟踪音频在18kHz和22kHz之间（接近超高频）发送，这超出了典型的人类听觉范围，但是在典型的Android手机的记录范围内。

为了阻止隐藏应用程序进程不必要地使用麦克风，PilferShush Jammer请求使用Android系统中的硬件麦克风并保留它。此技术可将麦克风与试图访问它的任何其他应用程序锁定。此技术仅在用户应用程序上进行测试，而不是系统应用程序。只要收到或拨打电话，Android系统就应该阻止PilferShush Jammer阻止麦克风。

当干扰技术运行且麦克风被锁定时，PilferShush Jammer会发布通知，通知用户它正在运行。测试表明，在运行一个多小时后，它使用0％CPU，0％网络和43.6mb RAM。

这是一个实验性的应用程序，作为Android和物联网领域内音频反监控方法研究的一部分。

它需要RECORD_AUDIO权限才能访问并锁定麦克风。

它不会录制或收听任何音频。

它不连接到互联网。

版本2.0 Active Jammer另外：

可以以载波频率和漂移极限发射音调，其速率均受限于NUHF为18 kHz至24 kHz，具体取决于设备功能。例如，20000 Hz载波，漂移限制1000 Hz和速率慢 - 将大约每秒输出19 kHz和21 kHz之间的随机频率。

3.0版Jammers作为服务运行：

主动和被动干扰器现在都作为（前台）服务运行，应该准确地指示它们是否正在运行。这取决于Android OS（电源管理）和可能破坏正在运行的服务的任何App Manager。

由于此应用程序试图阻止麦克风使用，因此不要忽略或隐藏通知，否则您可能会忘记它正在运行。

还包括一个扫描仪，用于检查用户安装的NUHF和音频内容识别（ACR）SDK以及任何服务或接收器的应用程序。

版本4.0重新设计

对设计进行重大改革，使信息更清晰，并简化应用程序的典型用途

笔记：

下一个版本将研究在有效干扰音调期间消除可听到的声音（弹出和点击）。

白噪声输出在阻塞时可能不是非常有效并且是有点恼人的声音。

扬声器输出可能没有足够的幅度来阻止不需要的NUHF信号 - 测试将确定。

源代码可在此处获取：https：//github.com/kaputnikGo/PilferShushJammer

研究和项目网页：https：//www.cityfreqs.com.au/pilfer.php