Protecting your privacy requires the use of a combination of tools that defend your data from those who may try to intercept it. If you want to prevent eavesdroppers from targetting your communications, it is important that you take the necessary measures to enhance your privacy. One of the solutions that you can consider is RedPhone, a simple, yet effective tool that adds security to your smartphone. RedPhone is one of the solutions originally created by Whisper Systems, a company with a strong focus on privacy that also developed other convenient tools such as TextSecure. RedPhone was initially released on 2010 and it became the first VoIP app to give Android users the possibility secure their calls with end-to-end encryption.
To get more context about RedPhone, it is worth mentioning that Whisper Systems was a start-up created by Stuart Anderson and Matthew Rosenfiled, also known as Moxie Marlinspike. After launching RedPhone, the start-up caught the attention of Twitter. In an attempt to enhance their security, the popular social platform acquired Whisper Systems and hired Anderson and Rosenfield. Twitter released RedPhone as an open source, free app under the general public license version 3 (GPLv3) in 2012. Rosenfiled, aka Marlinspike left Twitter in 2013 to focus on mobile privacy and security. In the same yeat, he founded Open Whisper Systems to continue working on the development of TextSecure and RedPhone.
Since 2013 was also the year in which Edward Snowden revealed information on the surveillance programs carried out by government organizations like the NSA, the relevance of privacy focused apps like RedPhone increased. The Electronic Frontier Foundation (EFF) through its Secure Messaging Scorecard project, gave RedPhone top marks thanks to the secure features and advanced functionality supported by the app. Some of the highlights of RedPhone include encryption of the data during transit and the fact that the data was encrypted in a way that prevents Open Whisper Systems to read it.
In addition, users can verify the identity of whoever they are speaking with and they are also able to to protect previous communications in case future keys are stolen. Another advantage of RedPhone is that the code is open for independent review, making it less likely to be affected by backdoors. Open Whisper Systems has a strong commitment to privacy and the EFF has recognized the quality of the other apps they have created, including Signal, which combines Redphone and TextSecure.
How to make your calls private with RedPhone
It’s time to take a closer look at what RedPhone has to offer. The app works like Skype and Google Voice in the sense that it is a VoIP solution that allows you to make voice calls using a WiFi or data connection. The app works offers cross-platform support so you can enjoy encrypted phone calls on Android or iOS. What makes RedPhone stand apart from regular VoIP apps is that it gives you end-to-end encryption, as long as both you and the other person are using RedPhone, or Signal.
RedPhone is integrated into the standard Android phone dialer, allowing you to make calls to anyone on your contact list. When you use the standard dialer, if the person you are calling has RedPhone on their device, the app will prompt you to protect the call with encryption. The first step to use RedPhone is to install the ap and register your phone. By following the below steps, you will be able to make encrypted VoIP calls using RedPhone on your Android device:
- Download RedPhone and install it. Select install and accept the Terms of service/ App permissions. The download will start automatically. Keep in mind that is only possible to proceed with the installation if you agree to the app permissions.
- For the initial configuration and setup, you need to register the phone, enter the country of your phone (where you bought the SIM card), your phone number and select register. You will get an SMS message containing a six digit code that will allow you to complete the registration. If you don’t receive the SMS, you will have the option to hear an automated 6 digit voice code. Once you have the code, verify the registration.
After installing the app and verifying your phone number, all you need to do in order to make a call is to run the app and choose the person you want to call from your contact list. If the recipient has the app installed on their device, the call will be encrypted and you will see two orange words on the screen. You need to read these words to confirm that the connection is secure. If the words on your screen don’t match with those on the other person’s, it means that the call hasn’t been secured so it is advisable to end the call. RedPhone offers a few basic options that let you check the contacts that use RedPhone or Signal. You can also see the call history, as well as the frequently called contacts. It is also possible to use a dialer to call phone numbers that are not in your contact list. If you call someone who doesn’t have the RedPhone or Signal installed on their device, the app will prompt you to send an unsecured SMS text to invite them to install the app.
RedPhone uses the ZRTP protocol to establish an encrypted VoIP chnanle for the call itself and the data is secured using AES-128 CBC encryption. This protocol is alos used by Silent Circle for their encrypted communication solution. When you make a call using RedPhone or Signal, you can enjoy the advantage of forward secrecy since new keys are generated for every new call, which prevents security issues in case a future key is compromised. RedPhone focuses on mobile devices and it uses audio codecs and buffer algorithms supported by mobile networks. Open Whisper Systems has servers in multiple countries, which helps to offer good speeds and to reduce call latency. The app uses push notificatiosn to make sure that you call is forwarded, even if the person you are trying to contact has their phone switchefd off. It is designed to offer fast and reliable performance, as well as security.
Note
In November 2015, RedPhone and TextSecure were combined into a single solution: Signal, which offers the chance to communicate securely and for free (over the internet) with users around the world. It supports advanced encryption and allows you to create groups and to make calls with high quality.
