In the post-Snowden age, we've become much more aware about online privacy and the dangers of digital snooping and identity and data theft. Even as government agencies and tech companies try to hash out the interplay between privacy and public security, app makers have been busy creating encrypted messaging tools, or adding end-to-end encryption to existing messaging services to meet the demands of users who have become more concerned about online privacy. Check out some of the best mobile encrypted messaging apps available right now for Android and iOS devices.
Open Whisper Systems' Signal (Android, iOS) is a fantastic messaging solution for security-conscious mobile users. It is a free all-in-one messaging and voice-call solution that uses end-to-end encryption. You can send text messages, voice calls, group messages, media and attachments to your phone contacts, all without having to mess with PIN codes or special login credentials. Messages can also be set to self-destruct after a certain amount of time. A newly added Chrome browser plugin lets you use Signal from your desktop as well.
Ease of use and strong, open-source, regularly audited encryption makes Signal a favorite of the security-conscious, with accolades from Edward Snowden and other privacy advocates. User-friendliness without compromising on security makes Signal a fantastic option for users looking for an encrypted messaging and calling app.
Silent Circle is a trusted provider of secure-communications software and hardware, such as the Blackphone, and it has also developed its own secure mobile-messaging platform. Silent Phone (Android, iOS) provides encrypted video and voice calls, as well as encrypted, self-destructing messaging and file transfers. Encryption keys are held by subscribers themselves, not by Silent Circle, so while your encrypted messages may pass through Silent Circle's network, the company can't read your data.
Telegram Messenger (Android, iOS) is another secure-messaging app aimed squarely at the security-conscious user, but it also doesn't want to leave out less tech-savvy users. Once you've linked a Telegram account to your phone number, you can use the app to send fast, encrypted chat messaging over the cloud, with client-server encryption for standard chats. A Secure Chat mode provides end-to-end encryption so that only you and your intended recipient can read it. You can even set messages to self-destruct. You can share videos, documents and participate in group chats of up to 200 users. One hundred percent free and ad-free, Telegram is another good option for both tech-savvy and everyday users looking for a secure-messaging solution.
Wickr Me (Android, iOS) is a free end-to-end encrypted-messaging app that allows users to send private, self-destructing messages (text, photo, video, and voice) to other Wickr contacts. The app takes user privacy seriously, using strong encryption and deleting metadata such as geotags and message times, and users can configure how long it takes for messages to self-destruct. A Secure Shredder included in the app even allows you to securely erase attached files, messages and other data to prevent recovery. The app's security is a point of pride for Wickr; there's even a $100,000 bug-bounty program for anyone who gets in touch with the company to point out a security flaw.
Silence is a messaging app that uses the same encryption system as Signal to send and receive encrypted SMS and MMS messages. Silence requires no extra signups or logins for you and your contacts to use — just the app itself. Messages are also encrypted locally, with a passphrase needed to open and read messages, providing an additional level of security if you lose your device.
WhatsApp (Android, iOS) has long been working towards adding end-to-end encryption to its instant-messaging app, partnering with Open Whisper Systems in 2014 to add the same encryption methods used in Signal. A year ago, WhatsApp and Open Whisper announced that all WhatsApp communications on all platforms from then on would be protected by end-to-end encryption, complete with a security-verification code that you can compare with a contact to ensure that your conversation is encrypted. Combined with WhatsApp's ubiquity, ease of use and the ability to send voice messages, photos, and video messages, and conduct group chats, this makes for a robust and, now, encrypted mobile-messaging app.
The near-ubiquitous Facebook Messenger may not be the first app you think of when it comes to encrypted messaging, but the mobile versions of the app (Android, iOS) do include end-to-end encrypted communication options in the form of Secret Conversations. Based on the same encryption system used in Signal, Secret Conversations requires users to opt-in to the feature, and allows them to send and receive encrypted text, pictures, and stickers to and from a single mobile device, with the option for time-limited self-destructing messages ala Snapchat. That said, Facebook Messenger is still vulnerable to being screen-grabbed, and the opt-in and single device limitations can be an issue.