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's 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 among us. 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. A caveat? Telegram's MTProto is custom encryption, rather than employing a more proven system, and you need to opt in to more secure e2e encryption through Secret Chats.
Golden Frog, the maker of the popular Vypr VPN service, has also entered the encrypted messaging field with Cyphr (Android, iOS). The app provides end-to-end encryption, with only a minimal amount of metadata stored in Cyphr's servers, which are only stored temporarily until your message is received. Messages are encrypted with a combination of technologies including AES 256, public and private key pairings, public key verification, and SSL for message delivery. More features are in development, such as desktop apps and multi-device support.
Dust (Android, iOS), formerly Cyber Dust, is another private messaging app that throws in multiple and security and encryption features in an attempt to maintain user privacy. The app uses a combination of AES 128 and RSA 2048 encryption to secure posts and messages, and the app is designed to keep direct messages as much as possible in RAM, rather than your phone's permanent storage. Messages can be set to self-destruct within 24-hours or right after being read. The app is also set not to display user names in a message, and informs the user if a screenshot is taken while in-app.
Pryvate (Android, iOS) is another encrypted messaging app, built with professional and business users in mind. But the app still offers some solid functionality even in its free tier. The Pryvate Now messenger offers RSA 4096 encrypted voice and IM messaging functions, as well as self-destructing messages. Users willing to spring for premium subscriptions get private voice and video calls, secured conference calls, private email, file storage and anti-blocking measures so that you can use the app globally.
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 new video key verification system adds a new layer of security, with users verifying each other with short bursts of encrypted video. 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.