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 weigh the balance 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) 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 set messages to self-destruct, share videos and documents, and participate in group chats of up to 200 users. A caveat? Telegram uses its own custom MTProto encryption rather than a more proven system, and some information-security experts warn that aside from its group chats, Telegram isn't very secure.
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.
European firm Wire Swiss also has a feature-rich encrpyted messenger app on offer, compliant with European data protection laws. Wire (Android, iOS) features end-to-end encryption for text messages, voice and video calls, with support for GIFs, audio and video clips, and sketches, and local and Dropbox file sharing. The app also offers multiplatform cross-device syncing and support for multiple accounts, allowing you to separate personal and work communications. Wire uses its own Proteus encryption protocol inspired by Signal, and its code is open source and subject to external security audits. The mobile and web versions of the app are free, with a premium tier available for businesses.
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.