Messages are stored on ProtonMail servers in encrypted format. They are also transmitted in encrypted format between their servers and user devices. Messages between ProtonMail users are also transmitted in encrypted form within their secure server network. Protonmail allows you to send encrypted email to non protonmail accounts with a password decryption option. Currently there is minimal support for PGP/GPG PKI; you are given your public key to send to others so they can encrypt messages to you. Full PGP functionality is on their future features list. Protonmail offers free email accounts and paid options. Android and iOS apps available. Protonmail is Open Source. Also accessible on the TOR network: https://protonirockerxow.onion/.
Protonmail offers a VPN service which we have reviewed here.
Mailfence is a paid service hosted in Belgium. It uses a non-US SSL/TLS certificate. They provide end-to-end encryption which makes eavesdropping impossible and renders intercepted data utterly useless, all the encryption/decryption & digital signing occur in the user’s browser. They also offer digital signing capability for authenticating digital messages and documents. Mailfence uses OpenPGP and the paid version has available protocols IMAP, POP, SMTP. With paid versions you can use Mailfence with apps like P≡P, or K9 Mail. Their cryptography application is Open Source and tested in 2014. More about Mailfence design philosophy is here.
Tutanota automatically encrypts all your data on your device. Your emails as well as your contacts stay private. You can easily communicate with any of your friends on end-to-end encrypted. Even subject and attachments as well as all your contacts are encrypted however Tutanota does not use PGP for encryption and they explain why. Tutanota offers free email service with a minimal cost upgrade monthly option. Android and iOS apps available for this service. Tutanota is Open Source.
Mail2Tor is a free anonymous e-mail service to protect your privacy. It is produced independently from The Tor Project. It allows anyone to send and receive email anonymously via webmail or with an email client. You will need to have the Tor browser installed on your computer to access Mail2Tor, or Orbot on your smartphone. You can also use email clients like P≡P over Imap for end to end encryption with others. To access the site, in your Tor browser visit this link: mail2tor2zyjdctd.onion
Shazzle Mail takes an entirely different approach to email. Instead of storing your email on their servers, your devices become the servers. ShazzleMail is a free private email application that turns your smart phone or computers into a mail server, delivering your messages directly to your receiver via an SSL encrypted channel with no server copies. Not even Shazzle gets a copy. You can also send private email to anyone on your contacts. It works with iOS, Android devices and on a PC or Mac laptop/desktop. No apps available for this service.
Invmail is a secure zero-knowledge communications platform, offering services such as e-mail, video/voice calling, messaging capabilities. Data-servers are located in Switzerland, email uses 4096 bit End-to-End Encryption with PKI. Invmail offers free email with the option to upgrade for encrypted voice and messaging with more storage. No apps for this service. It doesn’t appear Invmail has been updated in awhile and they have not responded to our email. Update: September 2017, Invmail website is unresponsive.
Opensource end-to-end encrypted email service, allows for the use of personal encryption keys. Servers are currently located in the United States and will be offering servers elsewhere at some point. SCRYPTmail offers free email accounts with the option to upgrade for more storage and option. We liked the fact you can use a limited amount disposable email aliases with your account for free, more with a service upgrade. No apps or IMAP available for this service yet. Our review. Also accessible on the TOR network: http://scryptmaildniwm6.onion.
CounterMail is a secure and easy to use online email service, designed to provide maximum security and privacy without any unnecessary complexity. Countermail uses OpenPGP, with 4096 bits encryption keys. Their servers do not use any hard drives and instead start from a CD-ROM. This ensures that everything possible is being done to keep your anonymity. Countermail is a paid service only. No apps for this service however you can use imap with apps like P≡P, or K9 Mail. Countermail’s Java Applet is Open Source.