Secure email makes it possible for users to send, receive and store encrypted messages. Users should consider encryption standards, storage mediums and limits, and the location of a service. Determine whether these leading providers meet your privacy and security requirements by signing up for a free service tier or trial period.
Runbox
Privacy rights are protected by the constitution of Norway, where Runbox is located. This service provides end-to-end encryption using PGP and supports IMAP, POP, SMTP, FTP and DAV support for third-party clients. Runbox relies exclusively on clean and renewable hydropower.
This service maintains dedicated mobile apps and makes it easy to import emails. After a 30-day trial period, customers can obtain 1 GB of email storage and 100 MB of file storage for $19.95 (14,95 EUR) per year. More storage and email hosting options range from $34.95 up to $79.95 (29,95 to 69,95 EUR).
CounterMail
CounterMail is a service based in Sweden which stands out for its exceptional security measures. Users can rely on end-to-end Open PGP encryption with with 4,096 keys and no-log, diskless servers. Email headers are anonymized, senders‘ IP addresses are stripped and all emails and attachments are encrypted at rest.
CounterMail protects against identity leaks and Man-In-The-Middle attacks with AES-CBC and RSA encryption on top of SSL. Customers have the option to use a physical USB key and a password manager for increased security. This service starts at about $4.83 per month with a 6-month plan with 1000 MB of storage and goes down to $3.29 per month with a two-year plan with 2000 MB of storage.
Mailfence
This Belgian secure email service provides AES-256 bit security, OpenPGP key management and digital signing. Paid users obtain support for POP, IMAP and SMTP, and this service also supports WebDAV, CalDEV and CardDEV. It is also possible to use Mailfence to send messages through another email address.
Mailfence allots free users 500 MB of email storage and 500 MB of document storage as well as limited access to integrated features. Entry-level membership with 5GB of email storage, 12GB of document storage and upgraded options starts at 2,50 EUR (about $2.82) per month. There is a mobile site, but no dedicated mobile applications are currently available. This service may log browser versions, countries, email addresses, IP addresses, message-IDs, subjects and timestamps.
Tutanota
Tutanota is a German secure email service that relies on AES and RSA to encrypt subject lines, headers and the body of email messages in addition to attachments and metadata. This service relies on AES-128 bit encryption, which is less secure than 256-bit encryption. IP addresses are stripped from messages and emails are encrypted at rest.
The ability to search for messages is limited, as are options for importing existing emails. No PGP, IMAP, POP or SMTP support is available, but dedicated Android and iOS applications are available. This option is free to use with up to 1 GB of storage, and the premium service starts at 12 EUR (about $13.54).
Posteo
If security and sustainability are primary concerns, a user should consider Posteo. This service encrypts subject lines, headers and the body of messages as well as attachments and metadata. Two-factor authentication is available, and users can encrypt information with a single click.
IMAP and POP3 support make it possible to use Posteo with third-party email clients. End-to-end encryption is available in the webmail interface with the browser add-on Mailvelope. Open an account with 2 GB of storage for 1 EUR (about $1.13) per month. As of 2019, this service does not maintain IP logs except in the case of surveillance warrants as required by the German Constitutional Court.
Mailbox.org
Mailbox.org is another affordable and sustainably-powered secure email service based in Germany. All emails are stored encrypted at rest in two separate data centers. Mailbox.org offers full PGP encryption and key management and supports POP, IMPA, SMTP and DAV. A full migration service and spam and virus filters are also available.
Try this service with a 30-day free trial. Paid accounts start at 1 EUR (about $1.13) per month with 2 GB of mail storage and 100 MB of cloud storage. This German service is subject to the same government requirements as Posteo.
ProtonMail
ProtonMail is a popular secure email provider based in Switzerland. This service uses PGP, but does not encrypt headers, metadata or subject lines. IP addresses are stripped and messages and attachments are encrypted at rest.
It is easy to import contacts and emails into ProtonMail. The free tier of this service provides 500MB of storage. The Plus tier starts at $5 (about 4.43 EUR) a month or $4 (3.54 EUR) billed yearly and has 5 GB of storage, while the Visionary tier is $30 (26.58 EUR) a month or $24 (21.27 EUR) billed yearly with 20 GB of storage and 10 custom domains.
Selecting a Secure Communications Solution
Be sure to factor in the location of physical data storage when choosing a secure email service. Users should also consider whether end-to-end encryption is available. These elements directly affect the security of communications. Ease of use is also an important consideration.
Almost every free mainstream email client compromises user privacy by monetizing data. The secure services on this list work to maintain user privacy. Round out a threat model by using a secure browser for webmail clients and a virtual private network. Learn more about VPNs and ways to protect your privacy and increase the security of computers and mobile devices.