ProtonMail 3.1 Review (2016)

ProtonMail is a privacy-focused e-mail service that is fully open source and free to use. Read my Proton Mail review for more details!
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Review of:

Reviewed by:
On March 15, 2016
Last modified:October 14, 2016


When I first reviewed ProtonMail over a year ago, it was very much a fledgling service still in its alpha phase of development. Even back then, I thought it had great promise as long as its limitations were fully understood. Since then ProtonMail has introduced many new features, including premium accounts, the ability to send encrypted emails to non-ProtonMail users, mobile apps, and (perhaps most importantly of all) it has become fully open source.

Many aspects of the service, however, have not changed, so rather than reinventing the wheel, this article is an expanded and revised version of my original review.


I Liked

  • Much more secure than regular email
  • Emails are not spied on for advertising purposes
  • Easy to use and looks great
  • Completely open source
  • Can send encrypted emails to non-users
  • Self-destruct emails
  • Genuinely useful premium options (including own domains)

I wasn’t so sure about

  • Nowhere near as secure as “proper” PGP email
  • Benefits of being based in Switzerland are debatable
  • Mobile apps still not available in Apple and Play Stores
  • SMS verification at registration (can be avoided by upgrading to a premium account)

I hated

  • Misrepresentation of the service as “anonymous”. It’s not
  • Unspectacular Email Privacy Tester results
  • Using ProtonMail will attract attention (not its fault, per se, but worth noting)

What is ProtonMail?

ProtonMail is privacy-focused webmail service designed to provide the functionality and ease-of-use of services such as Gmail, but which is secure and does not spy on its users’ communications in order to flog them stuff, or to hand over to the NSA.

Video promotion for the original IndieGoGo campaign

It has been developed by a team of research students from MIT and Harvard, headed by Harvard PhD candidate and CERN researcher Andy Yen, and was initially crowdfunded by a wildly successful IndieGoGo campaign.

Waiting List

Interest in ProtonMail has been high, and it has struggled to accommodate new users, resulting in a a waiting list before accounts are activated. This rather frustrating issue has many opting for the (also very good) Tutanota instead, which has no such waiting list.

Fortunately, waiting times have now dropped from the 8 months (!) that it took for me to receive an invitation over a year ago, to around 2 weeks (according to anecdotal reports). This may, however, remain an issue for the more impatient of you out there.

Update: Just 2 days after publishing this review, ProtonMail has opened up subscription to all.

Pricing and Plans

One of the most important developments is the introduction of premium plans. The very useable free tier still exists (and ProtonMail has promised it will always continue to exist), but premium plans add some very useful features, such as custom domains and web addresses, plus increased storage and messages per day.

The ProtonMail Plus plan starts at $5 per month (or $4 per month if paid yearly), but can be customised further. The ProtonMail Visionary plan starts at $30 per month, and is clearly intended for businesses.

ProtonMail pricing 2

Custom Domains – if you have your own domain name, you can use this to send and receive encrypted messages using your ProtonMail account (for example at

ProtonMail Addresses – this is the number of or addresses you can have. ProtonMail plans to add sorting features for these in a future release.

New keys are generated for each new custom domain or ProtonMail alias.

For casual users the free service will likely be more than sufficient, but for power users the premium extras make a welcome addition, and are an excellent way to help fund the service (remember, ProtonMail makes no money through advertising or selling your data to advertisers!).


  • End-to-end encrypted emails
  • Can send encrypted emails to non-ProtonMail users
  • Self-destruct emails
  • Improved web interface with drag and drop messages, contacts manager, authentication logs, and more
  • Apps for Android and iOS
  • Based in Switzerland (more on this later)
  • Completely open source
  • Public key export (to send to other PGP users and to verify messages manually)


That ProtonMail operates out of Switzerland is a big draw for many users, as Switzerland is outside US and EU jurisdiction, and has a reputation for very strong privacy laws. Surveillance directives must be obtained through the courts and with no gaging powers targets must be notified, technical interception of electronic communications is only permitted with regards to ISP’s and not “mere” Internet application providers (such as email services), etc.

Whether this reputation is entirely justified, however, is not so clear cut. It is often said, for example, that Swiss authorities have no interest in cooperating with the US and its allies, but as US tax evaders stashing their wealth in Swiss bank accounts found out in 2013, this is not always the case. Victor Vital, a trial lawyer at Barnes & Thornburg, told Wired that,

People seem to think that data privacy laws in Europe or in foreign countries pose problems or would be a roadblock, but that’s just not the case, because under those treaties the countries obligate themselves to cooperate as broadly and as much as possible.

Even more worrying is that powerful new surveillance laws (the Nachrichtendienstgesetzt (NDG) the “BÜPF) are being pushed for by the Swiss government in the wake of last year’s terroriust attacks in Paris, which will greatly expand the State’s surveillance powers.

Thanks to the Swiss system of democracy, the NDG is on hold until a national referendum is held on it in June, and ProtonMail was notable for campaigning to raise the 70,000 signatures required to bring this about. The BÜPF is “up for a vote in the Parliament’s spring session, but may be revised or delayed.”

I think it fair, therefore, to say that the situation is very much in the air, although ProtonMail claims it will not be affected by the NDG law, even if it is passed by the referendum.


ProtonMail accounts are protected by two passwords, the first of which is used to authenticate the user and retrieve the correct account (and which ProtonMail keeps a copy of), and the second is kept only by the user, and is used to decrypt their mailbox. As Micah Lee, a technologist at the Intercept who focuses on privacy and cryptography notes,

It’s actually really nice that they have two sets of passwords. The login password gets sent to the server, and that’s how you prove that your username is actually yours. And the second is the mailbox password, which never gets sent to ProtonMail’s server. The second password runs in your browser and decrypts your messages there.

Mail is stored encrypted on ProtonMail’s servers, so the ProtonMail staff has no access to them, and these servers themselves “utilize fully encrypted hard disks with multiple password layers so data security is preserved even if our hardware is seized.”

All messages sent between ProtonMail members are encrypted.  Messages to non-ProtonMail members can also be sent encrypted, or can be sent unencrypted via regular plaintext email.

According to ProtonMail, no metadata is kept and it does not log the IPs users’ connect from (although there is technically nothing preventing it from doing this). As ProtonMail also points out, because messages are encrypted, there is no way for it to scan them in order to deliver targeted advertising.

Update: A major issue that I missed while initially writing this review (due the fact that I used my existing ProtonMail account) is that ProtonMail now asks for human verification (often via SMS) while registering for a new account.

This is in many ways a quite understandable (and possibly necessary) precaution to prevent the service being abused by spammers and spambots, but it does completely undermine any notions of anonymity. Users not happy with providing an email or phone number can avoid doing so by upgrading to a premium account (which can be paid for anonymously using Bitcoins).

Technical security

ProtonMail uses end-to-end encryption for encrypted messages, using “secure implementations” of the open source AES, RSA, and OpenPGP libraries (TLS 1.0, AES-128 CBC, DHE RSA handshake, and SHA3 hash authentication).

This is ok, although TL 1.0 is somewhat outdated, and most experts consider AES-256 to be more secure than AES-128 (this is open to debate, however, as AES-128 has a stronger key schedule).


The SSL certificates are now signed by QuoVadis Trustlink Schweiz AG,

Advanced features of our new certificate include Extended Validation (EV), 4096-bit RSA, SHA-256 hash, and Certificate Transparency (CT). Together with QuoVadis, we will continue to stay on the cutting edge of SSL certificate technology to ensure the highest level of security for ProtonMail users.

A big issue we had with ProtonMail was that its software was not fully open source, but this has all changed, and it is now 100 percent open source. Unlike much open source code, however, ProtonMail’s has been extensively audited by a team of well-known and respected cryptographers who volunteered (for no payment) to oversee the project, looking for backdoors and other nastinesses.

So far so good, but the news is not all so rosy.  As Yael Grauer from Wired explains,

One of the big issues is that it isn’t easy to know whether a message sent to another ProtonMail user is being encrypted to the recipient’s correct public key, which is stored on ProtonMail’s keyserver. For example, if Alice sends Bob a message encrypted to his public key, it’s harder for anyone else to read the message. But since ProtonMail distributes the encryption keys to users, it has the technical ability to give Alice its own keys in addition to Bob’s, thus encrypting the messages in a way that would allow it to eavesdrop.”

This is a weakness shared by Apple iMessage, but which has been solved in apps such as Signal by verifying the public encryption keys.

Another glaring problem is that all cryptography is performed within users’ browsers using JavaScript. This essential in order for encryption to be performed end-to-end (rather than being performed by ProtonMail, with ProtonMail holding the private keys), but JavaScript cryptography is inherently very insecure.

This is a problem that should not affect users of the mobile apps, as long as they remember to only access their ProtonMail accounts using the mobile app, as these do not use JavaScript for their cryptography.

When sending an encrypted email to non-users, the content of the email and any attachments are encrypted. Normal email metadata information is included in the header, however, including the sender’s email address, the time the email was received, and the Subject title (which can, of course, be very revealing).

The takeaway here is that ProtonMail is much more secure than “regular” webmail services, will be resistant to blanket surveillance (although it is 100 percent definite that the NSA and other security services will monitor ProtonMail accounts vigorously), and that ProtonMail will not spy on your email in order to sell your data to advertisers.

ProtonMail’s claim that it provides “anonymous email” should be taken with a healthy pinch of salt, however, and it should be clearly understood that using this service is nowhere near as secure as using a standalone email client with a good PGP plugin installed (see our tutorial on using Gpg4win), or even a browser with an add-on such as Mailvelope installed.

ProtonMail in use

Signing in

Signing in requires you to enter two passwords…

ProtonMail sign-in 1

Your account password, which is known by ProtonMail…

ProtonMail sign-in 2

… and your mailbox password, which should be known only by yourself

ProtonMail wen interface

Anyone familiar with webmail services will feel instantly at home with ProtonMail. The new 2.0 interface looks good, and works smoothly

ProronMail send email

Messages sent to other ProtonMail users are automatically encrypted, while messages sent to non-ProtonMail users can optionally be encrypted. Such messages will expire (auto-destruct) in 28 days, or earlier should you choose

ProtonMail receive secure email

The recipient receives a link to the encrypted message (plus the hint, if used). Note that this message will expire after one hour, but also note that no metadata is hidden

ProtonMail recive secure email 2

… and when they enter the password..

ProtonMail recive secure email 3

…they can read the message

ProtonMail expire

If a message has expired then the link becomes dead

ProtonMail mobile web

Although no mobile apps are currently available (still in Beta at the time of writing), ProtonMail’s responsive website design means that it looks great in a mobile web browser

Other Platforms

Update March 2016: The web interface is, of course available on all platforms via your regular browser. ProtonMail has now also released apps for Android and iOS.

ProtonMail Android appThe Android app looks smart and works well

Email Privacy Tester results

I tested ProtonMail using the Email Privacy Tester tool developed by Mike Cardwell.

ProtonMail test results

These are the same results I achieved when I tested almost a year ago, and were not as good as those from Tutanota even back then


I Liked

  • Much more secure than regular email
  • Emails are not spied on for advertising purposes
  • Easy to use and looks great
  • Completely open source
  • Can send encrypted emails to non-users
  • Self-destruct emails
  • Genuinely useful premium options (including own domains)

I wasn’t so sure about

  • Nowhere near as secure as “proper” PGP email
  • Benefits of being based in Switzerland are debatable
  • Mobile apps still not available in Apple and Play Stores
  • SMS verification at registration (can be avoided by upgrading to a premium account)

I hated

  • Misrepresentation of the service as “anonymous”. It’s not
  • Unspectacular Email Privacy Tester results
  • Using ProtonMail will attract attention (not its fault, per se, but worth noting)

It is often argued that when it comes to secure communication, the outdated email system is completely broken, and ProtonMail is not going to change that. Furthermore, any webmail system that implements encryption within the browser (using JavaScript) is also likely fundamentally insecure. As ProtonMail itself admits on its Threat Model page,

NOT RECOMMENDED: Edward Snowden – If you are Edward Snowden, or the next Edward Snowden, and have a life and death situation that requires privacy, we would not recommend using ProtonMail. For extremely sensitive situations, it is simply not a good idea to use email as a medium for communication.”

However, ProtonMail is a very easy to use webmail service (on par with Gmail and suchlike) that is much more secure than most such webmail services, and which will not (cannot) spy on all your correspondence in order to target advertising (as Google, Microsoft, Apple, et al. do).

Furthermore, while it is unlikely to be secure against targeted NSA attacks (and users should be aware that the NSA will likely target users of the service), ProtonMail for most purposes (including investigations by national law enforcement bodies) provides a high level of privacy, and being based in Switzerland, it should be resilient against many legal forms of attack.

In terms of usability, ProtonMail has added a ton of features since it first started that make it very viable alternative to mainstream webmail services, and the move to fully open source is very welcome.

In short, as long as it’s (considerable) limitations are recognized, using ProtonMail can be a positive step towards improving your privacy and resisting blanket government surveillance. Just don’t expect it to provide genuine anonymity, or to protect you if you are up to anything very illegal.

Douglas Crawford I am a freelance writer, technology enthusiast, and lover of life who enjoys spinning words and sharing knowledge for a living. Find me on Google+

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25 responses to “ProtonMail 3.1 Review (2016)

  1. how does the encryption key get transmitted to the non protonmail addressee of a encrypted email? Must this be pre-coordindated or inferred from the hint?

    1. Hi alan,

      Yes. When a ProtonMail member sends an encrypted email to a non-ProtonMail user, the password must be pre-arranged or inferred from the hint based on your shared knowledge (e.g. Where we met up that time when it was raining). The safest way to pre-arrange a password is in-person, although encrypted messaging apps such Pidgin + OTR or Signal are a good second-best.

      To contact a stranger securely, with whom this is not possible, you should instead use PGP. This allows you to send a secure message using their public key (which is often stored on a publicly accessible key server). ProtonMail does not currently support PGP, although this is a feature that should be coming soon.

    2. How secure is Protons servers,…. with yahoo servers and other major servers being hacked years before anyone knew it. There have been hacker programs to hack yahoo for years.

      1. Hi Will,

        It is my understanding that ProtonMail’s servers are much more secure than Yahoo’s ever were. Given that ProtonMail is based in Switzerland, however, does mean that the country’s severe new data retention laws are probably of major concern.

    1. Hi bakhtiyor,

      Yes, but that is irrelevant, as the signal is end-to-end encrypted and decypted using the open source frontend client. That the back-end is not open source does not matter, as at no time can it read the encrypted emails.

  2. Yes, you can have completely anonymous accounts if that is something useful for you.
    Set up through tor or a good VPN. Pick a randomized username.

    Use throwaway cell phone or just use Capcha for verification (I utterly understand why they do this — spam reduction).


    Additional feature not mentioned previously. They added filters recently. Whew! Now much more useful of an email service.

  3. Hello Douglas – Thank you for your kind response. Now that you’ve mentioned no waiting period, I think I may have made an error with my original application which wasn’t flagged up when I submitted it.
    Kind Regards.

  4. Hi, can anyone inform me whether there’s still a long waiting time?
    I subscribed almost a month ago and have not received any notification confirming my application. As a general rule I would’ve expected to be acknowledged. Surely with the basic systems Emails would generate a response and it leaves me wondering about the legitimacy of what they purport to offer.
    Any advice barring subscription to another service would be helpful as I’d given some thought regarding StartMail but decided to try this as it was basic, with the option of upgrading. Thank you.

    1. Hi connie,

      I think your application must have got lost in the system. There is now no longer a waiting list for ProtonMail, and you can signup immediately.

    1. Hi Some reader,

      This true, but ProtonMail might still require SMS verification (for free accounts).

  5. “Thanks to the Swiss system of democracy, the NDG is on hold until a national referendum is held on it in June, and ProtonMail was notable for campaigning to raise the 70,000 signatures required to bring this about. The BÜPF is “up for a vote in the Parliament’s spring session, but may be revised or delayed.”

    The people’s vote will be held at 25th of September 2016.

    1. Hi John,

      Thanks for letting us know. I am unable to find confirmation about this (probably because I am limited to searching for English sources). If you can provide link, I would be very greatful, and will upodate the article accortdingly.

    1. Hi mesophl,

      It is well established that the NSA monitors users of secure internet services. I therefore think fair to assume that it monitors users of such a high-profile privacy-oriented email service as ProtonMail.

  6. This service is BS. They require you to enter your cell phone to receive an SMS message. Kind of defeats the purpose!

    1. Hi Jimmy,

      Hmm. I performed this review using my existing account. The SMS requirement is new, and I agree – it definitely undermines any notions of anonymity.

        1. Hi Konstantin,

          Yeah, I know. I concentrated on SMS verification because this presents a much serious threat to privacy than having to complete a Captcha.

    2. If you are worried about this, get a cheap throwaway phone. You can buy one for about $25. Pay for it with a card that you bought with cash. I have a smart phone and a “burner.” The smart phone for my friends and the burner for routine business dealings.

  7. thanks for the answer. another question – Proton Mile still encrypts only the body of the letter, but not the title or investments, or now it also encrypts them? In tutanute, as I understand it, it is encrypted and header and attachments, and the body? right?

    1. Hi Ant,

      ProtonMail now also encrypts attachments, but the Subject title is still visible (I just checked this). In Tutanota the subject title is hidden.

    1. Hi Ant,

      Your comment has caused me to re-examine the issue, and it seems that I have made a slight error (now corrected). Both ProtonMail and Tutanota allow you to send non-users encrypted emails (in Tutanota this is enabled by default, in ProtonMail you must select the option.) In both cases the sender’s email address and the time the email was received are included in the header information, but the subject line (plus all content and attachments) is hidden.

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