What is a ProtonMail Secure Message?
If one of your contacts is using ProtonMail, they may opt to send you sensitive information through a secure message. A ProtonMail secure message will look like this in your inbox:
Secure messages are emails that are protected with end-to-end encryption and require a message password to read. The message password is something the sender must send to you in advance in order for you to read the message.
Reading and Replying
Clicking on View Secure Message will open the message in your web browser. Once you enter the correct message password, the secure message will be decrypted and you will be able to view the message. You will be able to read, reply and even add attachments. Any replies that you send to the secure message via your web browser will be protected with end-to-end encryption.
Because this is a free service, and in order to combat abuse by spammers, you can only reply to each message a total of 5 times. You can always create a free secure email account to enjoy the benefits of encrypted communication without reply limits and without the need for a message password. Messages between ProtonMail users are automatically encrypted without the need for a message password.
Is this Safe?
ProtonMail uses open source encryption algorithms to secure email communications with end-to-end encryption. This means the messages cannot be intercepted in route, nor can they be accessed by either ProtonMail or any other email provider. The only people with the means to read the messages are the sender and recipient.
ProtonMail’s secure messages are safe to open, and it is safe to click on View Secure Message. You can verify the security of the secure message by making sure you’re connected to the official ProtonMail website (and not a phishing site). The domain name should be protonmail.com.
If you want to be extra secure, you can also verify our SSL certificate. Furthermore, you can also check the secure message’s header information to make sure our DKIM and SPF records match what they should be. If you have any doubts, you can contact our security team at firstname.lastname@example.org.
Encryption made easy
If you also want to send secure messages, you can get a free ProtonMail account. ProtonMail accounts also benefit from automatic end-to-end encryption between ProtonMail accounts, so if you have sensitive communication needs and both parties are using ProtonMail, you can ensure that your communications cannot be intercepted or handed over third parties.