Encryption is the process of encoding messages or information in such a way that only authorized parties can read it. Using complex algorithms, the message is transformed into an illegible string of characters without the uniquely generated key. This unique key allows for the message to be transformed back into its original format.
ProtonMail uses encryption to encrypt and decrypt the messages you send and receive. All messages you send to other ProtonMail users are encrypted in this way. Also when you send messages to other services, if you choose to encrypt the message with a password, the same method is used.
When a ProtonMail user sends a message to another ProtonMail user, that message is encrypted, and can only be decrypted with the recipients key. When the recipient gets the message, it would look like this:
Without the appropriate mailbox password the correct key can’t be used, and you will see this:
The same happens if you reset your mailbox password. New keys are generated, and you will see this decryption error on all old messages.
It would be nice if the “See Mailbox Password for more information” would link directly to it 🙂
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I am using the web app for sending e-mails via protonmail. I have entered a mailbox password when I created the mailbox. So, where is this mailbox and how can I be sure that the mailbox password is not stored somewhere at protonmail?
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The mailbox password is used to decrypt your private key and it is not stored on our servers.
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When I am sending a message to another protonmail user with his own domain, how do I know the message is encrypted.
I don’t see any exchange of public key.
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Messages sent to other domains, added on ProtonMail, are treated the same as if sending that message to a ProtonMail user. When you open the message, to the right of the date and time, and the Star option, you can see a padlock, and check how the message is sent.
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Sanding messages from my@customdomain is the same safe level like from user@Protonmail? Are em encrypted too?
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Yes, technically there is no difference between the two.
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I would like to see Protonmail integrate Yubikey, having a tamper proof hardware key to decrypt and sign messages is much more secure
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how do we deal with that if we regular change passwords every 3 months? we can no longer read the old messages?
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If you change your password from your Settings, old messages aren’t encrypted. Messages are encrypted only if you reset the password using the password reset form. You can still decrypt old messages if you manage to remember your old password: https://protonmail.com/support/knowledge-base/restoring-encrypted-mailbox/
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I facing problem “Decryption error
Decryption of this message encryption content failed.
Try again” in all inbox messages, please help me
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This usually happens after you reset your password. When resetting your password, new encryption keys are generated while the previous ones are disabled.
Because of this, your existing messages will become unreadable but you can restore them by providing the old password in the Settings > Keys tab on the web app.
https://protonmail.com/support/knowledge-base/restoring-encrypted-mailbox/.
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