Signing messages
Digital signing is a way to ensure the authenticity and integrity of a message. When you sign an email in Private.Ki, you are appending a cryptographic signature generated with your private PGP key.
This allows recipients to verify that the message was indeed from you and not altered in any way.
You can sign encrypted and non-encrypted messages.
Signing is easy, and you don't need to worry about key exchange or anything else, even when sending a message to somebody outside of Private.Ki. As your private PGP key is used for signing, all you have to do is click Sign at the bottom of the compose window:
Sign is activated by default.
Just for clarification, signing a message has nothing to do with your email signature.
The recipient will see that you have sent him a signed message with a valid signature:
Like this, the recipient can be 100% sure that this message is coming from your account and has not been altered during transmission.
If you send a signed message to an external user who does not use PGP, he is still able to see the message. He just won't be able to verify the signature easily. He'll see the message with an attachment that's not human-readable:
The content of the attachment looks like this:
It can only be read and verified with PGP software.