I'd like to explain how easy it really is to send secure encrypted messages. But I have to explain how this works, because the basic knowledge is necessary, otherwise you can not understand that.
How does encryption work?
As a rule any file or text can be encrypted. This is done with the help of a "private" and a "public key". Both are usually created by using a password or a string and converting it to a specific value.
There are also different methods for how to do that. But that is not so important for my contribution and leads to confusion mostly. In practice then, for example, "123" becomes "2wAPySWF2 @ + $ ZmKr". But the higher you do encryption, 123 can also be a drawing sequence with 10.000 or more characters.
At PGP (Pretty Good Privacy) There is, as usual, just the "public" and the "private" key is calculated. These strings are in turn the password to encode files (that's what you do with the "public" key or decode what you do with the "private" key.) So if you want to encrypt a date that you just open yourself can. If you only use your own key pair. But if you want to encrypt a file, so that someone else has access to it WITHOUT having his own "private" key, then you simply use the public key of the recipient for it. You can also encrypt files for several people at the same time. One should never forget his own public keys, because one can encrypt files only for someone else, but then has no access to it.
As far as comprehensible? It sounds more complicated than it actually is. But only with this knowledge one understands and can implement that.
I'm sorry, but this information is really important to understand how it works. The principle is always the same, regardless of whether one saves text, files or data which are then transferred.
Public key (for encryption) and
Private key (to decrypt)
There is always the "public" key with the encrypted and the "private" and only with this the file can be made readable afterwards (decrypted)!
As the name implies, the public key is not a secret, nor does it have to be, because it allows you to encrypt files but can not decrypt them anymore.
My "public PGP key" is:
--BEGIN PGP PUBLIC KEY BLOCK--
QFhaCCtEBBUIAgoDFgIBAhkBAhsDAh4BAAA6wg // bxDQ3dAHLQuLMacgKwG0
V5Xzz0B / fPhSQVyZjMEkdWVoBALLerRBmx + qXAqV97oRcjxTkvJepnYXSdGW
Pm1liGK + BFkQ0XXcdUEDlbDVkULWhmKSzTjLBy7fABEBAAHCwV8EGAEIABMF
AlbZYNEJEHlyQFhaCCtEAhsMAACfkg / 7BHSOSRdiiVuzND4dqN2PRDdelzlp
--END PGP PUBLIC KEY BLOCK--
This string was created from a password that I converted with 4096-bit. As briefly described in the above example. It is safe that this key is accessible because it does not suggest my "private" key.
Encrypt one now Text like "123", then come out:
--BEGIN PGP MESSAGE--
sHc0eWQoBCpxxP6fcyVP9aQEaMV + + reZcQYFXqDAj qQPg4yKeZuTvTMn / KQQ
--END PGP MESSAGE--
So if you want to send an encrypted email, you also need the "public key" of the recipient. This is the only way to encrypt a text or a file and the recipient can then open it again with his "private key".
It is not the "email" encrypted itself, because this file (the email itself is quasi the envelope) must be read yes. So the recipient must be naturally readable, as for a letter envelope, for everyone. But it explains the contents as in the above example "encrypted" for themselves and the recipients. It is important that one should know that all what one writes therefore in the subject of the e-mail and also sender and receiver are visible to third parties.
So if you betray all the content in the subject, then you do not need to encrypt the content anymore!
There are two simple TIPS and examples of encrypted communication by e-mail.
Mailvelope and TutaNota.
Mailvelope is a PGP encryption tool that can be conveniently integrated into any Internet browser and is free. Thus, you can create your own key pairs, import and save public keys of others and encrypt or decrypt texts of emails directly. This is handy if you use any webmail service. It does not matter which one!
TutaNota is a free email service that encrypts and sends messages to others WITHOUT encrypting them. This happens by simply dropping the message encrypted when it is sent to TutaNota. The recipient only receives a notification that an encrypted message has been provided for him and then, in order to open them, he has to enter a password that sender and recipient have previously shared (NOT by EMAIL!). That can always be the same password and even if it is not smart, would also "123" work.
Or you can combine both. Encrypt the content of the message via Mailvelope with PGP and then send it encrypted to the recipient 🙂
I hope that this information is helpful and I am also happy about your encrypted message via email! You can reach me using my public PGP key and / or my email address: firstname.lastname@example.org