Three basic features of secure communication include:
- Identity, ie to control the identity of the sender (you) and the receiver and protect it against identity theft
- Privacy, ie to control the information and protect it against information theft
- Integrity, ie to control the system and protect it against modification from others (“hacking”)
The OpenPGP standard gives you “pretty good privacy”, while leaving responsibility for checking “identity” and “integrity” up to the user.
On Linux you can use the the OpenPGP standard by installing the pgpgpg (“Pretty Good Privacy GNU Privacy Guard”) [¹]:
sudo apt install pgpgpg
The pgpgpg program gives you a set of basic command line commands to create keys, encrypt and decrypt files. A tutorial can be found here [2].
A graphical user interface is the gpa (“GNU Privacy Assistant”) [3], which is explained nicely in this video tutorial [4, Linux@13m40s].
On Android the PGP app which I would recommend is OpenKeyChain [5].
Finally, to give you teaser, I have encrypted the following message using the password “pgptutorial” (which should normally be transferred through another channel) using the “symmetric” encryption method, which allows communicating with users who do not run PGP on their computer.
Message:
—–BEGIN PGP MESSAGE—–
jA0ECQMCAHHJx9uyL8b/0n0BvWnr5S7K/KHiLXZ+b9DGunY+hl/0aX015kT89I7j
Nu3ClmoTCo8hdpDFGpZnyc1qR6vRG32JZQzxegJVKFEV/F+oJwQsuVMCORJmgFow
AG/pbIM/8wxssPXdB0uKCQ4MZqMzuFPrC4xlW5A75CKVF8vhrVRBBYIrwE7eeg==
=4jNo
—–END PGP MESSAGE—–
My public key:
—–BEGIN PGP PUBLIC KEY BLOCK—–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=aHmK
—–END PGP PUBLIC KEY BLOCK—–
References:
- https://gnupg.org
- https://www.devdungeon.com/content/gpg-tutorial
- https://www.gnupg.org/related_software/gpa/
- https://www.youtube.com/watch?v=CEADq-B8KtI
- https://play.google.com/store/apps/details?id=org.sufficientlysecure.keychain&hl=en
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