If you send a normal email, you are sending a postcard. Anyone at the post office can read it. If you want to send a secret, you need a lockbox. But how do you lock the box if you can't physically give me the key?
PGP (Pretty Good Privacy) solves this by giving everyone TWO keys:
You don't need to do the math. Free software does it for you.
Windows: Download and install Gpg4win (Kleopatra).
Mac: Download and install GPG Suite.
Step 2: Forge Your KeysOpen the software (Kleopatra or GPG Keychain). Click "New Key Pair".
Enter your name and email. It will ask for a Passphrase. Make it a long sentence you won't forget. This passphrase protects your Private Key if someone steals your laptop. Click Generate.
Step 3: Get Your Padlock ReadyRight-click your newly created key in the list and select "Export". Ensure the box that says "Include Secret Key" is UNCHECKED. Save the file (it will end in .asc). This is your Public Key.
Now that you have your own keys, you need to lock a box with my padlock, and put your padlock inside the box so I can reply.
Download my Public Key here: Ozgur_Public_Key.asc
Open your PGP software and click "Import". Select the file you just downloaded. You now have my padlock.
Step 2: Write the MessageOpen a plain text editor (Notepad or TextEdit). Write your message. Important: Paste the text of your Public Key (the `.asc` file you made earlier) at the bottom of the message so I have it.
Step 3: Encrypt and SignHighlight all the text. Right-click and select "Encrypt" (or use the clipboard menu in Kleopatra).
A window will pop up asking who you are sending it to. Select Ozgur Susoy. Check the box that says "Sign" (this proves you wrote it) and select your own key.
Click Encrypt. Your text will turn into a giant block of random letters starting with -----BEGIN PGP MESSAGE-----.
Copy that giant block of random letters. Open your normal email (Gmail, etc.). Paste it into the body of the email. Send it to me.
If you did Phase 2 correctly, I now have your message and your Public Key. I will write a reply, lock it with your padlock, and email it back.
You will receive an email from me that looks like a block of random letters. Copy the entire block, including the -----BEGIN... and -----END... lines.
Right-click and select "Decrypt/Verify" (or use Kleopatra's clipboard tool).
Your software will ask for your Passphrase. Enter it.
The software will unlock the box, reveal my message, and tell you that the signature is valid. We now have a secure channel.