View Full Version : Sending/Receiving messages with Public Key Cryptography

ghetto alchemist
05-15-2015, 03:44 AM
Firstly, before you ever start sending/recieving encrypted messages, I ask that you would make a donation to Alchemy Forums, you´re about to use the site for something it was never intended for. Think how much it costs you to send a handwritten letter, think how much more it might cost to send a letter than nobody else can ever read except you. A professional service might charge you several dollars for each time you wish to send a secret message. Frankly it´s worth real money, alchemists from the old days couldnt have ever dreamed of this level of private correspondance. Pony up some money and pay for it. You can make an anonymous donation.....I did it by buying a pre-paid master card from the supermmarket (with cash), and used it to donate through the alchemy forums website hotlink. You will be asked for a pile of really personal information, but it doesnt need to be accurate. Paypal doesnt care, they just want their fee from the transaction, fill all the detail fields with fake information. It works, I´ve done it already. Dev got his money, even though it came from John Citizen on Anywhere Street, Anytown.

Ok so getting on with it....

How to create your own RSA Public key

What you need:

1 Linux installation CD to use as a boot disc....I recommend Ubuntu 10.04.4 LTS (Lucid Lynx)
(get it HERE: http://mirror.pnl.gov/releases/) because I´ve tested it and know that it works. But you should also be able to use other distros of linux as well.

1 blank USB stick to keep your encryption keys and messages on.

Get Started:
Pop your linux CD into your computer drive and boot into Linux from the CD. (You will need to set booting from CD in your bios) The linux CD will give you an option to boot from the CD or install linux, choose boot from CD.
Once you´re in Linux, pop your usb stick into the drive and find the path that leads to it, and write it down (you´ll need to know it later).
To do this, I double click the desktop icon for the usb drive and repeatedly click the up arrow, reading each directory that it jumps back from (reading the path in reverse). For my computer the path to the USB stick is

Open a terminal window.
Then enter this command: gpg --gen-key
select: (1) RSA and RSA
keysize: 2048 (or bigger)
expiry: 0 (never expire)
correct: y
Real Name: smithy (you use your own nic)
email address: (leave blank)[enter]
comment: (leave blank)[enter]
(O)kay/(Q)uit? : o
Enter passphrase: whatever_you_choose
Repeat passphrase: whatever_you_choose
generate random bytes: move mouse and type random stuff in your keyboard
(this last bit might take a while)

Once your encryption keys have been generated, you need to export them to your usb stick. Change ´smithy´ to your own nic, and ´USB/PATH´ to your own USB path.

Export your public key: gpg --export -a "smithy" > /USB/PATH/public.key

Export your private key: gpg --export-secret-key -a "smithy" > /USB/PATH/private.key

That´s it, you´re done, shutdown linux.
Boot into your normal OS, log into alchemy forums, copy the text from public.key into a message and post it up for everyone to have access to it.
By using your public key, anyone can send you encrypted messages.

Keep your private key for yourself only (you need it to read your own encrypted messages).


Instructions for sending me (or anyone else) an encrypted message:

save my public key to a file on your usb stick -> ghetto.key
(public keys available HERE (http://forum.alchemyforums.com/showthread.php?4406-Public-Keys-Here&p=38412#post38412))

save the message you want to send me to a file on usb stick -> message.txt

Boot into Linux with usb stick plugged in, and open a terminal window

import public key: gpg --import /USB/PATH/ghetto.key

encrypt: gpg -e -r "Ghetto Alchemist" /USB/PATH/message.txt
(creates file message.txt.pgp on USB stick)

convert to base64: base64 /USB/PATH/message.txt.pgp > /USB/PATH/message.txt.pgp.base64
(creates file message.txt.pgp.base64 on USB stick)

Shutdown linux, boot into your normal OS with USB stick still plugged in and log into alchemy forums.
Paste contents of message.txt.pgp.base64 into a message box and send it to me.


Instructions for reading an encrypted message sent to you by anyone else

In your normal OS save the encrypted message to USB stick, and give the file the name ¨decrypt.txt.pgp.base64¨

Shutdown your normal OS and boot into linux with USB stick inserted.
Open a terminal window...

Import your private key: gpg --allow-secret-key-import --import /USB/PATH/private.key

remove base64: base64 -d /USB/PATH/decrypt.txt.pgp.base64 > /USB/PATH/decrypt.txt.pgp

decrypt the mesage: gpg -d /USB/PATH/decrypt.txt.pgp > /USB/PATH/decrypt.txt

The message is in the file decrpt.txt, shutdown linux, boot back into your normal OS and read the message off your USB stick at your leisure.

ghetto alchemist
06-09-2015, 02:29 PM
Jeez, the thread with public keys hasn´t exactly been inundated with people´s encryption keys..which means:

1 Everyone is too poor to make a donation, therefore cant put their encyption keys up either
2 Nobody has anything sensitive enough to communicate to warrant using encryption for privacy
3 Everybody is running windows and not able to deal with ubuntu linux

In case of the last option, go to this link to get the same encryption/decrption software, but for windows: