File encription by GPG and OpenSSL

Posted on Sat 14 February 2009

Without public key

GPG

# encrypt
gpg -c khmel.tar.gz
# decrypt
gpg khmel.tar.gz.gpg

OpenSSL

# encrypt
openssl des3 -salt -in khmel.tar.gz -out encryptedfile.txt
# decrypt
openssl des3 -d -salt -in encryptedfile.txt -out khmel.tar.gz

With public key

$ gpg --gen-key

Please select what kind of key you want:
 (1) DSA and Elgamal (default)
 (2) DSA (sign only)
 (5) RSA (sign only)
Your selection? 1

DSA keypair will have 1024 bits.
ELG-E keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048)
Requested keysize is 2048 bits
Please specify how long the key should be valid.
 0 = key does not expire
 <n> = key expires in n days
 <n>w = key expires in n weeks
 <n>m = key expires in n months
 <n>y = key expires in n years
Key is valid for? (0) 2

Key expires at Mon 16 Feb 2009 04:13:08 PM EET
Is this correct? (y/N) y

You need a user ID to identify your key; the software constructs the user ID
from the Real Name, Comment and Email Address in this form:
   "Heinrich Heine (Der Dichter) <heinrichh@duesseldorf.de>"

Real name: khmel.org

Email address: test@khmel.org
Comment: test
You selected this USER-ID:
 "khmel.org (test) <test@khmel.org>"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O

You need a Passphrase to protect your secret key.

<moving mouse, press different key on keyboard>

gpg: key EA1D37CB marked as ultimately trusted
public and secret key created and signed.

gpg: checking the trustdb
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0  valid:   2  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 2u
gpg: next trustdb check due at 2009-02-16
pub  1024D/EA1D37CB 2009-02-14 [expires: 2009-02-16]
      Key fingerprint = FAD0 8249 4BAF B464 3121  D058 71D0 3EAA EA1D 37CB
uid                 khmel.org (test) <phn@khmel.org>
sub   2048g/DB5F05BA 2009-02-14 [expires: 2009-02-16]

Prepare public key

gpg --export --armor > alpha-public-key.asc

Using public key

Import

gpg --import /home/alpha/Desktop/beta-public-key.asc

List keys

$ gpg --list-key
/home/alpha/.gnupg/pubring.gpg
---------------------------------- pub  1024D/EA1D37CB 2009-02-14 [expires: 2009-02-16]
uid                 khmel.org (test) <test@khmel.org>
sub  2048g/DB5F05BA 2009-02-14 [expires: 2009-02-16]
pub  1024D/4B9A45AF 2009-02-14 [expires: 2009-02-17]
uid                 beta (test) <beta@khmel.org>
sub  2048g/1C413E51 2009-02-14 [expires: 2009-02-17]

Encrypt file

gpg -e -r 'beta' /home/alpha/Desktop/secret.txt
[/bahs]

Decrypt file

gpg -d /home/beta/Desktop/secret.txt.gpg
```