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What
is PGP?
Pretty Good™
Privacy (PGP), from Phil's Pretty Good Software, is a high
security cryptographic software application for MSDOS,
Unix, VAX/VMS, and other computers. PGP allows
people to exchange files or messages with privacy,
authentication, and convenience. Privacy means that
only those intended to receive a message can read it.
Authentication means that messages that appear to be from
a particular person can only have originated from that
person. Convenience means that privacy and
authentication are provided without the hassles of
managing keys associated with conventional cryptographic
software. No secure channels are needed to exchange
keys between users, which makes PGP much easier to use.
This is because PGP is based on a powerful new technology
called
public key cryptography.
Using PGP
In order to
use PGP, you will first need to create a key set.
1.
SSH into your account.
2.
Run the
command "pgpk -g". This will prompt you for the
following information:
*Choose
the type of your public key.
1.
DSS/Diffie-Hellman - New algorithm for 5.0 (default)
2. RSA
Choose 1 or 2: -"Select RSA"-
*Pick
your public/private keypair key size.
1.
768 bits- Commercial grade, probably not currently
breakable
2. 1024 bits- High commercial grade, secure
for many years
3. 2048 bits- "Military" grade,
secure for the foreseeable future
Choose 1, 2 or 3, or enter desired number of bits
(768 - 2048): -"A key of 1024 bits is
more than enough, select that".
*Enter
a user ID for your public key.
The
desired form for this user ID is your FULL name,
followed by your
E-mail address enclosed in <angle
brackets>, if you have an E-mail address.
For example:
Joe Smith <user@domain.com>
If you violate this standard, you will lose much
of the benefits of
PGP 5.0's keyserver and email integration.
Enter a user ID for your public key:
-"Fill in the appropriate info"-
*Enter
the validity period of your key in days from 0 - 999.
0
is forever (and the default): -"Enter 0 if
you want this key to last forever"-
*Choose
a pass phrase to protect your private key(s).
Your
pass phrase can be any sentence or phrase and may have
many
words, spaces, punctuation, or any other
printable characters.
Enter pass phrase: -"Fill in a good
passphrase that you are sure to remember"-
3.
Run the
command "pgpk -xa userid -o public.key" (userid
refers to the user ID on step 2) This will produce a file
called "public.key".
*You can
also download pgp from
http://www.pgp.com/ and
create a keyset on your home computer.
Once
this key set is created, you can start encrypting files on
from SSH.
1.
SSH into your account.
2. Run
the command "pgp -r userid file -o file.pgp"
("file" refers to the file you wish to encrypt).
This will produce an file"file.pgp" with the
encrypted content of "file".
PGPMail
From your
Control Panel (http://www.yourdomain.com/menu) select
PGP.
1.
Copy
the contents of the file "public.key" created in
step 3 of the previous section. If you created the key
with PGP on your home computer copy the contents to the
appropriate section.
2. Click
on "Add". (You may not need to run this step if
you created the key from SSH.
3. Click
on "To test sending a PGPMail".
You need to
set up your form to use the
'pgpmail.pl'
The form
action line should be
<FORM ACTION = "/cgi-sys/pgpmail.pl"
METHOD = "POST">
The
'pgpmail.pl' will
do all the programming work for you. You alter the
behavior of
'pgpmail.pl' by
using hidden fields in your form.
There are
three form fields that you must have in your form for
PGPMail to work correctly, recipient, username, and
keyname.
Field:
recipient
Description:
This form field allows you to specify to whom you wish
for your
form results to be mailed. Most likely you will want to
configure this option
as a hidden form field with a value equal to that of
your e-mail address.
Syntax:
<input type=hidden name="recipient"
value="your_username@localnet.com">
Field:
username
Description:
This form field allows you to specify your username in
the system. This allows PGPMail to look for the
configuration files to encrypt the mail to be sent to
you.
Syntax:
<input type=hidden name="username"
value="your_username">
Field:
keyname
Description:
This form field allows you to specify the name of your
public key.
This will be the public key that PGPMail uses to encrypt
your mail. You must
possess the private key in order to decrypt the email
that is sent.
Syntax:
<input type=hidden name="keyname"
value="public_keyname">
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