How to use pgp

nigelc · 08-20-2012, 03:12 AM

Hello,
Is there a step by step guide how to use pgp? /seahorse?

The manpage has lots of stuff on it, but not sure what to look for.

cheers nigel

acid_kewpie · 08-20-2012, 03:21 AM

well it depends what you want to do, doesn't it? That's *EXACTLY* why there's lots in the man page. if it was just a few steps to cover the one thing it did, that's all the man page would list. That said, there certanly are many thousands of blog entries and other docs out there where someone has written down how to do the specific thing *they* wanted, but if that's not the same as what you want, it's not going to help much is it?

nigelc · 08-20-2012, 06:51 AM

encrypt and decrypt some files.
I have some old files that I cannot un-encrypt .
It is difficult to use.
I can click on old pgp file, but cannot see anything.

Mr. Alex · 08-20-2012, 08:35 AM

To use symmetric algorythm for encrypting files you do

Code:

gpg -c file

It will use CAST5 by default which is very strong.
If you want to use other algorythm

Code:

gpg -c --cipher-algo ... file

Available algorythms:

Code:

3DES         AES          AES192       AES256       BLOWFISH     CAMELLIA128  CAST5        TWOFISH

Use one of them instead of "...".

To decrypt:

Code:

gpg file.gpg

You will have to enter a passphrase and if you forget it - file's gone. Unless it was dictionary passphrase and you can bruteforce it, there's nothing you can do to restore passphrase. GnuPG is not a toy.

You can also use asymmetric algorythms to encrypt files and e-mails but that is a bit more complicated. Let me know if you need a HOWTO.

chrism01 · 08-20-2012, 10:02 PM

Try this http://www.gnupg.org/gph/en/manual.html
Has examples as well as background explanations.

nigelc · 08-21-2012, 12:28 AM

Thanks for the help.
I can encrpyt a file, but I cannot get to this old one.
I don't know which version of gpg it comes from. The data is not all that important. I saved a copy in plain text in case this might happen.

Code:

[ewok@endor Desktop]$ gpg Bank_xfer1.doc.pgp 
gpg: encrypted with ELG-E key, ID E5E1AC81
gpg: decryption failed: secret key not available

John VV · 08-21-2012, 12:39 AM

this might be a "problem"

Quote:

I have some old files that I cannot un-encrypt .
...............
I can encrpyt a file, but I cannot get to this old one.

do you have the OLD hash for them? or the old "key"?
if not this might be a unsolvable problem

HOW were they encrypted ? and using WHAT program ?

some older encryption programs DO have some known "bugs" that might make it possible to CRACK them ?????? or not .

there are some "cracking" tools to break encryption using the GPU and CUDA but...................

nigelc · 08-21-2012, 12:53 AM

They were encrypted with gpg /Fedora 5.

Does the data exprire after time?

John VV · 08-21-2012, 01:13 AM

the engine used in the antique fedora5 is vastly different than the one used in fedora 17

and a few known holes have been fixed and a new algorithm is used ( i think)
BUT unless you ARE a EXPERT in "cracking" encrypted files there is no easy way to unencrypt the files WITHOUT the original fedora key FROM the old fedora 5 install
even then was it gnomes key ring ? or KDE3's key ring ?
or
a public / private pair with the public half posted to a public server
and the private on the fedora key-ring ( or 3.5 floppy)

Quote:

Does the data exprire after time?

no, unless YOU set it to
but after time the old keys get lost

And on fedora with a NEW install EVERY 6 months
not only is it likely but almost a 100% certain fact that they WILL get lost