Wilders Security Forums How to decrypt PGP files ?
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#1
November 23rd, 2010, 04:11 AM
 AvinashR Very Frequent Poster Join Date: Dec 2009 Location: New Delhi Metallo β-Lactamase 1 Posts: 2,060
How to decrypt PGP files ?

Hi Guys,

I am having a problem with PGP files. I am unable to find out how to decrypt PGP encrypted files? I need to decrypt some of the PGP files. I do have the public of the owner who encrypted these files, but the guy is from China and i am unable to understand his terrible English.

So it would be great if somebody tell me "How to decrypt PGP encrypted files?" and also do let me know which software i can use and how can i create my own PGP Key?

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#2
November 23rd, 2010, 04:39 AM
 raspb3rry Infrequent Poster Join Date: Jun 2010 Posts: 37
Re: How to decrypt PGP files ?

You could try using the GUI-tool called The GNU Privacy Assistant.
It is a frontend for the gpg-program, which is 100% compitable with OpenPGP.
It seems to be the easiest way to encrypt/decrypt files, without using the commandline.
#3
November 23rd, 2010, 05:12 AM
 AvinashR Very Frequent Poster Join Date: Dec 2009 Location: New Delhi Metallo β-Lactamase 1 Posts: 2,060
Re: How to decrypt PGP files ?

Quote:
 Originally Posted by raspb3rry You could try using the GUI-tool called The GNU Privacy Assistant. It is a frontend for the gpg-program, which is 100% compitable with OpenPGP. It seems to be the easiest way to encrypt/decrypt files, without using the commandline.

Thanks for the software. But please let me know how to decrypt the PGP file? Should i use my own PGP key or the owner's public PGP key? Secondly i am not aware "How to create my own PGP key.."

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#4
November 23rd, 2010, 05:53 AM
 raspb3rry Infrequent Poster Join Date: Jun 2010 Posts: 37
Re: How to decrypt PGP files ?

Do you have a PGP key?
Otherwise I'm quite sure that you can make one in the program I linked to.

When encrypting files with PGP/GPG you would normally use the public key of reciever, which in this case is you. The public key allows everyone to encrypt files, that only you and your secret key can decrypt.

However, PGP/GPG does also support symmetrical encryption, in which case you should be able to decrypt the file this way:
1) Press WIN+R
2) Type "cmd" and press enter.
3) Make sure that you have gpg installed.
4) Type gpg --decrypt-files C:\path\to\encrypted\file
5) Type in the password that the sender used to encrypt the file.
6) The file should be decrypted now.

Encrypted PGP-files usually have the extensions *.pgp, *.gpg or *.asc.

Please note that you would need to know the password/-phrase that the sender have used to encrypt the file.
#5
November 23rd, 2010, 06:01 AM
 AvinashR Very Frequent Poster Join Date: Dec 2009 Location: New Delhi Metallo β-Lactamase 1 Posts: 2,060
Re: How to decrypt PGP files ?

Thanks bro.

I have the password/-phrase that sender/owner used to encrypt the file. I will try to decrypt with your steps. If i won't succeed i will ask you furthermore.
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#6
November 23rd, 2010, 06:56 AM
 raspb3rry Infrequent Poster Join Date: Jun 2010 Posts: 37
Re: How to decrypt PGP files ?

It seems like there's an easier way:

In step 4, it should be possible to just write:
Code:
gpg C:/path/to/encrypted/file

I'm running Linux, so please excuse me. This should work in Windows too.
#7
November 23rd, 2010, 10:12 AM
 AvinashR Very Frequent Poster Join Date: Dec 2009 Location: New Delhi Metallo β-Lactamase 1 Posts: 2,060
Re: How to decrypt PGP files ?

Unable to perform this.. How can i install the software? There is no option in it to install
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#8
November 23rd, 2010, 10:50 AM
 tobacco Frequent Poster Join Date: Nov 2005 Location: British Columbia Posts: 1,462
Re: How to decrypt PGP files ?

Quote:
 Originally Posted by AvinashR Unable to perform this.. How can i install the software? There is no option in it to install

Look through the secure email threads available in this section. You can use a simple program like "InstantCrypt" and have it create a public/private key for you. Send your public key to your contact and ask him/her to resend the email encrypted with your public key which IC will decrypt for you.
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#9
November 23rd, 2010, 10:56 AM
 raspb3rry Infrequent Poster Join Date: Jun 2010 Posts: 37
Re: How to decrypt PGP files ?

When you've installed that, you should be able to follow my steps in the previous posts.

Last edited by Cudni : November 23rd, 2010 at 01:14 PM. Reason: disabled .exe link
#10
November 24th, 2010, 05:17 AM
 Warlockz Frequent Poster Join Date: Oct 2008 Posts: 642
Re: How to decrypt PGP files ?

Try gpg4usb

Quote:
 Originally Posted by gpg4usb.cpunk.de gpg4usb is a very easy to use and small portable editor to encrypt and decrypt any text-message or -file you want.
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Last edited by Warlockz : November 24th, 2010 at 05:52 AM.
#11
November 24th, 2010, 07:25 AM
 AvinashR Very Frequent Poster Join Date: Dec 2009 Location: New Delhi Metallo β-Lactamase 1 Posts: 2,060
Re: How to decrypt PGP files ?

Done everything.. Installed GPG4WIN and tried to decrypt it, but all in vain. I have owners public key but i am not sure how if i am doing the right thing or not. I have already import his key and make it "Ultimate Trusted" and use it again to decrypt the file.

Lemme tell you that the file is about 863 MB and every time i am trying to decrypt it, it shows verification failed.
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#12
November 24th, 2010, 01:54 PM
 raspb3rry Infrequent Poster Join Date: Jun 2010 Posts: 37
Re: How to decrypt PGP files ?

Have you and your chinese friend compared the md5-hashes of the encrypted file? Some data could have been lost during the transfer, resulting in corrupt data...
#13
November 25th, 2010, 07:56 AM
 AvinashR Very Frequent Poster Join Date: Dec 2009 Location: New Delhi Metallo β-Lactamase 1 Posts: 2,060
Re: How to decrypt PGP files ?

Quote:
 Originally Posted by raspb3rry Have you and your chinese friend compared the md5-hashes of the encrypted file? Some data could have been lost during the transfer, resulting in corrupt data...

Yeah i am also looking that thing too. Lemme get back to you guys after confirming this ...
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#14
November 26th, 2010, 06:06 AM
 GlobalForce Regular Poster Join Date: Jun 2004 Location: Garden State, USA Posts: 3,581
Re: How to decrypt PGP files ?

Keep in mind Avinash - "Send your public key to your contact and ask him/her to resend the email encrypted with your public key."
#15
December 9th, 2010, 07:38 PM
 chronomatic Very Frequent Poster Join Date: Apr 2009 Posts: 1,342
Re: How to decrypt PGP files ?

Quote:
 Originally Posted by AvinashR Done everything.. Installed GPG4WIN and tried to decrypt it, but all in vain. I have owners public key but i am not sure how if i am doing the right thing or not. I have already import his key and make it "Ultimate Trusted" and use it again to decrypt the file. Lemme tell you that the file is about 863 MB and every time i am trying to decrypt it, it shows verification failed.

You cannot decrypt the file with his public key. It doesn't work that way.

First of all, as was stated above, it depends on how the guy encrypted the file. Did he use the symmetric or asymmetric method? If he used YOUR public key to encrypt the file (which is usually how it's done), then all you need is your private key. If he just encrypted it symetrically (with a passphrase), you need the passphrase.