Question

GnuPG --passphrase-fd option in BASH

Asked by: rblampain

Fedora C2.
I need to encrypt a file received by a CGI script and be able to decrypt it later. I need these processes automated.
I have made the following test script that I hoped would do both and can be split later:

#!/bin/bash
rm -f encrypted
cat phrase | gpg --batch --passphrase-fd 0 --output encrypted --encrypt unencrypted.txt
cat phrase | gpg --batch --passphrase-fd 0 --output decrypted --decrypt encrypted

"phrase" is a file containing a 32 bytes passphrase.

The encryption is working but the decryption is not, if I try to include -c or --symmetric in the first line then it doesn't work either.

gpg: encrypted with 1024-bit ELG-E key, ID 96C7D90C, created 2005-08-11
      "............................................................."
gpg: public key decryption failed: bad passphrase
gpg: decryption failed: secret key not available

Questions:
1)  can anyone correct the script? I have created a pair of asymmetric keys and it looks like the script is using it when I probably need it to use the symmetric key from the passphrase.
2) how can I suppress all comments? I thought --batch would do that.

Thank you for your help.

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2005-08-15 at 00:38:00ID21527030
Tags

gpg

,

passphrase

,

gnupg

,

key

Topic

Linux Network Security

Participating Experts
3
Points
500
Comments
18

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. bash };:
    I'm asking in this topic 'cause I think most bash experts can be found here;-) Here we go: can somebody please explain how the 2'nd and 3'rd : are interpreted by bash in following command. :() {;:};: I assume bash uses them as modifiers. NOTE, this command is dangero...
  2. encrypt and decrypt file using bash script
    hello.....can anybody teach me how to encrypt and decrypt file using bash script .....i really don't know how to do it...plz...
  3. bash variable encrypting
    How do I encrypt/decrypt a bash script variable? :S I have Linux SuSE 8.2. MMartha
  4. Problem with My Hello World BASH CGI
    Hi everyone, I'm playing around with Linux CGI using many languages. I got it to work with Perl, C, and C++. I now want it to work with BASH. I have a two files: cgi-bin/bash/index.bsh contains the following code: #!/bin/bash echo "Content-type: text/html";...
  5. CGI, Bash, Sudo, unix accounts, apache, form, vsf…
    Ok I need some help on this one. I have a bash script that runs every day that creates 10 randomly generated ftp accounts and emails the ftp links to a speific user. This user then distributes the FTP accounts to others. I would like to change this. I would like to allow user...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: veedarPosted on 2005-08-15 at 17:03:28ID: 14679080

Not sure where you went wrong but here's what worked for me.
Create a key first with...

gpg --gen-key

...I used the example from the docs to create a key and assign a passphrase like this
USER-ID: "Heinrich Heine (Der Dichter) <heinrichh@duesseldorf.de>"

I then used it successfully with the -r option like so...
cat phrase | gpg --batch --passphrase-fd 0 --output encrypted --encrypt -r heinrichh@duesseldorf.de  unencrypted.txt

cat phrase | gpg --batch --passphrase-fd 0 --output decrypted --decrypt -r heinrichh@duesseldorf.de encrypted



 

by: rblampainPosted on 2005-08-15 at 20:27:32ID: 14679980

Thanks veedar. I'll start from scratch and see what happens.

 

by: rblampainPosted on 2005-08-15 at 21:08:20ID: 14680139

I deleted the keys, generated a new pair and tried it as you suggested but the result is exactly the same, encrypting works but decrypting does not.

 

by: veedarPosted on 2005-08-16 at 05:39:11ID: 14681947

Do you have the latest version of gpg installed?

What do you get when you run...

gpg --list-secret-keys

gpg --list-keys

 

by: rblampainPosted on 2005-08-16 at 06:29:46ID: 14682362

I have deleted the keys because the asymmetric encryption didn't work, but the commands you mentioned showed the keys before I deleted them. I have kernel 2.6.12.3 and I think I have a recent version of GPG.
It looks like because I want to be able to encrypt and decrypt, the symmetric encryption is a lot easier to use, the asymmetric encryption may require the use of some tricks (pretending to send and receive the encrypted file or something).
I just found the commands below work (no keys at all exist) and I think I'll leave it at that.  
Thank you very much for your persistence.

gpg  --symmetric --batch --passphrase-fd 0 <pass --output encrypted encrypt
gpg  --batch --passphrase-fd 0 <pass -d --output decrypted encrypted

"pass" is the file containing the passphrase
encrypt is the file to encrypt
encrypted is the output file of the encryption command
decrypted is the output file of the decrypting command

Hope this helps somebody.

 

by: mbarbosPosted on 2005-08-16 at 06:40:40ID: 14682441

Can you please try:

echo passphrase | gpg ....

and also to add a return at the end of the phrase file and try again ?

 

by: rblampainPosted on 2005-08-16 at 07:20:55ID: 14682871

To mbarbos: I just tried your suggestion and the result is exactly the same. Whether there is a return or not at the end of the passphrase file makes no difference. I tried a few combinations.

 

by: mbarbosPosted on 2005-08-16 at 07:27:07ID: 14682929

Hmm, I tried with gpg 1.2.6 and 1.4.2 and you initial commands work without any problems (ok, I need and -r since the username and the name on the keys are different). Maybe you should try another gnupg package.

 

by: rblampainPosted on 2005-08-16 at 20:21:17ID: 14688791

I just checked, the version og gpg on my machine is 1.2.4. I'll upgrade and give it another try just out of curiosity.

 

by: rblampainPosted on 2005-08-17 at 00:28:19ID: 14689511

I installed gpg 1.4.2,  and generated the keys, here is the result:

gpg: key 79E7ACD4 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:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
pub   1024D/79E7ACD4 2005-08-17
      Key fingerprint = 9E1A EF32 CE60 47AC 282D  4560 1704 4D36 79E7 ACD4
uid                  myname (mycomment) <myname@myisp.com>
sub   2048g/62C0E506 2005-08-17

The result is different when using the commands in the initial post above.
I get the following message after commenting out the decryption line.

 myname@myisp.com: skipped: public key not found
gpg: unencrypted.txt: encryption failed: public key not found
The passphrase entered when generating the keys is the same than the one contained in the file "phrase".

 

by: mbarbosPosted on 2005-08-17 at 01:38:21ID: 14689757

Running it from the console gives me a different result:

cat phrase | gpg --batch --passphrase-fd 0 --output encrypted --encrypt -r myname minicom.log

cat phrase | gpg --batch --passphrase-fd 0 --output decrypted --decrypt encrypted
gpg: encrypted with 2048-bit ELG-E key, ID 1B5DF7E9, created 2005-08-17
      "myname (mycomment) <myname@myisp.com>"

Did you try running the commands from the console instead of a script ? There are environment differences between a script and the command line.

 

by: rblampainPosted on 2005-08-17 at 05:39:22ID: 14690886

I ran the commands as a script because the process need to be automated.

 

by: mbarbosPosted on 2005-08-17 at 05:45:56ID: 14690936

Can you check them also as command line ?
If they work than all we have to do is to supply the scripts the missing data. Actually I suspect it's a env variable missing and gpg doesn't find its key

 

by: rblampainPosted on 2005-08-17 at 06:29:14ID: 14691208

Running it at the command line gives the same result although a bit shorter: ".. key not found".

 

by: mbarbosPosted on 2005-08-17 at 06:36:22ID: 14691278

Funny..

Can you try
gpg --list-keys
gpg --list-public-keys
gpg --list-secret-keys

 

by: rblampainPosted on 2005-08-17 at 08:36:26ID: 14692519

This shows nothing, it looks like the --gen-key I did after installing the new version of gpg didn't work. I generated the keys again and now everything works, command line and script.

I feel guilty of having allocated the points a little prematurely.

 

by: mbarbosPosted on 2005-08-17 at 08:39:30ID: 14692557

No big deal

Glad I could be of some help :-)

 

by: natmaPosted on 2005-10-18 at 12:46:45ID: 15110796

more efficiently:
recreate a key pair (--gen-key) then crypt w your public key, using
'gpg -q -e -r YourKeyID FileName'

this way you won't have to let any password on the machine running the script.  keep a copy of your secret key file (probably ~/.gnupg/secring.gpg) in a multiple VERY safe places away from the machine (think flood and fire) and DO NOT forget your passphrase to it

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...