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“UbuntuHelp:GnuPrivacyGuardHowto”的版本间的差异

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=== Validation on Launchpad ===
 
=== Validation on Launchpad ===
  
You need to enter the GPG fingerprint at [[UbuntuHelp:https://launchpad.net/~<username>/+editpgpkeys]].  To obtain it, type:
+
You need to enter the GPG fingerprint at [[https://launchpad.net/~<username>/+editpgpkeys]].  To obtain it, type:
  
 
<pre><nowiki>
 
<pre><nowiki>
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* During this meeting you hand each other your OpenPGP key fingerprint and at least one government issued ID '''with a photograph'''. These key fingerprints are usually distributed as key fingerprint slips, created by a script such as gpg-key2ps (package: signing-party)
 
* During this meeting you hand each other your OpenPGP key fingerprint and at least one government issued ID '''with a photograph'''. These key fingerprints are usually distributed as key fingerprint slips, created by a script such as gpg-key2ps (package: signing-party)
 
* You check whether the name on the key corresponds with the name on the ID and whether the person in front of you is indeed who he says he is.
 
* You check whether the name on the key corresponds with the name on the ID and whether the person in front of you is indeed who he says he is.
* Having done these two checks, you only need to check whether this person is in control of the private key. You do this by sending him/her back his/her signed public key, encrypted with his public key. The caff program makes this part very easy. You need to create a file named <code><nowiki>.caffrc</nowiki></code> in your homedir (only once) with the following content:<pre><nowiki>
+
* Having done these two checks, you only need to check whether this person is in control of the private key. You do this by sending him/her back his/her signed public key, encrypted with his public key. The caff program makes this part very easy. You need to create a file named <code><nowiki>.caffrc</nowiki></code> in your homedir (only once) with the following content:  
 +
<pre><nowiki>
 
$CONFIG{owner} = q{Your full name here};
 
$CONFIG{owner} = q{Your full name here};
 
$CONFIG{email} = q{The emailaddress used in your key here};
 
$CONFIG{email} = q{The emailaddress used in your key here};
$CONFIG{keyid} = [ qw{last 16 characters of your key fingerprint here} ];</nowiki></pre> Now you can simply run the following command:<pre><nowiki>
+
$CONFIG{keyid} = [ qw{last 16 characters of your key fingerprint here} ];</nowiki></pre> Now you can simply run the following command:  
 +
<pre><nowiki>
 
caff key_id_of_other_persons_key</nowiki></pre>
 
caff key_id_of_other_persons_key</nowiki></pre>
* When you receive signed keys from others, you get them as attachment, save these attachments and import them with gpg. You can then send this signature to the keyservers so other people can know about it<pre><nowiki>
+
* When you receive signed keys from others, you get them as attachment, save these attachments and import them with gpg. You can then send this signature to the keyservers so other people can know about it.
 +
<pre><nowiki>
 
gpg --import filename_of_saved_signature
 
gpg --import filename_of_saved_signature
 
gpg --send-keys $GPGKEY</nowiki></pre>
 
gpg --send-keys $GPGKEY</nowiki></pre>
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When you've set up GnuPG and have a key in the strong set, it is time to sign the Ubuntu Code Of Conduct if you want to become an Ubuntu member or Ubuntero. Signing is done in 3 easy steps:
 
When you've set up GnuPG and have a key in the strong set, it is time to sign the Ubuntu Code Of Conduct if you want to become an Ubuntu member or Ubuntero. Signing is done in 3 easy steps:
 
* Download the code of conduct from https://launchpad.net/codeofconduct/1.0.1.
 
* Download the code of conduct from https://launchpad.net/codeofconduct/1.0.1.
* Run the command<pre><nowiki>
+
* Run the command  
 +
<pre><nowiki>
 
gpg --clearsign UbuntuCodeofConduct-1.0.1.txt</nowiki></pre>
 
gpg --clearsign UbuntuCodeofConduct-1.0.1.txt</nowiki></pre>
 
* Upload the contents of Ubuntu``Codeof``Conduct-1.0.txt.asc on https://launchpad.net/codeofconduct/1.0.1/+sign
 
* Upload the contents of Ubuntu``Codeof``Conduct-1.0.txt.asc on https://launchpad.net/codeofconduct/1.0.1/+sign

2007年5月24日 (四) 11:52的版本


"GnuPG uses public-key cryptography so that users may communicate securely. In a public-key system, each user has a pair of keys consisting of a private key and a public key. A user's private key is kept secret; it need never be revealed. The public key may be given to anyone with whom the user wants to communicate." -GnuPG Manual

Topics Covered

The following topics will be covered by this article.

  • GnuPG, gpg,gpg2, PGP and OpenPGP
  • Generating an OpenPGP key
  • Uploading key to keyserver
  • Keysigning
  • Signing Data
  • Configuring your mail clients to use GPG

GnuPG, GPG, PGP and OpenPGP

OpenPGP, PGP and GnuPG / GPG are often used interchangeably - a common mistake.

  • OpenPGP is technically a proposed standard although it is widely used.
  • PGP is an acronym for Pretty Good Privacy, a computer program which provides cryptographic privacy and authentication.
  • GnuPG is an abreviation for Gnu Privacy Guard, another computer program which provides cryptographic privacy and authentication.

PGP and GnuPG are computer programs that implement the OpenPGP standard. To find out more about those see http://en.wikipedia.org/wiki/Pretty_Good_Privacy

Generating an OpenPGP Key

The core package required to start using OpenPGP, gnupg, is installed by default on Ubuntu systems. While the default package gnupg is installed (version 1.4.6) The difference between the two is while 1.4.7 is the well known and portable standalone version.


There are several programs which provide a graphical interface to the GnuPG system.

  • Enigmail, an OpenPGP plugin including key management for Mozilla Thunderbird. sudo apt-get install mozilla-thunderbird-enigmail
  • GNU Privacy Assistant (gpa) sudo apt-get install gpa
  • Seahorse sudo apt-get install seahorse
  • KGPG, for a KDE interface. sudo apt-get install kgpg

You can also generate keys using these programs and use the section below for recommendations.

Using GnuPG

 
gpg --gen-key

This will lead to a selection screen with the following options

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

The default choice (1) is preferred, since the others cannot be used for encryption.

What keysize do you want? (2048)

A keysize of 2048 (which is the default) is also a good choice.

Key is valid for? (0)

Most people make their keys valid until infinity, which is the default option. If you do this don't forget to revoke the key when you no longer use it (see later). Hit Y and proceed.

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) <[email protected]>"

Real name: Dennis Kaarsemaker
Email address: [email protected]
Comment: Tutorial key
You selected this USER-ID:
"Dennis Kaarsemaker (Tutorial key) <[email protected]>"

Make sure that the name on the key matches the name in your passport, or other government issued photo-identification! You can add extra e-mail addresses to the key later.

Type O to create your key.

You need a Passphrase to protect your secret key.

You will be asked for your passphrase twice. Usually, a short sentence or phrase that isn't easy to guess can be used. You would be asked to tap on the keyboard or do any of the things you normally do in order for randomization to take place. Do not know the reasons behind this but guess it makes things slightly more secure?

IMPORTANT - Forgetting your passphrase will result in your key being useless. Remember this passphrase carefully, there is no way to recover it when it's lost. After you type your passphrase twice, the key will be generated. Please follow the instructions on the screen till you reach a screen similiar to the one below.

gpg: key D8FC66D2 marked as ultimately trusted
public and secret key created and signed.

pub   1024D/D8FC66D2 2005-09-08
Key fingerprint = 95BD 8377 2644 DD4F 28B5  2C37 0F6E 4CA6 D8FC 66D2
uid                  Dennis Kaarsemaker (Tutorial key) <[email protected]>
sub   2048g/389AA63E 2005-09-08

The key-id is D8FC66D2 (yours will be different).

Tip: It's probably a good idea to set this key as default in your .bashrc, so that applications using GPG can automatically use your key. Do this by entering the line below in your ~/.bashrc. Please note that will be sourced only during your next session, unless you source it manually.

export GPGKEY=D8FC66D2

Now restart the gpg-agent and source your .bashrc again:

killall -q gpg-agent
eval $(gpg-agent --daemon)
source ~/.bashrc

Revocation Certificate

A revocation certificate must be generated to revoke your public key if your private key has been compromised in any way. You can create a revocation certificate by doing

gpg --output revoke.asc --gen-revoke <KEY-ID>

The key may be printed and stored carefully preventing access to it. Anybody having access to your revocation certificate can render the public key useless.

Uploading the Key to Ubuntu keyserver

This section explains how to upload your key to a keyserver so that anyone can download it. When you have uploaded it to one keyserver, after a short time, all the keyservers will have it. You can help this process along by sending your key to several keyservers.

Using GnuPG:

gpg --send-keys --keyserver keyserver.ubuntu.com <KEY-ID>

using the above example it would be

gpg --send-keys --keyserver keyserver.ubuntu.com D8FC66D2

Using a webbrowser:

  • Export your key by doing gpg --export -a "Key-ID" > public.key
  • Copy the content of public.key:
  • Open http://pgp.mit.edu in a browser window.
  • Paste the copied content in the box under the label, Submit a key
  • Click on Submit this key to the keyserver!

Reading OpenPGP E-mail

OpenPGP implementations can be used to digitally sign, encrypt, and decrypt email messages for heightened security. You can register your own personal OpenPGP keys with Launchpad, and under some situations, Launchpad will send you signed or encrypted email. You would then use OpenPGP support in your mail reader to decrypt these messages or verify a message's digital signature. Of course, you can also use the OpenPGP support in your mail reader to trade encrypted messages with your colleagues, or sign your own messages so that others can have better assurances that the email that appears to come from you actually does comes from you.

The instructions below are not intended to provide you with detailed information on OpenPGP, its various implementations, or its use. These instructions simply provide links that can help you set up your mail reader to be compatible with OpenPGP signed and/or encrypted email.

We need your help to flesh out these instructions! Linux mail readers Thunderbird

You probably want [WWW] Enigmail, a Thunderbird add-on. On Ubuntu systems, you should just install the mozilla-thunderbird-enigmail package; I think this will install everything you need to get started with reading GPG signed and/or encrypted email. [BarryWarsaw 2007-04-04]. Evolution

Evolution has built-in support for OpenPGP. Look under the Security tab when you edit accounts. Claws Mac OS X mail readers Mail.app

[WWW] GPGMail from Sen:te is an excellent plugin for Apple's Mail.app mail reader. It has great support for reading GPG signed and/or encrypted email, assuming you already have GnuPG installed on your Mac (if not, the Sen:te pages can help you with that). The plugin is easy to install, easy to use, and seems very stable. I have only tried it with Mail.app on Mac OS X 10.4. [BarryWarsaw 2007-04-04] Thunderbird

You probably want [WWW] Enigmail, a Thunderbird add-on. Although I have not tried it, you should just be able to install this plugin into your Thunderbird and be good to go. [BarryWarsaw 2007-04-04]. Entourage Windows mail readers Outlook Outlook Express Thunderbird

You probably want [WWW] Enigmail, a Thunderbird add-on. Although I have not tried it, you should just be able to install this plugin into your Thunderbird and be good to go. [BarryWarsaw 2007-04-04]. Miscellaneous Google mail (Gmail)

Something like the [WWW] FireGPG Firefox plugin might do the trick.

(add yours here)


Making an ASCII armored version of Public Key

There are several sites out there that also allow you to paste an ASCII armored version your public key to import it. This is the preferred method, because the key comes directly from the user - as opposed to fetching from a keyserver, where the key may be corrupted, or the keyserver unavailable. To create an ASCII armored version of your public key using GnuPG, use the following command:

gpg --export -a <Key-ID> > mykey.asc

or, using the above example

gpg --export -a D8FC66D2 > mykey.asc


Validation on Launchpad

You need to enter the GPG fingerprint at [<username>/+editpgpkeys ]. To obtain it, type:

gpg --fingerprint <key-id> 

or, using the above example:

gpg --fingerprint D8FC66D2

which should output the

public key/date of creation
key fingerprint = 10 blocks of 4 alphanumeric words
uid  comment with email addresss
sub private key/date of creation

Example from above

pub   1024D/D8FC66D2 2005-09-08
Key fingerprint = 95BD 8377 2644 DD4F 28B5  2C37 0F6E 4CA6 D8FC 66D2
uid                  Dennis Kaarsemaker (Tutorial key) <[email protected]>
sub   2048g/389AA63E 2005-09-08

Now copy this fingerprint (yours will be different) to the fingerprint field on launchpad.

Now click on the "Import" button.

This will generate an encrypted email from "Launchpad OpenPGP Key Confirmation <[email protected]>"

If you are on gmail, using the FireGPG addon, simply scroll down and click "decrypt this mail". You will now see the decrypted message with a link and a token. Copy that URL:

https://beta.launchpad.net/token/somealphanumerictoken

Click on "Confirm". Please note that validation does take some time. If you run into an internal 500 server, simply try again with the same token.

A confirming page should appear once the validation is successfully completed.


Getting your key signed

The whole point of all this is to create a web of trust. By signing someone's public key, you state that you have checked that the person that uses a certain keypair, is who he says he is and really is in control of the private key. This way a complete network of people who trust each other can be created. This network is called the Strongly connected set. Information about it can be found at http://pgp.cs.uu.nl/

In summary,

  • Locate someone that lives near you and can meet with you to verify your ID. Sites like http://www.biglumber.com/ are useful for this purpose
  • Arrange for a meeting. Bring at least one ID with photo and printed fingerprint of your OpenPGP key, ask the same from the person you will be meeting with.
  • Meet, verify your IDs and exchange OpenPGP key fingerprints
  • Sign the key of the person you've just met. Send him/her the key you've just signed.
  • Update your keys on the keyserver, the signature you've just created will be uploaded.

Keysigning Guidelines

Since a signature means that you checked and verified that a certain public key belongs to a certain person who is in control of the accompanying private key, you need to follow these guidelines when signing peoples keys:

  • Keysigning is always done after meeting in person
  • During this meeting you hand each other your OpenPGP key fingerprint and at least one government issued ID with a photograph. These key fingerprints are usually distributed as key fingerprint slips, created by a script such as gpg-key2ps (package: signing-party)
  • You check whether the name on the key corresponds with the name on the ID and whether the person in front of you is indeed who he says he is.
  • Having done these two checks, you only need to check whether this person is in control of the private key. You do this by sending him/her back his/her signed public key, encrypted with his public key. The caff program makes this part very easy. You need to create a file named .caffrc in your homedir (only once) with the following content:
$CONFIG{owner} = q{Your full name here};
$CONFIG{email} = q{The emailaddress used in your key here};
$CONFIG{keyid} = [ qw{last 16 characters of your key fingerprint here} ];
Now you can simply run the following command:
caff key_id_of_other_persons_key
  • When you receive signed keys from others, you get them as attachment, save these attachments and import them with gpg. You can then send this signature to the keyservers so other people can know about it.
gpg --import filename_of_saved_signature
gpg --send-keys $GPGKEY

Signing Data

Signing data is helpful in verifying if the data from a person is indeed from that person. A typical scenario is described below.

Launchpad Key Signing

When you've set up GnuPG and have a key in the strong set, it is time to sign the Ubuntu Code Of Conduct if you want to become an Ubuntu member or Ubuntero. Signing is done in 3 easy steps:

gpg --clearsign UbuntuCodeofConduct-1.0.1.txt

OpenPGP Keys and Launchpad You need to tell Launchpad about your OpenPGP key(s) to be able to sign the Ubuntu Code of Conduct (and thus become an Ubuntero) and to build packages using HCT.

Visit the OpenPGP Keys page once logged into Launchpad. Paste your key fingerprint into the textbox:

gpg --fingerprint

Example: the key fingerprint would be something like "95BD 8377 2644 DD4F 28B5 2C37 0F6E 4CA6 D8FC 66D2"

Launchpad will send you and email which you will have to decrypt. You can save the text to a file and run

gpg --decrypt file.txt

You will need to enter your passphrase.

The message will be displayed along with the link you must follow to confirm your key in Launchpad.

Follow it, enter your Launchpad password as asked and you are done!

Signing and Encrypting Emails

This section addresses setting up your the Evolution and Thunderbird mail clients to sign and encrpyt your emails. Other email clients may be added to this list later.

Evolution

  • Open Evolution and go to Edit->Preferences.
  • Choose your email account, click on it, and then click Edit.
  • Click on the security tab.
  • In the PGP/GPG Key ID: box, paste the KEY-ID.
  • Click OK. Click Close.

If you want to use your key in any new email, simply click on the Security menu item in your new mail message, and then click on PGP Sign.

Mozilla Thunderbird

Install the Enigmail plugin either by:

sudo apt-get install mozilla-thunderbird-enigmail

or by downloading the plugin from here and install it manually.

Configure OpenPGP support in Thunderbird under: Enigmail->Preferences and add under GnuPG executable path the following path /usr/bin/gpg

Tips and Tricks

  • . Add your key to ~/.bashrc by adding a line similiar to export GPGKEY=YOUR-KEY-ID
  • . gnupg-agent and pinentry-gtk2 are packages that facilitate not having to enter the password for your key every time you want to use it. Open the file ~/.gnupg/gpg.conf in your favorite editor. Browse through it and change what you like. A few useful things to change are:
        • keyserver-options auto-key-retrieve
        • use-agent

The former makes gpg automatically retrieve gpg keys when verifying signatures. The latter makes you use gpg-agent, which is very useful if you use gpg a lot but don't like typing your password all the time.

Now create the file ~/.gnupg/gpg-agent.conf with the following content:

pinentry-program /usr/bin/pinentry-gtk-2
default-cache-ttl 86400
max-cache-ttl 86400

This will make gpg-agent use pinentry-gtk2 and it will remember your password for 24 hours. pinentry-gtk2 is not available in hoary, a backported breezy package can be found on http://seveas.ubuntulinux.nl/

GPG 2.0

GPG 2.0 is the new kid on the block. Now GPG 2.0 is aimed or done for the desktops rather than embedded or server which the previous version was for. The package needs to be installed & is in universe. Another difference is gpg 2.0 is now modular in nature. If you want to use gnupg2 with firepg firefox extension you better install gnupg2 first. Also consider using gpg2 for all the applications for which you were using gpg. While both of them can & do co-exist with each other its preferable to uninstall gpg before installing gpg2.

Now if you are going to use gpg2 for the same purposes as outlined above then just need to add 2 to the gpg command for e.g.

 
gpg2 --gen-key

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