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WIP (Ctrl-S's job)
WIP (Ctrl-S's job)


Guide for securely creating a PGP keyset.
Guide for securely creating a PGP keyset.
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Some smartcards support longer keys.
Some smartcards support longer keys.
This guide will use 2048 bit RSA keys for as much security as is currently practical.
This guide will use 2048 bit RSA keys for as much security as is currently practical.




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# Let machine boot into persistant liveusb
# Let machine boot into persistant liveusb
# Ubuntu desktop environment should be displayed on your computer.
# Ubuntu desktop environment should be displayed on your computer.


=== Update liveUSB software ===
=== Update liveUSB software ===
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</syntaxhighlight>
</syntaxhighlight>


This is an example of expected output with a yubikey 5 with values removed for confidentiality:
<syntaxhighlight lang="bash">
$ gpg --card-edit list


Reader ...........: [REMOVED]
Application ID ...: [REMOVED]
Version ..........: 3.4
Manufacturer .....: Yubico
Serial number ....: [REMOVED]
Name of cardholder: [not set]
Language prefs ...: [not set]
Sex ..............: unspecified
URL of public key : [not set]
Login data .......: [not set]
Signature PIN ....: not forced
Key attributes ...: rsa2048 rsa2048 rsa2048
Max. PIN lengths .: 127 127 127
PIN retry counter : 3 0 3
Signature counter : 0
KDF setting ......: on
Signature key ....: [none]
Encryption key....: [none]
Authentication key: [none]
General key info..: [none]


gpg/card>
</syntaxhighlight>


== Remove machine from network ==
== Remove machine from network ==
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</syntaxhighlight>
</syntaxhighlight>
* You should fail to connect.
* You should fail to connect.


== Generate keys ==
== Generate keys ==
* !!! BE OFFLINE !!!
* !!! BE OFFLINE !!!
=== Smartcard PIN codes ===
* You need to set two PIN codes for your smartcard.
<br>A user PIN and an admin PIN
* Generate a random number to use as a PIN for your smartcard
(apg is a linux tool to generate random passwords https://linux.die.net/man/1/apg )
<syntaxhighlight lang="bash">
## apg (Password generator program)
## -a 1 (Use supplied parameters)
## -M N (Use numerals only)
## -m 10 (Minimum 8 characters long)
## -x 10 (Maximum 8 characters long)
$ apg -a 1 -M N -m 8 -x 8
86187171
65856553
45100116
18826756
02283057
10274420
</syntaxhighlight>
* Write down the user PIN code on your paper.
<code>User PIN: USER-PIN-HERE</code>
<br>The user PIN is required to use the stored keys.
* Write down the admin PIN code on your paper.
<code>admin PIN: ADMIN-PIN-HERE</code>
<br>The admin pin is used to edit the card.
* Store copies of these codes in safe places where you will not lose them and nobody can read them.
* You will not be able to use the smartcard without the correct code.
* Change the smartcard's user PIN.
<syntaxhighlight lang="bash">
$ gpg --card-edit
gpg/card> admin ## Card admin menu.
gpg/card> passwd ## Change card password(s).
gpg/card> 1 ## 1 - change PIN.
gpg/card> q ## Exit PIN edit submenu.
gpg/card> list ## Display card information.
gpg/card> quit ## Exit GPG.
</syntaxhighlight>
* Change the smartcard's admin PIN
<syntaxhighlight lang="bash">
$ gpg --card-edit
gpg/card> admin ## Card admin menu.
gpg/card> passwd ## Change card password(s).
gpg/card> 3 ## 3 - change Admin PIN.
gpg/card> q ## Exit PIN edit submenu.
gpg/card> list ## Display card information.
gpg/card> quit ## Exit GPG.
</syntaxhighlight>
=== GPG Secret keys ===
=== GPG Secret keys ===
* Create master as demonstrated in the following example:
* Create master as demonstrated in the following example:
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generator a better chance to gain enough entropy.
generator a better chance to gain enough entropy.


sec  rsa4096/FEEDB00BCODEBEEF
sec  rsa4096/BEBEAAF16847B703
     created: 2020-02-12  expires: never      usage: SC
     created: 2020-02-12  expires: never      usage: SC
     trust: ultimate      validity: ultimate
     trust: ultimate      validity: ultimate
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</syntaxhighlight>
</syntaxhighlight>


=== Store keys to backup drives ===
 
== Store keys to backup drives ==
* !!! BE OFFLINE !!!
* !!! BE OFFLINE !!!
* Create a folder to store our secret keys:
* Create a folder to store our secret keys:
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$ cd '/medua/ubuntu/keystore01/gpg.ctrl-s.2020-02-01'
$ cd '/medua/ubuntu/keystore01/gpg.ctrl-s.2020-02-01'
</syntaxhighlight>
</syntaxhighlight>


* Secret keys:
* Secret keys:
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</syntaxhighlight>
</syntaxhighlight>


* SSH public key
<syntaxhighlight lang="bash">
$ date; gpg --output "FEEDB00BCODEBEEF-1970JAN01.ssh-remote.key" --armour --export-ssh-key FEEDB00BCODEBEEF
</syntaxhighlight>
== Exporting SSH key ==
How to generate the ssh public key to put onto a remote server.
<syntaxhighlight lang="bash">
$ date; gpg --output "FEEDB00BCODEBEEF-1970JAN01.ssh-remote.key" --armour --export-ssh-key FEEDB00BCODEBEEF
</syntaxhighlight>
== Smartcards ==
== Reset smartcard to factory settings and erase stored  GPG keys ==
* ! ONLY TESTED ON Yubikey 5 !
* ! USE AT OWN RISK !
* I don't know if doing a factory reset will affect other functions of your smartcard, such as FIDO, FIDO2, PIV, OTP, etc.
<syntaxhighlight lang="bash">
$ date; gpg --card-edit # Begin editing the smartcard.
gpg/card> help # Show commands list.
## Inspect card to be sure it's the one you intend to reset:
gpg/card> list # "list all available data"
gpg/card> admin # Enable card admin commands.
gpg/card> help # Show commands list.
## Perform factory reset on smartcard to bring it to a known-good state
gpg/card> factory-reset # "factory-reset  destroy all keys and data"
## Confirm that you want to reset the card
>y
>yes
## Confirm card has been reset by inspection:
gpg/card> list # "list all available data"
gpg/card>quit
</syntaxhighlight>
=== Set the smartcard PIN, adminPIN, & reset code ===
*The PIN, AdminPIN, and ResetCode can be alphanumerical passphrases.
  (a-z, A-Z, 0-9, space, etc.)
* "PIN" - Day-to-day use.
* "Admin PIN" - Load new key onto card.
* "Reset Code" - Reset PIN attempts counter.
* The Default yubikey "PIN" is "123456"
* The Default Yubikey "Admin PIN" apin is "12345678"
* Begin editing the smartcard.
<syntaxhighlight lang="bash">
$ date; gpg --card-edit # Begin editing the smartcard.
gpg/card> admin
</syntaxhighlight>
* Set PIN
<syntaxhighlight lang="bash">
gpg/card> passwd # "menu to change or unblock the PIN"
>"1 - change PIN"
</syntaxhighlight>
* Set admin PIN (used for installing secret key to card)
<syntaxhighlight lang="bash">
gpg/card> passwd # "menu to change or unblock the PIN"
>3 - change Admin PIN
</syntaxhighlight>
* Set the Recovery Code (Used for resetting retry counter for PIN)
<syntaxhighlight lang="bash">
gpg/card> passwd # "menu to change or unblock the PIN"
>4 - set the Reset Code
</syntaxhighlight>
=== Smartcard PIN codes ===
* You need to set two PIN codes for your smartcard.
<br>A user PIN and an admin PIN
* Generate a random number to use as a PIN for your smartcard
(apg is a linux tool to generate random passwords https://linux.die.net/man/1/apg )
<syntaxhighlight lang="bash">
## apg (Password generator program)
## -a 1 (Use supplied parameters)
## -M N (Use numerals only)
## -m 10 (Minimum 8 characters long)
## -x 10 (Maximum 8 characters long)
$ apg -a 1 -M N -m 8 -x 8
86187171
65856553
45100116
18826756
02283057
10274420
</syntaxhighlight>
* Write down the user PIN code on your paper.
<code>User PIN: USER-PIN-HERE</code>
<br>The user PIN is required to use the stored keys.
* Write down the admin PIN code on your paper.
<code>admin PIN: ADMIN-PIN-HERE</code>
<br>The admin pin is used to edit the card.
* Store copies of these codes in safe places where you will not lose them and nobody can read them.
* You will not be able to use the smartcard without the correct code.
* Change the smartcard's user PIN.
<syntaxhighlight lang="bash">
$ gpg --card-edit
gpg/card> admin ## Card admin menu.
gpg/card> passwd ## Change card password(s).
gpg/card> 1 ## 1 - change PIN.
gpg/card> q ## Exit PIN edit submenu.
gpg/card> list ## Display card information.
gpg/card> quit ## Exit GPG.
</syntaxhighlight>
* Change the smartcard's admin PIN
<syntaxhighlight lang="bash">
$ gpg --card-edit
gpg/card> admin ## Card admin menu.
gpg/card> passwd ## Change card password(s).
gpg/card> 3 ## 3 - change Admin PIN.
gpg/card> q ## Exit PIN edit submenu.
gpg/card> list ## Display card information.
gpg/card> quit ## Exit GPG.
</syntaxhighlight>
=== Reload the secret key and subkeys from the backup file ===
This is required if you want to prepare more than one smartcard.
==== Delete GPG keystore ====
* Do not do this unless you are sure you have successfully backed up your keys.
* To install the same key to additional smartcards, it must be reloaded from the file again.
* It MAY be needed to delete the key from GPG's keystore for reimport?
<syntaxhighlight lang="bash">
$ date; gpg --delete-secret-keys FEEDB00BCODEBEEF # Forget/erase secret key from GPG keystore.
$ date; gpg --delete-keys FEEDB00BCODEBEEF # Forget/erase public key from GPG keystore.
$ date; rm -rf ~/.gnupg/ # Erase GPG keystore alltogether.
</syntaxhighlight>
==== Import secret key from file ====
<syntaxhighlight lang="bash">
$ cd "/path/to/my/key/backup/dir/" # Go to the directory where we have the key files.
$ date; gpg --import FEEDB00BCODEBEEF.1970JAN01.public.key # Import your publickey from file.
$ date; gpg --allow-secret-key-import --import FEEDB00BCODEBEEF-20200530.masterkeys.txt # Import your secretkey from file into local keystore (You should be asked for the secretkey password at this point).
$ date; gpg --allow-secret-key-import --import FEEDB00BCODEBEEF-20200530.subkeys.txt
</syntaxhighlight>


==== Set imported secretkey to maximum trust level ====
* It is required to set the trust level to ultimate to put it on a smartcard.
<syntaxhighlight lang="bash">
$ date; gpg --edit-key FEEDB00BCODEBEEF
gpg>trust # Edit trust level for the key.
gpg>trust>5 # "5 = I trust ultimately"
gpg>trust>y # Confirm absolute trust
gpg>save # Save changes and exit GPG.
</syntaxhighlight>


=== Move the key to smartcard ===
=== Move the key to smartcard ===
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</syntaxhighlight>
</syntaxhighlight>


== Erase keys from liveusb ==
 
=== Erase keys from liveusb ===
* !!! BE OFFLINE !!!
* !!! BE OFFLINE !!!
* Remove the GPG keystore as an added precaution.
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
$ rm -rf ~/.gnupg*
$ rm -rf /.gnupg*
</syntaxhighlight>
<syntaxhighlight lang="bash">
## TODO
</syntaxhighlight>
</syntaxhighlight>


=== Setup public key side ===
Copy and paste the text in the ssh-remote.key file from the earlier steps into the `~/.ssh/authorized_keys` file on the machine you intend to connect to.




=== Set up key on machine we want to SSH to ===
Open the authorized_keys for your user account and paste in the SSH key
(Created earlier in this guide as "FEEDB00BCODEBEEF-1970JAN01.ssh-remote.key")
<syntaxhighlight lang="bash">
$ mkdir -vp ~/.ssh/ ; touch ~/.ssh/authorized_keys; # Create authorized_keys if it does not exist.
$ nano ~/.ssh/authorized_keys # Edit authorized_keys file
</syntaxhighlight>


== Using multiple cards ==
=== Setup public key side ===
This command tells GPG to associate keys it has with copies of those keys on a connected smartcard.
The same command works on both Linux and Windows.
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
$ gpg-connect-agent "scd serialno" "learn --force" /bye
## TODO
</syntaxhighlight>
<syntaxhighlight lang="cmd">
> gpg-connect-agent "scd serialno" "learn --force" /bye
</syntaxhighlight>
</syntaxhighlight>
https://github.com/drduh/YubiKey-Guide#using-multiple-keys


 
=== Set up key on machine we want to SSH to ===
== WSL  (Windows Subsystem for Linux) ==
* ! WIP !
Getting SSH to work in WSL.
https://github.com/drduh/YubiKey-Guide#using-multiple-keys
https://github.com/vuori/weasel-pageant
* Download and extract weasel-pagent to somewhere convenient on the windows side.
https://github.com/vuori/weasel-pageant/releases
Place this line in your .bashrc file
<syntaxhighlight lang="bash">$ nano ~./bashrc</syntaxhighlight>
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Make GNUPG / GPG work with windows smartcards weasel-pageant
## TODO
eval $(<location where you unpacked the zip>/weasel-pageant -rb -a $HOME/.weasel-pageant.sock)
</syntaxhighlight>
Reload the config from the updated file:
<syntaxhighlight lang="bash">$ source ~/.bashrc</syntaxhighlight>
Add entry to the ~/.ssh/config file:
<syntaxhighlight lang="bash">nano ~/.ssh/config</syntaxhighlight>
<syntaxhighlight lang="bash">
ForwardAgent yes
RemoteForward /root/.gnupg/S.gpg-agent.ssh $HOME/.weasel-pageant.sock
</syntaxhighlight>
<syntaxhighlight lang="bash">$ chmod 600 ~/.ssh/config ; chown $USER ~/.ssh/config # Ensure you have the correct owner and permissions for the config file.</syntaxhighlight>
Test if it works:
<syntaxhighlight lang="bash">$ ssh-add -l</syntaxhighlight>
If it is working it will show your key in the list it gives.
 
if you get the erro :
chmod 600 ~/.ssh/config
=== Automating on Windows ===
Save the following script to a .bat file. (e.g.  `C:\scripts\gpg_refresh.bat`)
<syntaxhighlight lang="cmd">
@echo off
rem gpg_refresh.bat
rem Check if our key is on an attached smartcard and associate it if so.
gpg-connect-agent "scd serialno" "learn --force" /bye
</syntaxhighlight>
 
* Press the start button on your keyboard to open the start menu.
* Type "schedule", "Task Scheduler" should appear as a search result in the start menu.
* Open Task Scheduler.
* In the section on the right of the window (Under the heading "Actions") select "Create Task".
* Set the Name to `Check and Update GPG smartcards`
* Set the description to `Tell GPG to compare its keys against smartcards, and link any that match.`
** "Name" : "1 hour"
** "Description" : "1 hour"
** "Security options" -> "Run whether user is logged on or not" : Selected. (Hides command window when task runs)
** "Security options" -> "Do not store password. The task will only have access to local computer resources." : Selected. (Prevents requiring user's password to be entered to set up task.)
* This task must be running using your user account, so that the instance of GPG associated with your account is acted on.
** "Configure for:": "Windows 10"
 
* Click on the "Triggers" tab at the top of the window then click the "New" button
* In the "New Trigger" window that opens:
** "Begin the task": `On a schedule`
** Settings -> "Daily" selected.
** Settings -> "Start": Set a value in the next hour or so.
** Settings -> "Recur every" [ ] days: "1"
** "Advanced setings" -> "Repeat task every": Box checked.
** "Advanced setings" -> "Repeat task every" : "1 hour"
** "Advanced setings" -> "for a duration of" : "1 day"
** "Advanced setings" -> "Expire": Box unchecked. (Never expire)
** "Advanced setings" -> "Enabled": Box checked.
* Click "OK" once these settings are set.
 
* Click on the "Actions" tab at the top of the window then click the "New" button
* In the "New Action" window that opens:
** "Settings` -> "Action": "Start a program"
** "Settings" -> "Program/script" : The path to the .bat file.
* Click "OK" once these settings are set.
 
* Click "OK" in the "Create Task" window.
 
https://stackoverflow.com/questions/4249542/run-a-task-every-x-minutes-with-windows-task-scheduler
 
https://www.howtogeek.com/tips/how-to-run-a-scheduled-task-without-a-command-window-appearing/
 
== Troubleshooting ==
To kill running background  GPG:
<syntaxhighlight lang="cmd">
gpg-connect-agent killagent /bye # Kill GPG.
</syntaxhighlight>
</syntaxhighlight>


To start background GPG:
<syntaxhighlight lang="cmd">
gpg-connect-agent /bye # Start GPG.
</syntaxhighlight>


To inspect connected card(s?):
<syntaxhighlight lang="cmd">
gpg --card-status # Inspect smartcard.
</syntaxhighlight>


== Sources ==
== Sources ==
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https://msol.io/blog/tech/back-up-your-pgp-keys-with-gpg/
https://msol.io/blog/tech/back-up-your-pgp-keys-with-gpg/
* Other guides:
https://github.com/tomlowenthal/documentation/blob/master/gpg/smartcard-keygen.md
https://blogs.fsfe.org/jens.lechtenboerger/2013/04/19/how-to-set-up-your-fellowship-card/
https://gist.github.com/ageis/14adc308087859e199912b4c79c4aaa4
https://spin.atomicobject.com/2013/11/24/secure-gpg-keys-guide/
https://support.yubico.com/support/solutions/articles/15000006420-using-your-yubikey-with-openpgp
https://www.linode.com/docs/security/authentication/gpg-key-for-ssh-authentication/
https://0day.work/using-a-yubikey-for-gpg-and-ssh/
https://xladius.com/opsec/2018/06/25/using-yubikeys-for-openpgp
https://oychang.com/posts/gpg/notes-on-yubikey-neo.html
https://github.com/drduh/YubiKey-Guide
* Misc of interest:
https://www.dongleauth.info/
https://www.dongleauth.info/dongles/
https://www.nitrokey.com/documentation/installation
https://www.nitrokey.com/documentation/frequently-asked-questions-faq#how-to-use-the-nitrokey-with-multiple-computers
https://www.fsij.org/doc-gnuk/gnuk-passphrase-setting.html#
https://security.stackexchange.com/questions/45094/smart-card-gnupg-what-is-stored-in-my-keyring-how-to-adopt-smart-card
https://stackoverflow.com/questions/46689885/how-to-get-public-key-from-an-openpgp-smart-card-without-using-key-servers
https://www.gnupg.org/howtos/card-howto/en/smartcard-howto-single.html
https://crypto.stackexchange.com/questions/43223/are-additional-pgp-subkeys-still-needed-for-smartcards
https://stackoverflow.com/questions/48016033/how-do-i-encrypt-an-email-using-a-yubikey
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