DeveloperWiki:Managing the Master Key

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Revision as of 20:30, 18 November 2011 by Pierre (Talk | contribs) (Creating the master key)

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Prepare your Smartcard

Install the ccid package and start the pcscd daemon. Insert your smartcard reader and check the output of gpg --card-status

Creating the master key

Run gpg --card-edit. Type in admin to enabled administration functions. All available commands can now be listed by issuing the help command. Use the name and sex commands to set some unimportant meta data.

To create a new key pair just type in generate. Create a 3072 Bits key that does not expire and enter your data according to this example:

Real name: Pierre Schmitz
Email address:
Comment: Arch Linux Master Key

Confirm that your USER-ID looks like "Pierre Schmitz (Arch Linux Master Key) <>". Generating the key will take some time. Note that the encryption key will be reduced to 1024 Bits.

If you created a backup of your key during creation you should secure it on an offline device and remove the key from your hard drive. E.g. use shred:

shred -u /home/pierre/.gnupg/sk_8DFDBF1F86872C2F.gpg

Signing the master key

Revoking a master key

Signing developer keys

Revoking developer keys

Open questions

  • Using the smartcard generates following errors without any apparent effect:
libusb couldn't open USB device /dev/bus/usb/001/006: Permission denied.
libusb requires write access to USB device nodes.

Cause: gnupg has an internal ccid driver. This driver accesses the USB device node directly, without going through pcscd. However, gnupg's internal driver does not support the Gemalto USB reader anyway, so this message can be ignored.

  • udev/packaging issue:
udevd[273]: specified group 'pcscd' unknown

This is unproblematic: the pcscd daemon runs as root.

  • Should we advice to create a backup during key creation or rather not?
  • Is the passphrase only used for the backup key?
  • Is the public key also stored on the card?

It probably is, but there is no apparent way to obtain it. Export it to some keyserver quickly.

  • How should the url configuration be set?

A string pointing to a URL that stores your pubkey.

  • What is the impact of setting forcesig?

If you enable forcesig, you must enter the PIN for each single signature. This is recommended.

External documentation