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Contents
Introduction
The intent of this page is to explain how you can create and sign an OpenPGP key.
Then, to get connected to the web of trust, go to the keysigning coordination page.
How to
Tutorials explaining how to use GnuPG:
If you want your OpenPGP key signed by at least one (but ideally more than one) Debian Developer, you have to follow the below steps.
Step 1: Create a RSA keypair
gpg --full-gen-key
See also creating a keypair.
Note that due to weaknesses found with the SHA1 hashing algorithm Debian wants stronger RSA keys that are at least 4096 bits and preferring SHA2 although Ed25519 is even better.
Also see OpenPGP Best Practices, documentation about subkeys and migration off of SHA-1 key.
Step 2: Generate a revocation certificate
Generate also a revocation certificate if you already have one! Throughout the rest of the page, your fingerprint is assumed to be set in the variable ${myFingerPrint}
gpg --gen-revoke ${myFingerPrint} > ~/.gnupg/revocation-${myFingerPrint}.crt
Step 3: Make your public key public
gpg --send-key ${myFingerPrint}
Some public keyservers:
https://keyring.debian.org (only Debian Developers can upload or send key updates to this server)
https://keyserver.ubuntu.com (recommended)
https://keys.openpgp.org/ (used by Thunderbird)
Step 4: Print your key
The printout of your fingerprint must contain the following information:
- Your first name
- Your last name
- Your e-mail addresses (the ones you use with the key)
- The encryption method and the ID of the key (e.g. 4096R/1A2B3C4D5E6F7G8H)
- The fingerprint itself
You can use this function :
gpg -v --fingerprint ${myFingerPrint}
Usually, you make several printouts on a sheet of paper. It can for example be the size of a business card. You can also use the gpg-key2ps which is part of the signing-party package to create these printouts as:
gpg-key2ps -p a4 ${myFingerPrint} > out.ps
Alternatively, you can print in one column only to avoid printing issues (for extra wide keys):
gpg-key2ps -1 -p a4 ${myFingerPrint} > out.ps
If you go to a key signing party, you will have to send this information beforehand, and they will then print a list for each participant.
TIP: to read the out.ps file, you can use evince, okular, ghostscript or other ?PostScript viewer.
TIP2: Some websites also can be used to generate the PDF of OpenPGP fingerprint, such as: http://openpgp.quelltextlich.at/slip.html or http://keysheet.net
TIP3: if you would like a pdf instead of a postscript file you can pipe the gpg2ps output through ghostscript e.g.
gpg-key2ps -p a4 ${myFingerPrint} | gs -sDEVICE=pdfwrite -sOutputFile=out.pdf
Alternatively, you can show your fingerprint(s) on your laptop screen like this:
LANG=C gpg --list-secret-keys --fingerprint --keyid-format long | grep -Po 'fingerprint = \K.*' | sed 's/$/\n/; s/ /\n/' | /usr/games/sm -i -
Step 5: Hand out your key's fingerprint
The people who will sign your key will need to see some form of government issued ID (passport or similar).
You have to give the printout to at least one Debian Developer.
Read the official Debian keysigning page.
A CAcert member will need to see two IDs.
Step 6: Get your key digitally signed
The Debian Developer will with his ${ddSignersFingerprint} key, do the following:
- retrieve your key from the server
gpg --recv-keys ${myFingerPrint}
- verify that the information is correct (the fingerprint)
gpg --fingerprint ${myFingerPrint}
- sign it.
gpg --sign-key ${myFingerPrint}
- send it back to the key owner as an encrypted email (Do not send it directly to a server). Sending it encrypted is preferred as you can verify the person can decrypt the messages they receive.
gpg --armor --export ${myFingerPrint} | gpg --encrypt -r ${myFingerPrint} --armor --output ${myFingerPrint}-signedBy-${ddSignersFingerprint}.asc
Alternatively, the caff tool from the signing-party package automates all this process:
caff ${myFingerPrint}
Step 7: Send your signed key to the server
Some time after having participated in a keysigning, you will perhaps receive your signed key as an e-mail attachment. Import the signatures:
gpg -d ${myFingerPrint}-signedBy-${ddSignersFingerprint}.asc | gpg --import
Afterwards you will have to send your updated key to the server:
gpg --send-key ${ddSignersFingerprint}
Beyond Debian
Those interested in expanding the web of trust beyond Debian should visit:
See also