doc/md/GnuPG-signature.md

   1 ## Introduction
   2 ### PGP and GPG
   3 [Gnu Privacy Guard](https://gnupg.org/) (GnuPG) is an Open Source implementation of the
   4 [Pretty Good Privacy](https://en.wikipedia.org/wiki/Pretty_Good_Privacy#OpenPGP)
   5 (OpenPGP) specification. Its main purposes are digital authentication, signature and encryption.
   6
   7 It is often used by the [FLOSS](https://en.wikipedia.org/wiki/Free_and_open-source_software) community to verify:
   8
   9 - Linux package signatures: Debian [SecureApt](https://wiki.debian.org/SecureApt), ArchLinux [Master
  10 Keys](https://www.archlinux.org/master-keys/)
  11 - [SCM](https://en.wikipedia.org/wiki/Revision_control) releases & maintainer identity
  12
  13 ### Trust
  14 To quote Phil Pennock (the author of the [SKS](https://bitbucket.org/skskeyserver/sks-keyserver/wiki/Home) key server - http://sks.spodhuis.org/):
  15
  16 > You MUST understand that presence of data in the keyserver (pools) in no way connotes trust. Anyone can generate a key, with any name or email address, and upload it. All security and trust comes from evaluating security at the “object level”, via PGP Web-Of-Trust signatures. This keyserver makes it possible to retrieve keys, looking them up via various indices, but the collection of keys in this public pool is KNOWN to contain malicious and fraudulent keys. It is the common expectation of server operators that users understand this and use software which, like all known common OpenPGP implementations, evaluates trust accordingly. This expectation is so common that it is not normally explicitly stated.
  17
  18 Trust can be gained by having your key signed by other people (and signing their key back, too :) ), for instance during [key signing parties](https://en.wikipedia.org/wiki/Key_signing_party), see:
  19
  20 - [The Keysigning party HOWTO](http://www.cryptnet.net/fdp/crypto/keysigning_party/en/keysigning_party.html)
  21 - [Web of trust](https://en.wikipedia.org/wiki/Web_of_trust)
  22
  23 ## Generate a GPG key
  24 - [Generating a GPG key for Git tagging](http://stackoverflow.com/a/16725717) (StackOverflow)
  25 - [Generating a GPG key](https://help.github.com/articles/generating-a-gpg-key/) (GitHub)
  26
  27 ### gpg - provide identity information
  28 ```bash
  29 $ gpg --gen-key
  30
  31 gpg (GnuPG) 2.1.6; Copyright (C) 2015 Free Software Foundation, Inc.
  32 This is free software: you are free to change and redistribute it.
  33 There is NO WARRANTY, to the extent permitted by law.
  34
  35 Note: Use "gpg2 --full-gen-key" for a full featured key generation dialog.
  36
  37 GnuPG needs to construct a user ID to identify your key.
  38
  39 Real name: Marvin the Paranoid Android
  40 Email address: marvin@h2g2.net
  41 You selected this USER-ID:
  42     "Marvin the Paranoid Android <marvin@h2g2.net>"
  43
  44 Change (N)ame, (E)mail, or (O)kay/(Q)uit? o
  45 We need to generate a lot of random bytes. It is a good idea to perform
  46 some other action (type on the keyboard, move the mouse, utilize the
  47 disks) during the prime generation; this gives the random number
  48 generator a better chance to gain enough entropy.
  49 ```
  50
  51 ### gpg - entropy interlude
  52 At this point, you will:
  53 - be prompted for a secure password to protect your key (the input method will depend on your Desktop Environment and configuration)
  54 - be asked to use your machine's input devices (mouse, keyboard, etc.) to generate random entropy; this step _may take some time_
  55
  56 ### gpg - key creation confirmation
  57 ```bash
  58 gpg: key A9D53A3E marked as ultimately trusted
  59 public and secret key created and signed.
  60
  61 gpg: checking the trustdb
  62 gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
  63 gpg: depth: 0  valid:   2  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 2u
  64 pub   rsa2048/A9D53A3E 2015-07-31
  65       Key fingerprint = AF2A 5381 E54B 2FD2 14C4  A9A3 0E35 ACA4 A9D5 3A3E
  66 uid       [ultimate] Marvin the Paranoid Android <marvin@h2g2.net>
  67 sub   rsa2048/8C0EACF1 2015-07-31
  68 ```
  69
  70 ### gpg - submit your public key to a PGP server (Optional)
  71 ``` bash
  72 $ gpg --keyserver pgp.mit.edu --send-keys A9D53A3E
  73 gpg: sending key A9D53A3E to hkp server pgp.mit.edu
  74 ```
  75
  76 ## Create and push a GPG-signed tag
  77
  78 See [Release Shaarli](Release Shaarli).