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GNUPG - WHAT’S NEW IN 2.1
Werner Koch
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2017-08-28
Table of Contents ─────────────────
1 What’s new in GnuPG 2.1 .. 1.1 Removal of the secret keyring .. 1.2 Removal of PGP-2 support .. 1.3 Leaner key generation interface .. 1.4 Support for ECC .. 1.5 Quick generate and sign commands .. 1.6 Improved Pinentry support .. 1.7 Auto-start of the gpg-agent .. 1.8 Duplicate long key id fixes .. 1.9 Enhanced Dirmngr .. 1.10 Better keyserver pool support .. 1.11 Faster keyring format .. 1.12 Auto-generated revocation certificates .. 1.13 Improved card support .. 1.14 New format for key listings .. 1.15 Recipient key from file .. 1.16 Using gpg as a filter .. 1.17 Support for Putty .. 1.18 Export of SSH public keys .. 1.19 Improved X.509 certificate creation .. 1.20 Scripts to create a Windows installer
A possibly revised version of this article can be found at: https://gnupg.org/faq/whats-new-in-2.1.html
1 What’s new in GnuPG 2.1 ═════════════════════════
GnuPG version 2.1 (now known as 2.2) comes with a bag of new features which changes some things old-timers are used to. This page explains the more important ones. It expects that the reader is familiar with GnuPG version 2.0 and aware that GnuPG consists of /gpg/, /gpgsm/, and /gpg-agent/ as its main components.
• The file /secring.gpg/ is not anymore used to store the secret keys. Merging of secret keys is now supported.
• All support for /PGP-2 keys/ has been removed for security reasons.
• The standard key generation interface is now much leaner. This will help a new user to quickly generate a suitable key.
• Support for /Elliptic Curve Cryptography/ (ECC) is now available.
• Commands to create and sign keys from the command line without any extra prompts are now available.
• The Pinentry may now show the new passphrase entry and the passphrase confirmation entry in one dialog.
• There is no more need to manually start the gpg-agent. It is now started by any part of GnuPG as needed.
• Problems with importing keys with the same long key id have been addressed.
• The /dirmngr/ is now part of GnuPG proper and also takes care of accessing keyserver.
• Keyserver pools are now handled in a smarter way.
• A new format for locally storing the public keys is now used. This considerable speeds up operations on large keyrings.
• /Revocation certificates/ are now created by default.
• Card support has been updated, new readers and token types are supported.
• The format of the key listing has been changed to better identify the properties of a key.
• A file with the recipient’s key may now be used directly.
• Gpg can be used to filter out parts of a key.
• The gpg-agent may now be used on Windows as /pageant/ replacement for /putty/ in the same way it is used for years on Unix as /ssh-agent/ replacement.
• Creation of X.509 certificates has been improved. It is now also possible to export them directly in PKCS#8 and PEM format for use on TLS servers.
• Export of /ssh/ keys has been integrated.
• The scripts to create a Windows installer are now part of GnuPG.
Now for the detailed description of these new features. Note that the examples assume that /gpg/ is installed as /gpg/. Your installation may have it installed under the name /gpg2/.
1.1 Removal of the secret keyring ─────────────────────────────────
gpg used to keep the public key pairs in two files: pubring.gpg' and secring.gpg'. The only difference is that secring stored in addition
to the public part also the private part of the key pair. The secret
keyring thus contained only the keys for which a private key is
available, that is the user’s key. It required a lot of code to keep
both versions of the key in sync and led to sometimes surprising
inconsistencies.
The design of GnuPG-2 demands that only the gpg-agent has control over the private parts of the keys and the actual encryption engine (gpg or gpgsm) does not know about the private key but care only about session keys and keys for symmetric encryption. This has been implemented about 10 years ago for /gpgsm/ (the S/MIME part of GnuPG). However, /gpg/ (the OpenPGP part) used the gpg-agent only as passphrase entry and cache device but handles the private key itself.
With GnuPG 2.1 this changed and /gpg/ now also delegates all private key operations to the gpg-agent. Thus there is no more code in the /gpg/ binary for handling private keys. En passant this allows the long time requested “merging of secret keys” and several other advanced key management techniques.
To ease the migration to the no-secring method, /gpg/ detects the
presence of a secring.gpg' and converts the keys on-the-fly to the the key store of /gpg-agent/ (this is the private-keys-v1.d'
directory below the GnuPG home directory (~/.gnupg')). This is done only once and an existing secring.gpg' is then not anymore touched by
/gpg/. This allows co-existence of older GnuPG versions with GnuPG
2.1. However, any change to the private keys using the new /gpg/ will
not show up when using pre-2.1 versions of GnuPG and vice versa.
Note that the command `--export-secret-keys' still creates an OpenPGP compliant file with the secret keys. This is achieved by asking /gpg-agent/ to convert a key and return it in the OpenPGP protected format. The export operation requires that the passphrase for the key is entered so that /gpg-agent/ is able to change the protection from its internal format to the OpenPGP required format.
1.2 Removal of PGP-2 support ────────────────────────────
Some algorithms and parts of the protocols as used by the 20 years old [PGP-2] software are meanwhile considered unsafe. In particular the baked in use of the [MD5] hash algorithm limits the security of PGP-2 keys to non-acceptable rate. Technically those PGP-2 keys are called version 3 keys (v3) and are easily identified by a shorter fingerprint which is commonly presented as 16 separate double hex digits.
With GnuPG 2.1 all support for those keys has gone. If they are in an existing keyring they will eventually be removed. If GnuPG encounters such a key on import it will not be imported due to the not anymore implemented v3 key format. Removing the v3 key support also reduces complexity of the code and is thus better than to keep on handling them with a specific error message.
There is one use case where PGP-2 keys may still be required: For existing encrypted data. We suggest to keep a version of GnuPG 1.4 around which still has support for these keys (it might be required to use the `--allow-weak-digest-algos' option). A better solution is to re-encrypt the data using a modern key.
[PGP-2] https://en.wikipedia.org/wiki/Pretty_Good_Privacy
[MD5] https://en.wikipedia.org/wiki/MD5
1.3 Leaner key generation interface ───────────────────────────────────
This is best shown with an example:
┌──── │ $ gpg --gen-key │ gpg (GnuPG) 2.1.0; Copyright (C) 2014 Free Software Foundation, Inc. │ This is free software: you are free to change and redistribute it. │ There is NO WARRANTY, to the extent permitted by law. │ │ gpg: keybox '/home/foo/.gnupg/pubring.kbx' created │ Note: Use "gpg --full-gen-key" for a full featured key generation dialog. │ │ GnuPG needs to construct a user ID to identify your key. │ │ Real name: Glenn Greenwald │ Email address: glenn@example.org │ You selected this USER-ID: │ "Glenn Greenwald glenn@example.org" │ │ Change (N)ame, (E)mail, or (O)kay/(Q)uit? o │ [...] │ pub rsa2048/68FD0088 2014-11-03 │ Key fingerprint = 0290 5ABF 17C7 81FB C390 9B00 636A 1BBD 68FD 0088 │ uid [ultimate] Glenn Greenwald glenn@example.org │ sub rsa2048/84439DCD 2014-11-03 └────
Thus only the name and the mail address are required. For all other parameters the default values are used. Many graphical frontends works in the same way. Note that /gpg/ prints a hint for the old time gpg users on how to get the full option menu.
1.4 Support for ECC ───────────────────
GnuPG now support Elliptic Curve keys for public key encryption. This is defined in [RFC-6637]. Because there is no other mainstream OpenPGP implementation yet available which supports ECC, the use of such keys is still very limited. Thus GnuPG 2.1 currently hides the options to create an ECC key.
For those who want to experiment with ECC or already want to prepare a
key for future use, the command --full-gen-key' along with the option --expert' is the enabler:
┌──── │ $ gpg --expert --full-gen-key │ gpg (GnuPG) 2.1.0; Copyright (C) 2014 Free Software Foundation, Inc. │ This is free software: you are free to change and redistribute it. │ There is NO WARRANTY, to the extent permitted by law. │ │ Please select what kind of key you want: │ (1) RSA and RSA (default) │ (2) DSA and Elgamal │ (3) DSA (sign only) │ (4) RSA (sign only) │ (7) DSA (set your own capabilities) │ (8) RSA (set your own capabilities) │ (9) ECC and ECC │ (10) ECC (sign only) │ (11) ECC (set your own capabilities) │ Your selection? 9 │ Please select which elliptic curve you want: │ (2) NIST P-256 │ (3) NIST P-384 │ (4) NIST P-521 │ (5) Brainpool P-256 │ (6) Brainpool P-384 │ (7) Brainpool P-512 │ Your selection? 2 │ Please specify how long the key should be valid. │ 0 = key does not expire │ = key expires in n days │ w = key expires in n weeks │ m = key expires in n months │ y = key expires in n years │ Key is valid for? (0) │ Key does not expire at all │ Is this correct? (y/N) y │ │ GnuPG needs to construct a user ID to identify your key. │ │ Real name: Edward Snowden │ Email address: edward@example.org │ Comment: │ You selected this USER-ID: │ "Edward Snowden edward@example.org" │ │ Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o │ [...] │ pub nistp256/382660E3 2014-11-03 │ Key fingerprint = E630 27CF 3D68 22A7 6FF2 093E D179 9E72 3826 60E3 │ uid [ultimate] Edward Snowden edward@example.org │ sub nistp256/48C9A997 2014-11-03 nistp256 └────
In this example we created a primary ECC key for signing and an subkey for encryption. For both we use the NIST P-256 curve. The key may now be used in the same way as any other key. It is possible to add an RSA subkey or one can create an RSA or DSA main key and add an ECC subkey for signing or encryption. Note that the list of offered curves depends on the installed Libgcrypt version.
For many people the NIST and also the Brainpool curves have an doubtful origin and thus the plan for GnuPG is to use Bernstein’s [Curve 25519] as default. GnuPG 2.1.0 already comes with support for signing keys using the [Ed25519] variant of this curve. This has not yet been standardized by the IETF (i.e. there is no RFC) but we won’t wait any longer and go ahead using the proposed format for this signing algorithm. The format for an encryption key has not yet been finalized and will be added to GnuPG in one of the next point releases. Recall that an encryption subkey can be added to a key at any time. If you want to create a signing key you may do it this way:
┌──── │ $ gpg --expert --full-gen-key │ gpg (GnuPG) 2.1.0; Copyright (C) 2014 Free Software Foundation, Inc. │ This is free software: you are free to change and redistribute it. │ There is NO WARRANTY, to the extent permitted by law. │ │ Please select what kind of key you want: │ (1) RSA and RSA (default) │ (2) DSA and Elgamal │ (3) DSA (sign only) │ (4) RSA (sign only) │ (7) DSA (set your own capabilities) │ (8) RSA (set your own capabilities) │ (9) ECC and ECC │ (10) ECC (sign only) │ (11) ECC (set your own capabilities) │ Your selection? 10 │ Please select which elliptic curve you want: │ (1) Curve 25519 │ (2) NIST P-256 │ (3) NIST P-384 │ (4) NIST P-521 │ (5) Brainpool P-256 │ (6) Brainpool P-384 │ (7) Brainpool P-512 │ Your selection? 1 │ gpg: WARNING: Curve25519 is not yet part of the OpenPGP standard. │ Use this curve anyway? (y/N) y │ Please specify how long the key should be valid. │ 0 = key does not expire │ = key expires in n days │ w = key expires in n weeks │ m = key expires in n months │ y = key expires in n years │ Key is valid for? (0) │ Key does not expire at all │ Is this correct? (y/N) y │ │ GnuPG needs to construct a user ID to identify your key. │ │ Real name: Laura Poitras │ Email address: laura@example.org │ Comment: │ You selected this USER-ID: │ "Laura Poitras laura@example.org" │ │ Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o │ [...] │ pub ed25519/5C1AFC2A 2014-11-03 │ Key fingerprint = ED85 4D98 5D8F 502F C6C5 FFB2 AA81 319E 5C1A FC2A │ uid [ultimate] Laura Poitras laura@example.org └────
Support for ECC keys is available only on some keyservers but it is expected that this will be fixed over the next few months.
[RFC-6637] https://rfc-editor.org/info/rfc6637
[Curve 25519] http://cr.yp.to/ecdh/curve25519-20060209.pdf
[Ed25519] http://dx.doi.org/10.1007/s13389-012-0027-1
1.5 Quick generate and sign commands ────────────────────────────────────
Sometimes it is useful to use only command line options without any parameter file or interactive prompts for generating a key or to sign a key. This can now be accomplished with a few new commands:
┌──── │ $ gpg --batch --quick-gen-key 'Daniel Ellsberg ellsberg@example.org' │ gpg: key 911B90A9 marked as ultimately trusted └────
If a key with that user id already exists, gpg bails out with an error
message. You can force creation using the option --yes'. If you want some more control, you may not use --batch' and gpg will ask for
confirmation and show the resulting key:
┌──── │ $ gpg --quick-gen-key 'Daniel Ellsberg ellsberg@example.org' │ About to create a key for: │ "Daniel Ellsberg ellsberg@example.org" │ │ Continue? (Y/n) y │ gpg: A key for "Daniel Ellsberg ellsberg@example.org" already exists │ Create anyway? (y/N) y │ gpg: creating anyway │ [...] │ pub rsa2048/BD19AC1C 2014-11-04 │ Key fingerprint = 15CB 723E 2000 A1A8 2505 F3B7 CC00 B501 BD19 AC1C │ uid [ultimate] Daniel Ellsberg ellsberg@example.org │ sub rsa2048/72A4D018 2014-11-04 └────
Another common operation is to sign a key. /gpg/ can do this directly from the command line by giving the fingerprint of the to-be-signed key:
┌──── │ $ gpg --quick-sign-key '15CB 723E 2000 A1A8 2505 F3B7 CC00 B501 BD19 AC1C' │ │ pub rsa2048/BD19AC1C │ created: 2014-11-04 expires: never usage: SC │ trust: ultimate validity: ultimate │ Primary key fingerprint: 15CB 723E 2000 A1A8 2505 F3B7 CC00 B501 BD19 AC1C │ │ Daniel Ellsberg ellsberg@example.org └────
In case the key has already been signed, the command prints a note and exits with success. In case you want to check that it really worked, use `--check-sigs' as usual:
┌──── │ $ gpg --check-sigs '15CB 723E 2000 A1A8 2505 F3B7 CC00 B501 BD19 AC1C' │ gpg: checking the trustdb │ gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model │ gpg: depth: 0 valid: 6 signed: 1 trust: 0-, 0q, 0n, 0m, 0f, 6u │ pub rsa2048/BD19AC1C 2014-11-04 │ uid [ full ] Daniel Ellsberg ellsberg@example.org │ sig!3 BD19AC1C 2014-11-04 Daniel Ellsberg ellsberg@example.org │ sig! 68FD0088 2014-11-04 Glenn Greenwald glenn@example.org │ sub rsa2048/72A4D018 2014-11-04 │ sig! BD19AC1C 2014-11-04 Daniel Ellsberg ellsberg@example.org └────
The fingerprint may also be given without the spaces in which case there is no need for the quotes. If you want to sign only certain user ids of a key, list those user id verbatim after the fingerprint. To create a non-exportable key signature, use the command `--quick-lsign-key' instead.
Since version 2.1.4 it possible to directly add another user id to an existing key:
┌──── │ $ gpg -k 8CFDE12197965A9A │ pub ed25519/8CFDE12197965A9A 2014-08-19 │ uid [ unknown] EdDSA sample key 1 │ $ gpg --quick-adduid 8CFDE12197965A9A 'Sample 2 me@example.org' │ $ gpg -k 8CFDE12197965A9A │ pub ed25519/8CFDE12197965A9A 2014-08-19 │ uid [ unknown] Sample 2 me@example.org │ uid [ unknown] EdDSA sample key 1 └────
Since version 2.1.13 another subkey can directly be added to an existing key:
┌──── │ $ gpg --quick-addkey 15CB723E2000A1A82505F3B7CC00B501BD19AC1C - - 2016-12-31 │ $ gpg -k 15CB723E2000A1A82505F3B7CC00B501BD19AC1C │ pub rsa2048 2014-11-04 [SC] │ 15CB723E2000A1A82505F3B7CC00B501BD19AC1C │ uid [ unknown] Daniel Ellsberg ellsberg@example.org │ sub rsa2048 2014-11-04 [E] │ sub rsa2048 2016-06-06 [E] [expires: 2016-12-31] └────
Here we created another encryption subkey with an expiration date. The key listing also shows the default key listing format introduced with 2.1.13. There are a lot of other options to the `--quick-addkey' command which are described in the manual.
Since version 2.1.14 it possible to revoke a user id on an existing key:
┌──── │ $ gpg -k 8CFDE12197965A9A │ pub ed25519/8CFDE12197965A9A 2014-08-19 │ uid [ unknown] Sample 2 me@example.org │ uid [ unknown] EdDSA sample key 1 │ $ gpg --quick-revuid 8CFDE12197965A9A 'EdDSA sample key 1' │ $ gpg -k 8CFDE12197965A9A │ pub ed25519/8CFDE12197965A9A 2014-08-19 │ uid [ unknown] Sample 2 me@example.org └────
Since version 2.1.17 the expiration date of the primary key can be changed directly:
┌──── │ $ gpg --quick-set-expire 5B83120DB1E3A65AE5A8DCF6AA43F1DCC7FED1B7 2017-12-31 │ $ gpg -K 5B83120DB1E3A65AE5A8DCF6AA43F1DCC7FED1B7 │ sec rsa2048 2016-06-22 [SC] [expires: 2017-12-31] │ 5B83120DB1E3A65AE5A8DCF6AA43F1DCC7FED1B7 │ uid [ultimate] steve.biko@example.net │ ssb rsa2048 2016-06-22 [E] │ │ $ gpg --quick-set-expire 5B83120DB1E3A65AE5A8DCF6AA43F1DCC7FED1B7 none │ $ gpg -K 5B83120DB1E3A65AE5A8DCF6AA43F1DCC7FED1B7 │ sec rsa2048 2016-06-22 [SC] │ 5B83120DB1E3A65AE5A8DCF6AA43F1DCC7FED1B7 │ uid [ultimate] steve.biko@example.net │ ssb rsa2048 2016-06-22 [E] └────
1.6 Improved Pinentry support ─────────────────────────────
When using a recent Pinentry module (0.90, GTK+ variant), the gpg-agent will not anymore show two separate Pinentry dialogs to enter a new passphrase and later to confirm the new passphrase. Instead the first dialog also has the confirm/repeat entry and internally checks whether they match.
With any Pinentry version the several separate dialogs to inform and ask for confirmation about questionable properties of a new passphrase (e.g. length, only alpha letters) have been combined into one dialog to show all non-asserted constraints at once.
The GTK+ Pinentry does now allow pasting of values into the entries.
Copying them from the entries is still inhibited on purpose.
Depending on the system, the option no-grab' may be required for in the gpg-agent.conf' file to actually make use of the paste feature.
1.7 Auto-start of the gpg-agent ───────────────────────────────
The /gpg-agent/ is the central part of the GnuPG system. It takes care of all private (secret) keys and if required diverts operations to a smartcard or other token. It also provides support for the Secure Shell by implementing the ssh-agent protocol.
The classic way to run /gpg-agent/ on Unix systems is by launching it
at login time and use an environment variable (GPG_AGENT_INFO') to tell the other GnuPG modules how to connect to the agent. However, correctly managing the start up and this environment variable is cumbersome so that an easier method is required. Since GnuPG 2.0.16 the --use-standard-socket' option already allowed to start the agent
on the fly; however the environment variable was still required.
With GnuPG 2.1 the need of GPG_AGENT_INFO' has been completely removed and the variable is ignored. Instead a fixed Unix domain socket named S.gpg-agent' in the GnuPG home directory (by default
`~/.gnupg') is used. The agent is also started on demand by all tools
requiring services from the agent.
If the option --enable-ssh-support' is used the auto-start mechanism does not work because /ssh/ does not know about this mechanism. Instead it is required that the environment variable SSH_AUTH_SOCK'
is set to the S.gpg-agent.ssh' socket in the GnuPG home directory. Further /gpg-agent/ must be started: Either by using a GnuPG command which implicitly starts /gpg-agent/ or by using gpgconf --launch
gpg-agent' to explicitly start it if not yet done.
1.8 Duplicate long key id fixes ───────────────────────────────
A deficit of the OpenPGP protocol is that signatures carry only a limited indication on which public key has been used to create a signature. Thus a verification engine may only use this “long key id” to look up the key in its own store or from a public keyserver. Unfortunately it has now become possible to create a key with a long key id matching the key id of another key. Importing a key with a long key id already used by another key in gpg’s local key store was not possible due to checks done on import. Now, if the “wrong” key has been imported first /gpg/ would not allow later import of the second “correct” key. This problem has been fixed in 2.1 by allowing the import and by doing trial verification against all matching keys.
1.9 Enhanced Dirmngr ────────────────────
Before version 2.1, /gpg/ used so-called keyserver helpers to access the OpenPGP keyservers. A problem with that is that they are short living processes which are not able to keep a state. With 2.1, the formerly separate package Dirmngr (which was separate due to copyright assignment reasons) has been integrated into GnuPG.
In the past /dirmngr/ was only used by /gpgsm/ for X.509 (S/MIME) CRL and OCSP handling. Being a proper part of GnuPG /dirmngr/ does now also care about accessing OpenPGP keyservers. This make its easier to debug problems with the keyservers and to exchange additional information about the keyserver between /gpg/ and /dirmngr/. It will eventually also be possible to run background tasks to refresh keys.
Although the ability to start /dirmngr/ as a system service is still available, this is not anymore recommended and instead /dirmngr/ is now by default started on-demand, very similar to /gpg-agent/.
1.10 Better keyserver pool support ──────────────────────────────────
For load balancing reasons, keyservers are organized in pools to enable instant round-robin DNS assignment of random keyservers. A problem with that approach is that the DNS resolver is not aware of the state of the keyserver. If a keyserver has gone down or a routing problems occurs, /gpg/ and its keyserver helpers were not aware of it and would try over and over to use the same, dead, keyserver up until the DNS information expires and a the DNS resolver assigned a new server from the pool.
The new /dirmngr/ in GnuPG does not use the implicit round-robin of the DNS resolver but uses its own DNS lookup and keeps an internal table of all hosts from the pool along with the encountered aliveness state. Thus after a failure (timeout) of a request, /dirmngr/ flags a host as dead and randomly selects another one from the pool. After a few hours the flag is removed so that the host will be tried again. It is also possible to mark a specific host from a pool explicitly as dead so that it won’t be used in the future. To interact with the /dirmngr/ the `gpg-connect-agent' tool is used:
┌──── │ $ gpg-connect-agent --dirmngr 'help keyserver' /bye │ $ gpg-connect-agent --dirmngr 'keyserver --hosttable' /bye └────
The first command prints a help screen for the keyserver command and the second command prints the current host table.
1.11 Faster keyring format ──────────────────────────
The format GnuPG has always used for the public keyring is actually a slightly extended version of the on-the-wire format for OpenPGP key exchange. This format is quite inflexible to work with when random access to keys in the keyring is required. In fact /gpg/ always parsed all keys in the keyring until it encountered the desired one. With a large keyring (more than a few thousand keys) this could be quite slow.
From its very beginning /gpgsm/ has used a different format to store public keys (certificates) which we call a /keybox/. That file format carries meta information about the stored keys and thus allows searching without actually parsing the key and computing fingerprints and such. The /keybox/ format has been designed to be protocol independent and with 2.1 support for OpenPGP keys has been added. Random access to the keys is now really fast and keyrings with 30000 keys and more are now easily possible. That change also enables us to easily introduce other storage methods
If no pubring.gpg' is found, /gpg/ defaults to the new /keybox/ format and creates a pubring.kbx' keybox file. If such a keybox file
already exists, for example due to the use of /gpgsm/, it will also be
used for OpenPGP keys. However, if a pubring.gpg' is found and no keybox file with OpenPGP keys exists, the old pubring.gpg' will be
used. Take care: GnuPG versions before 2.1 will always use the
`pubring.gpg' file and not know anything about keys stored in the
keybox file.
To convert an existing pubring.gpg' file to the keybox format, you first backup the ownertrust values, then rename the file to (for example) publickeys', so it won’t be recognized by any GnuPG version,
then run import, and finally restore the ownertrust values:
┌──── │ $ cd ~/.gnupg │ $ gpg --export-ownertrust >otrust.lst │ $ mv pubring.gpg publickeys │ $ gpg --import-options import-local-sigs --import publickeys │ $ gpg --import-ownertrust otrust.lst └────
You may then rename the publickeys' file back so that it can be used by older GnuPG versions. Remember that in this case you have two independent copies of the public keys. The ownertrust values are kept by all gpg versions in the file trustdb.gpg' but the above
precautions need to be taken to keep them over an import.
1.12 Auto-generated revocation certificates ───────────────────────────────────────────
This version creates an ASCII armored revocation certificate for each generated keypair and stores that certificate in a file named after the fingerprint of the key in the `openpgp-revocs.d' directory below the GnuPG home directory. Brief instructions on how to use this revocation certificate are put at the top of the file.
1.13 Improved card support ──────────────────────────
The /scdaemon/, which is responsible for accessing smardcards and other tokens, has received many updates. In particular pluggable USB readers with a fixed card now work smoothless and similar to standard readers. The latest features of the [gnuk] token are supported. Code for the SmartCard-HSM has been added. More card readers with a PIN pad are supported. The internal CCID driver does now also work with certain non-auto-configuration equipped readers.
Since version 2.1.19 multiple card readers are support and the format of the Pinentry prompts has been changed to show more information on the requested card.
[gnuk] http://www.fsij.org/doc-gnuk/
1.14 New format for key listings ────────────────────────────────
Due to the introduction of ECC keys the old format to list keys was not anymore suitable. In particular, the length of an ECC key is defined but its expressiveness is limited without the other parameters of the curve. The common way to describe an ECC key is by using the assigned name of its curve. To allow for a common description we now either use the algorithm name with appended key length or use the name of the curve:
┌──── │ pub 2048D/1E42B367 2007-12-31 [expires: 2018-12-31] │ │ pub dsa2048 2007-12-31 [SC] [expires: 2018-12-31] │ 80615870F5BAD690333686D0F2AD85AC1E42B367 │ │ pub ed25519 2014-10-18 [SC] │ 0B7F0C1D690BC440D5AFF9B56902F00A0AA914C9 └────
The first two "pub"-items show the same key in the old format and in
the new format. The third "pub"-item shows an example of an ECC key
using an ed25519 curve. Note that since version 2.1.13 the key id is
not anymore shown. Instead the full fingerprint is shown in a compact
format; by using the option --with-fingerprint' the non-compact format is used. The --keyid-format' option can be used to switch
back to the discouraged format which prints only the key id.
As a further change the validity of a key is now shown by default;
that is show-uid-validity' is implicitly used for the --list-options'.
The annotated key listing produced by the --with-colons' options did not change. However a couple of new fields have been added, for example if the new option --with-secret' is used the “S/N of a token
field” indicates the presence of a secret key even in a public key
listing. This option is supported by recent [GPGME] versions and
makes writing of key manager software easier.
[GPGME] https://gnupg.org/software/gpgme/
1.15 Recipient key from file ────────────────────────────
Since version 2.1.14 it is possible to specify the recipient’s key by
providing a file with that key. This done with the new options
--recipient-file' (or short -f') and --hidden-recipient-file' (or short -F'). The file must containing exactly one key in binary or
armored format. All keys specified with those options are always
considered fully valid. These option may be mixed with the regular
options to specify a key. Along with the new convenience option
`--no-keyring' it is now possible to encrypt data without maintaining
a local keyring.
1.16 Using gpg as a filter ──────────────────────────
Since version 2.1.14 the export and import options have been enhanced to allow the use of /gpg/ to modify a key without first storing it in the keyring. For example:
┌────
│ $ gpg --import-options import-minimal,import-export
│ --output smallkey.gpg --import key.gpg
└────
copies the keys in keys.gpg' to smallkey.gpg' while also removing
all key signatures except for the latest self-signatures. This can
even be further restricted to copy only a specific user ID to the
output file:
┌────
│ $ gpg --import-options import-minimal,import-export
│ --import-filter keepuid='mbox = foo@example.org'
│ --output smallkey.gpg --import key.gpg
└────
Here the new `--import-filter' option is used to remove all user IDs except for those which have the mail address “foo@example.org”. The same is also possible while exporting a key:
┌────
│ $ gpg --export-filter keepuid='mbox = me@example.org'
│ --armor --export 8CFDE12197965A9A >smallkey.asc
└────
1.17 Support for Putty ──────────────────────
On Windows the new option --enable-putty-support' allows gpg-agent to act as a replacement for [Putty]’s authentication agent /Pageant/. It is the Windows counterpart for the --enable-ssh-support' option as
used on Unix.
[Putty] http://www.chiark.greenend.org.uk/~sgtatham/putty/
1.18 Export of SSH public keys ──────────────────────────────
The new command --export-ssh-key' makes it easy to export an /ssh/ public key in the format used for ssh’s authorized_keys' file. By
default the command exports the newest subkey with an authorization
usage flags. A special syntax can be used to export other subkeys.
This command is available since 2.1.11 and replaces the former debug
utility /gpgkey2ssh/.
1.19 Improved X.509 certificate creation ────────────────────────────────────────
In addition to an improved certificate signing request menu, it is now possible to create a self-signed certificate using the interactive menu of /gpgsm/.
In batch mode the certificate creation dialog can now be controlled by a parameter file with several new keywords. Such a parameter file allows the creation of arbitrary X.509 certificates similar to what can be done with /openssl/. It may thus be used as the base for a CA software. For details see the “CSR and certificate creation” section in the manual.
The new commands `--export-secret-key-p8' and –export-secret-key-raw= may be used to export a secret key directly in PKCS#8 or PKCS#1 format. Thus X.509 certificates for TLS use may be managed by /gpgsm/ and directly exported in a format suitable for OpenSSL based servers.
1.20 Scripts to create a Windows installer ──────────────────────────────────────────
GnuPG now comes with the /speedo/ build system which may be used to quickly download and build GnuPG and all its direct dependencies on a decent Unix system. See the README file for more instructions.
The very same script may also be used to build a complete NSIS based installer for Windows using the mingw-w64 cross-compiler toolchain. That installer will feature GnuPG proper, GPA as graphical frontend, and GpgEX as a Windows Explorer extension. GnuPG needs to be unpacked and from the top source directory you run this command
┌──── │ make -f build-aux/speedo.mk w32-installer └────
This command downloads all direct dependencies, checks the signatures using the GnuPG version from the build system (all Linux distros feature a suitable GnuPG tool), builds everything from source, and uses NSIS to create the installer. Although this sounds easy, some experience in setting up a development machine is still required. Some versions of the toolchain exhibit bugs and thus your mileage may vary. See the [Wiki] for more info.
Support for keyserver access over TLS is currently not available but will be added with one of the next point releases.