.. Copyright 2018 Cedric Mesnil , Ledger SAS Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. .. ------------------------------------------------------------------------ LaTex substitution Definition ------------------------------------------------------------------------ License ======= Author: Cedric Mesnil License: | Copyright 2017 Cedric Mesnil , Ledger SAS | | Licensed under the Apache License, Version 2.0 (the "License"); | you may not use this file except in compliance with the License. | You may obtain a copy of the License at | | http://www.apache.org/licenses/LICENSE-2.0 | | Unless required by applicable law or agreed to in writing, software | distributed under the License is distributed on an "AS IS" BASIS, | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | See the License for the specific language governing permissions and | limitations under the License. Introduction ============ GnuPG application for Ledger Blue and Nano S This application implements "The OpenPGP card" specification revision 3.0. This specification is available in doc directory and at https://g10code.com/p-card.html . The application supports: - RSA with key up to 4096 bits - ECDSA with secp256k1, secp256r1, brainpool 256r1 and brainpool 256t1 curves - EDDSA with Ed25519 curve - ECDH with secp256k1, secp256r1, brainpool 256r1, brainpool 256t1 and curve25519 curves This release has known missing parts (see also [GPGADD]) : - Ledger Blue support - Seed mode ON/OFF via apdu How to install GPG Application ============================== Nano S / Blue ------------- For both, source and binary installation, use the most recent tag. From Binary ~~~~~~~~~~~~~ Use the "Ledger Manager" Chrome App. See https://www.ledgerwallet.com/apps/manager for details. As the "OpenPGP card" application is not fully compliant with UI and documentation guidelines, the application is in developer section: click on "Show delevopers items" on the bottom right corner to see it. - Launch the Ledger Manager. See `Ledger Manager `_ and ` `_ for details about installing and using the manager; - Connect your Nano S or your Blue, enter your PIN, and stay on the dashboard; - Click on *show developer items* on the bottom right corner; - Click on the green bottom arrow icon near the Ledger *Open PGP* logo; - Confirm the installation when required on your device by pressing the right button above the checkmark; - Quit the Ledger Manager The application is ready to use! From source ~~~~~~~~~~~~~ Building from sources requires the the Nano S SDK 1.4.2.1 on firmware 1.4.2. See https://github.com/LedgerHQ/nanos-secure-sdk Refer to the SDK documentation for the compiling/loading... System Configuration -------------------- For Linux and MAC, until version 1.4.27, Ledger CCID interface is not supported by default by pcscd and must be manually added For windows.... Linux ~~~~~ You have to have to add the NanoS to /etc/libccid_Info.plist - In ifdVendorID add the entry 0x2C97 - In ifdProductID add the entry 0x0001 - In ifdFriendlyName add the entry Ledger Token These 3 entries must be added at the end of each list. MAC ~~~ 1. First it is necessary to [disable SIP](https://developer.apple.com/library/mac/documentation/Security/Conceptual/System_Integrity_Protection_Guide/ConfiguringSystemIntegrityProtection/ConfiguringSystemIntegrityProtection.html) That doesn't allow the editing of files in /usr/. 2. You have to add the Nano S to /usr/libexec/SmartCardServices/drivers/ifd-ccid.bundle/Contents/Info.plist - In ifdVendorID add the entry 0x2C97 - In ifdProductID add the entry 0x0001 - In ifdFriendlyName add the entry Ledger Token This 3 entries must be added at the end of each list. 3. [Enable SIP](https://developer.apple.com/library/content/documentation/Security/Conceptual/System_Integrity_Protection_Guide/ConfiguringSystemIntegrityProtection/ConfiguringSystemIntegrityProtection.html) Windows ~~~~~~~ TODO Nano S OpenPGP Card application explained ========================================= Menu Overview ------------- The full menu layout is : | \ *Device Info* | Select Slot | \ *Choose:* | Slot 1 #+ | Slot 2 | Slot 3 | Set Default | Settings | Key Template | Choose Key... | Signature | Decryption | Authentication | Choose Type... | RSA 2048 | RSA 3072 | RSA 4096 | NIST P256 | Brainpool 256R1 | ED25519 | Set Template | Seed mode | \ ** | Set on | Set off | PIN mode | UIF mode | \ *Choose:* | Host | On Screen | Confirm only #+ | Trust | Reset | About | \ *OpenPGP Card* | \ *(c) Ledger SAS* | \ *Spec 3.0* | \ *App 1.0.1* | Emphasis entries are not selectable and just provide information. | A "**#**" after the entry label means default value on reset. | A "**+**" after the entry label means current value. Device Info ------------- The *Device Info* provides current user and slot information. The format is: | with: * **name** is the one provided to ``gpg --card-edit``. See [GPGSC]. * **n** is the current slot, see below. * **s** is the 32 bits card serial number. Note that the last three bits always encode the current slot value. Select Slot ------------- A Slot is a set of three key pairs *Signature, Decryption, Authentication* as defined by gnupg specification. Usually a GPG card application only manages a single set. Ledger version enhances this and allows you to manage three key sets. The *Select Slot* menu allows you to select the slot you want to play with, and to set the default slot when the application start. To change the current slot, display the slot you want and select it To change the default slot, first select it, and then select the *Set Default* entry. Settings -------- Key Template ~~~~~~~~~~~~ A key template is defined by the OpenGPG card application specification. It describes the key to be generated with the ``generate`` command in ``gpg --card-edit`` The problem is there is no way with the ``gpg --card-edit`` command line to easily set up the desired template, except for Ed25519. To set up a new ECC template you have tow choice: the NanoS menu or the gpg-connect-agent tools. **gpg-connect-agent** (recommended) This method suppose you have correctly configured your GnuPG tool. See the dedicated section for that. In a terminal launch : gpg-connect-agent "SCD SETATTR KEY-ATTR --force 1 " /bye gpg-connect-agent "SCD SETATTR KEY-ATTR --force 2 18 " /bye gpg-connect-agent "SCD SETATTR KEY-ATTR --force 3 " /bye This 3 commands fix, in that order, the template for Signature, Decryption, Authentication keys. Supported curve name are: - secp256k1 with tag 19 - nistp256 with tag 19 - brainpoolP256r1 with tag 19 - cv25519 (only for key 2) - ed25519 with tag 22 (only for key 1 and 3) To show the current template use the ``gpg --card-status`` command. **NanoS menu** First under *Choose Key* menu, select the one of three keys for which you want to modify the template. Then under "Choose Type", select the desired key template. Finally select "Set Template" entry to set it. To show the current template use the ``gpg --card-status`` command. Seed mode ~~~~~~~~~ **WARNING** : SEED MODE IS EXPERIMENTAL When generating new keys on NanoS, those keys can be generated randomly or in a deterministic way. The deterministic way is specified in [GPGADD]. The current mode is displayed in the first sub menu. To activate the seeded mode select *ON*, to deactivate the seeded mode select *OFF*. When the application starts, the seeded mode is always set to *OFF* **WARNING** : SEED MODE IS EXPERIMENTAL PIN mode ~~~~~~~~ Some operations require the user to enter his PIN code. The default PIN values are: - user: ``123456`` - admin: ``12345678`` The PIN entry can be done using four methods, named "*Host*", "*On Screen*", "*Confirm only*", "*Trust*". After each mode a *+* or *#* symbol may appear to tell which mode is the current one and which one is the default when the application starts. The default mode can be changed by first selecting the desired mode and then selecting the *Set default" menu. Note that *Trust* can not be set as default mode. Note that *On Screen*", "*Confirm only*" and "*Trust*" may not work if the client application does not support it. In that case the "*Host*" should be automatically used by the client in a transparent way. **Host** The PIN is entered on the external computer. **On Screen** The PIN is entered on the Nano S or Blue screen. For entering the PIN choose the next digit by using the left or right button. When the digit you expect is displayed select it by pressing both buttons ar the same time .. image:: pin_entry.png :align: middle Once all digits are selected, validate the PIN by selecting the **'V'** (Validate) letter .. image:: pin_validate.png :align: middle If you want to change the previous digit select the **'C'** (Cancel) letter. .. image:: pin_cancel.png :align: middle Finnaly if you want to abort the PIN entry, select the **'A'** (Abort) letter. .. image:: pin_abort.png :align: middle **Confirm only** The user is requested, on the NanoS or Blue screen, to confirm the PIN validation. The PIN value is not required, the user just has to push the *REJECT* or *OK* button on the device. This is the default mode after application installation. .. image:: pin_confirm.png :align: middle **Trust** Act as if the PIN is always validated. This is a dangerous mode which should only be used in a highly secure environment. UIF mode ~~~~~~~~ By activating UIF mode for either signature, decryption or authentication, a user validation will be ask by the device each time the related operation is performed. To activate or deactivate the UIF, select the operation to protect and press both button. When activated, a '+' symbol appears after the operation name. Reset ~~~~~ Selecting the menu will erase all OpenPGP Card Application data and will reset the application in its '*just installed*' state. Nano S OpenPGP Card application usage ===================================== GPG --- The OpenGPG Card application need at least version 2.1.19 for full support. A version prior to 2.1.19 will fail when using ECC. You should test with a test key and make a backup of your keyring before starting, except if your are sure about what you do. Configuration ~~~~~~~~~~~~~ In order to use a Ledger device with gpg it is needed to explicitly setup the reader and the delegated PIN support. Edit the file ~/.gnupg/scdaemon.conf and add the following lines: | ``reader-port "Ledger Token [Nano S] (0001) 01 00"`` | ``allow-admin`` | ``enable-pinpad-varlen`` If you do not set the ``enable-pinpad-varlen`` option, even if Nano S is configured in *On Screen* mode, gpg will keep requesting the PIN on the host. You can check ``the reader-port`` value by running the command line ``pcsc_scan``: | ``$ pcsc_scan `` | ``PC/SC device scanner`` | ``V 1.4.27 (c) 2001-2011, Ludovic Rousseau `` | ``Compiled with PC/SC lite version: 1.8.14`` | ``Using reader plug'n play mechanism`` | ``Scanning present readers...`` | ``0: Alcor Micro AU9560 00 00`` | ``1: Ledger Token [Nano S] (0001) 01 00`` | ``Reader 0: Alcor Micro AU9560 00 00`` | ``Card state: Card removed, `` | ``Reader 1: Ledger Token [Nano S] (0001) 01 00`` | ``Card state: Card inserted, `` | ``ATR: 3B 00`` | ``+ TS = 3B --> Direct Convention`` | ``+ T0 = 00, Y(1): 0000, K: 0 (historical bytes)`` Get/Set basic information ~~~~~~~~~~~~~~~~~~~~~~~~~ The ``gpg --card-status`` command provides default card information. Just after installation it should look like this: | ``$ gpg --card-status`` | ``Reader ...........: Ledger Token [Nano S] (0001) 01 00`` | ``Application ID ...: D2760001240103002C97AFB114290000`` | ``Version ..........: 3.0`` | ``Manufacturer .....: unknown`` | ``Serial number ....: AFB11429`` | ``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 .: 12 12 12`` | ``PIN retry counter : 3 0 3`` | ``Signature counter : 0`` | ``Signature key ....: [none]`` | ``Encryption key....: [none]`` | ``Authentication key: [none]`` | ``General key info..: [none]`` You can set the user information with the ``gpg --card-edit`` command and ``name``, ``url``, ``login``, ``lang``, ``sex`` subcommands. For example if you want to set up your name: | ``$ gpg --card-edit`` | ``gpg/card> admin`` | ``Admin commands are allowed`` | ```` | ``gpg/card> name`` | ``Cardholder's surname: Mesnil`` | ``Cardholder's given name: Cedric`` | ```` | ``gpg/card> sex`` | ``Sex ((M)ale, (F)emale or space): M`` | ```` | ``gpg/card> list`` | ```` | ``Reader ...........: Ledger Token [Nano S] (0001) 01 00`` | ``Application ID ...: D2760001240103002C97AFB114290000`` | ``Version ..........: 3.0`` | ``Manufacturer .....: unknown`` | ``Serial number ....: AFB11429`` | ``Name of cardholder: Cedric Mesnil`` | ``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 .: 12 12 12`` | ``PIN retry counter : 3 0 3`` | ``Signature counter : 0`` | ``Signature key ....: [none]`` | ``Encryption key....: [none]`` | ``Authentication key: [none]`` | ``General key info..: [none]`` Notes: * Modifying the user information will prompt you to enter ``User PIN``. * Setting user information is not required for using gpg client. Generate new key pair ~~~~~~~~~~~~~~~~~~~~~ For generating a new key pair follow those steps: - Select the desired NanoS OpenPGP Card application slot - Setup the desired key template for this slot - Generate the new key set **Step 1** Starting from main menu: - Select *Select slot* menu - Scroll to desired slot - Select it - Optionally set it as default by selecting *Set Default* menu - Select *Back* to return to main menu. **Step 2** The default template for each three keys (*signature*, *decryption*, *authentication*) is ``RSA 2048``. If you want another kind of key you have to set the template before generating keys. !WARNING!: changing the current template of a key automatically erases the associated key. Starting from main menu: - Select *Settings* menu - Select *Key template* menu - Select *Choose Key...* menu (a) - Scroll and select which key you want to set the new template for - Select *Choose type...* menu - Scroll and select among the supported key types and sizes - Select *Set template* - Repeat this process from (a) if you want to modify another key template - Select *Back* to return to main menu. **Step 3** Once the template has been set, it's possible to generate new key pairs with ``gpg``. !WARNING!: gpg will generate the three key pairs and will overwrite any key already present in the selected slot. Here after is a detailed log of key generation of ECC keys, assuming the three key templates are ``NIST P256``. **Edit Card** | ``$ gpg2 --edit-card`` | ``Reader ...........: Ledger Token [Nano S] (0001) 01 00`` | ``Application ID ...: D2760001240103002C97AFB1142B0000`` | ``Version ..........: 3.0`` | ``Manufacturer .....: unknown`` | ``Serial number ....: AFB1142B`` | ``Name of cardholder: Cedric Mesnil`` | ``Language prefs ...: [not set]`` | ``Sex ..............: male`` | ``URL of public key : [not set]`` | ``Login data .......: [not set]`` | ``Signature PIN ....: not forced`` | ``Key attributes ...: nistp256 nistp256 nistp256`` | ``Max. PIN lengths .: 12 12 12`` | ``PIN retry counter : 3 0 3`` | ``Signature counter : 0`` | ``Signature key ....: [none]`` | ``Encryption key....: [none]`` | ``Authentication key: [none]`` | ``General key info..: [none]`` **Switch to admin mode:** | ``gpg/card>`` *admin* | ``Admin commands are allowed`` **Request new key generation without backup** | ``gpg/card>`` *generate* | ``Make off-card backup of encryption key? (Y/n)`` **n** **Unlock user level ``81``** | ``Please unlock the card`` | ```` | ``Number: 2C97 AFB1142B`` | ``Holder: Cedric Mesnil`` | ```` | ``Use the reader's pinpad for input.`` | `` OK`` | ``Press any key to continue. `` **Set key validity** | ``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)`` *0* | ``Key does not expire at all`` | ``Is this correct? (y/N)``*y* **Set user ID** | ``GnuPG needs to construct a user ID to identify your key.`` | ```` | ``Real name: Cedric Mesnil`` | ``Email address: cedric@ledger.fr`` | ``Comment: `` | ``You selected this USER-ID:`` | `` "Cedric Mesnil "`` | ```` | ``Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit?`` *O* | ```` | ``You selected this USER-ID:`` | `` "Cedric Mesnil "`` **Unlock admin level ``83``** | ``Please enter the Admin PIN `` | ```` | ``Number: 2C97 AFB1142B`` | ``Holder: Cedric Mesnil`` | ```` | ``Use the reader's pinpad for input.`` | `` OK`` | ``Press any key to continue.`` **Unlock user level ``82``** | ``Please unlock the card`` | ```` | ``Number: 2C97 AFB1142B`` | ``Holder: Cedric Mesnil`` | ``Counter: 8`` | ```` | ``Use the reader's pinpad for input.`` | `` OK`` | ``Press any key to continue.`` **Final confirmation** | ``Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit?`` *O* | ``gpg: key DF3FA4A33EF00E47 marked as ultimately trusted`` | ``gpg: revocation certificate stored as '/home/gnuk/.gnupg/openpgp-revocs.d/89F772243C9A3E583CB59AB5DF3FA4A33EF00E47.rev'`` | ``public and secret key created and signed.`` **Get information after key generation** | ``gpg/card> list`` | ```` | ``Reader ...........: Ledger Token [Nano S] (0001) 01 00`` | ``Application ID ...: D2760001240103002C97AFB1142B0000`` | ``Version ..........: 3.0`` | ``Manufacturer .....: unknown`` | ``Serial number ....: AFB1142B`` | ``Name of cardholder: Cedric Mesnil`` | ``Language prefs ...: [not set]`` | ``Sex ..............: male`` | ``URL of public key : [not set]`` | ``Login data .......: [not set]`` | ``Signature PIN ....: not forced`` | ``Key attributes ...: nistp256 nistp256 nistp256`` | ``Max. PIN lengths .: 12 12 12`` | ``PIN retry counter : 3 0 3`` | ``Signature counter : 12`` | ``Signature key ....: F844 38BB CA87 F9A7 6830 F002 F8A4 A353 3CBF CAA5`` | `` created ....: 2017-08-22 15:59:36`` | ``Encryption key....: B1D3 C9F2 C3C5 87CA 36A7 F02E E137 28E9 13B8 77E1`` | `` created ....: 2017-08-22 15:59:36`` | ``Authentication key: F87D EF02 9C38 C43D 41F0 6872 2345 A677 CE9D 8223`` | `` created ....: 2017-08-22 15:59:36`` | ``General key info..: pub nistp256/F8A4A3533CBFCAA5 2017-08-22 cedric mesnilCedric Mesnil `` | ``sec> nistp256/F8A4A3533CBFCAA5 created: 2017-08-22 expires: never `` | `` card-no: 2C97 AFB1142B`` | ``ssb> nistp256/2345A677CE9D8223 created: 2017-08-22 expires: never `` | `` card-no: 2C97 AFB1142B`` | ``ssb> nistp256/E13728E913B877E1 created: 2017-08-22 expires: never `` | `` card-no: 2C97 AFB1142B`` **Say goodbye | ``gpg/card> quit``** At this point it's possible to check that the key has been generated on card with the following command: | ``$ gpg2 --list-secret-keys cedric@ledger`` | ``gpg: checking the trustdb`` | ```` | ``sec> nistp256 2017-08-22 [SC]`` | `` F84438BBCA87F9A76830F002F8A4A3533CBFCAA5`` | `` Card serial no. = 2C97 AFB1142B`` | ``uid [ultimate] cedric mesnilCedric Mesnil `` | ``ssb> nistp256 2017-08-22 [A]`` | ``ssb> nistp256 2017-08-22 [E]`` Moving existing key pair ~~~~~~~~~~~~~~~~~~~~~~~~ This section shows how to move an existing key onto the Ledger device. The key to transfer here is a RSA 4096 bits key: | ``$ gpg2 --list-secret-keys "RSA 4096"`` | ``sec rsa4096 2017-04-26 [SC]`` | `` FB6C6C75FB016635872ED3E49B93CB47F954FB53`` | ``uid [ultimate] RSA 4096`` | ``ssb rsa4096 2017-04-26 [E]`` In case of transfer it is not necessary to previously set the template. It will be automatically changed. When generating a new key, the three keys (*signature*, *decryption*, *authentication*)) are automatically generated. When transferring existing ones, it is possible to choose which one will be moved. **Edit Key** | ``$ gpg2 --edit-key "RSA 4096"`` | ``gpg (GnuPG) 2.1.19; Copyright (C) 2017 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.`` | ```` | ``Secret key is available.`` | ```` | ``sec rsa4096/9B93CB47F954FB53`` | `` created: 2017-04-26 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb rsa4096/49EE12B0F5CBDF26`` | `` created: 2017-04-26 expires: never usage: E `` | ``[ultimate] (1). RSA 4096`` **Select the key to move, here the *encryption* one.** | ``gpg> `` *key 1* | `` `` | ``sec rsa4096/9B93CB47F954FB53`` | `` created: 2017-04-26 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb* rsa4096/49EE12B0F5CBDF26`` | `` created: 2017-04-26 expires: never usage: E `` | ``[ultimate] (1). RSA 4096`` **Move** | ``gpg> `` **keytocard** | ``Please select where to store the key:`` | `` (2) Encryption key`` | ``Your selection?`` *2* **Unlock admin level ``83``** | ``Please enter the Admin PIN`` | ```` | ``Number: 2C97 1D49B409`` | ``Holder: `` | ```` | ``Use the reader's pinpad for input.`` | `` OK`` | ``Press any key to continue.`` **Unlock admin level ``83`` (maybe twice....)** | ``Please enter the Admin PIN`` | ```` | ``Number: 2C97 1D49B409`` | ``Holder: `` | ```` | ``Use the reader's pinpad for input.`` | `` OK`` | ``Press any key to continue.`` | ``sec rsa4096/9B93CB47F954FB53`` | `` created: 2017-04-26 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb* rsa4096/49EE12B0F5CBDF26`` | `` created: 2017-04-26 expires: never usage: E `` | ``[ultimate] (1). RSA 4096`` **Say goobye with saving!** | ``gpg> `` *save* **check** | ``$ gpg2 --edit-keys cedric`` | ``gpg: error reading key: No public key`` | ``gnuk@Lulu:~$ /opt/gnupg2.1.19/bin/gpg2 --edit-key "RSA 4096"`` | ``gpg (GnuPG) 2.1.19; Copyright (C) 2017 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.`` | ```` | ``Secret key is available.`` | ```` | ``sec rsa4096/9B93CB47F954FB53`` | `` created: 2017-04-26 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb rsa4096/49EE12B0F5CBDF26`` | `` created: 2017-04-26 expires: never usage: E `` | `` card-no: 2C97 7BB895B9`` | ``[ultimate] (1). RSA 4096`` | ```` | ``gpg> `` *quit* The encryption key is now associated with a card. Decrypting and Signing ~~~~~~~~~~~~~~~~~~~~~~ Decrypting and Signing will act exactly the same way as if keys were not on the card. The only difference is ``gpg`` will request the PIN code instead of the passphrase. SSH --- Overview ~~~~~~~~ In order to use gpg for SSH authentication, an "authentication" is needed. There are two solutions for that, either generate one on the device or add an authentication sub-key to your existing master gpg key. Once done, it is necessary to configure ssh to point to the right key and delegate the authentication to *gpg-ssg-agent* instead of *ssh-agent*. Generate new key on device ~~~~~~~~~~~~~~~~~~~~~~~~~~ The important thing to keep in mind here is there is no way to tell gpg to only generate the authentication key. So generating this key will also generate the two other under a new identity and will erase existing keys on the current slot on the device. Nevertheless, if you want to use a different identity for ssh login, you can use another slot on the device. See `Nano S OpenPGP Card application explained`_ and `Generate new key pair`_. Add sub-key ~~~~~~~~~~~ **Edit pgp key set** | ``$ gpg --expert --edit-key cedric`` | ``gpg (GnuPG) 2.1.15; Copyright (C) 2016 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.`` | ``Secret key is available.`` | ``sec rsa2048/831415DA94A9A15C`` | `` created: 2017-08-25 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb rsa2048/8E95F2999EEC38C4`` | `` created: 2017-08-25 expires: never usage: E `` | ``[ultimate] (1). cedric`` **Add sub key** | ``gpg> *addkey*`` | ``Please select what kind of key you want:`` | `` (3) DSA (sign only)`` | `` (4) RSA (sign only)`` | `` (5) Elgamal (encrypt only)`` | `` (6) RSA (encrypt only)`` | `` (7) DSA (set your own capabilities)`` | `` (8) RSA (set your own capabilities)`` | `` (10) ECC (sign only)`` | `` (11) ECC (set your own capabilities)`` | `` (12) ECC (encrypt only)`` | `` (13) Existing key`` | ``Your selection? 8`` **Toggle sign/encrypt OFF, Toggle authentication ON** | ``Possible actions for a RSA key: Sign Encrypt Authenticate `` | ``Current allowed actions: Sign Encrypt `` | `` (S) Toggle the sign capability`` | `` (E) Toggle the encrypt capability`` | `` (A) Toggle the authenticate capability`` | `` (Q) Finished`` | ``Your selection?`` *S* | ``Possible actions for a RSA key: Sign Encrypt Authenticate `` | ``Current allowed actions: Encrypt `` | `` (S) Toggle the sign capability`` | `` (E) Toggle the encrypt capability`` | `` (A) Toggle the authenticate capability`` | `` (Q) Finished`` | ``Your selection?`` *E* | ``Possible actions for a RSA key: Sign Encrypt Authenticate `` | ``Current allowed actions: `` | `` (S) Toggle the sign capability`` | `` (E) Toggle the encrypt capability`` | `` (A) Toggle the authenticate capability`` | `` (Q) Finished`` | ``Your selection?`` *A* | ``Possible actions for a RSA key: Sign Encrypt Authenticate `` | ``Current allowed actions: Authenticate `` | `` (S) Toggle the sign capability`` | `` (E) Toggle the encrypt capability`` | `` (A) Toggle the authenticate capability`` | `` (Q) Finished`` | ``Your selection? Q`` **Set key options** | ``RSA keys may be between 1024 and 4096 bits long.`` | ``What keysize do you want? (2048)`` *2048* | ``Requested keysize is 2048 bits`` | ``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)`` *0* | ``Key does not expire at all`` | ``Is this correct? (y/N)`` *y* | ``Really create? (y/N)`` *y* | ``We need to generate a lot of random bytes. It is a good idea to perform`` | ``some other action (type on the keyboard, move the mouse, utilize the`` | ``disks) during the prime generation; this gives the random number`` | ``generator a better chance to gain enough entropy.`` | ``sec rsa2048/831415DA94A9A15C`` | `` created: 2017-08-25 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb rsa2048/8E95F2999EEC38C4`` | `` created: 2017-08-25 expires: never usage: E `` | ``ssb rsa2048/C20B90E12F68F035`` | `` created: 2017-08-28 expires: never usage: A `` | ``[ultimate] (1). cedric`` **Select the key and move it** | ``gpg> key`` *2* | ```` | ``sec rsa2048/831415DA94A9A15C`` | `` created: 2017-08-25 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb rsa2048/8E95F2999EEC38C4`` | `` created: 2017-08-25 expires: never usage: E `` | ``ssb* rsa2048/C20B90E12F68F035`` | `` created: 2017-08-28 expires: never usage: A `` | ``[ultimate] (1). cedric`` | ```` | ``gpg>`` *keytocard* | ``Please select where to store the key:`` | `` (3) Authentication key`` | ``Your selection?`` *3* | `` `` | ``sec rsa2048/831415DA94A9A15C`` | `` created: 2017-08-25 expires: never usage: SC `` | `` trust: ultimate validity: ultimate`` | ``ssb rsa2048/8E95F2999EEC38C4`` | `` created: 2017-08-25 expires: never usage: E `` | ``ssb* rsa2048/C20B90E12F68F035`` | `` created: 2017-08-28 expires: never usage: A `` | ``[ultimate] (1). cedric`` **Save and Quit** | ``gpg>`` save | ``$ `` Configure SSH and GPG ~~~~~~~~~~~~~~~~~~~~~ First, tell gpg-agent to enable ssh-auth feature by adding the following line to your .gpg-agent.conf: ``enable-ssh-support`` Starting with gpg2 it necessary to add some configuration options to make the *pinentry* work properly. Add the following line to ~/.bashrc file: | ``export SSH_AUTH_SOCK=`gpgconf --list-dirs agent-ssh-socket` `` | ``export GPG_TTY=`tty` `` | ``gpgconf --launch gpg-agent `` It may be also necessary to setup the loopback pinentry options. Add the following line to your ~/.gnupg/gpg-agent.conf: ``allow-loopback-pinentry`` And add the following line to your ~/.gnupg/gpg.conf: ``pinentry-mode loopback`` Then export your authentication public key. First execute the ``gpg -k --with-subkey-fingerprint --with-keygrip cedric`` command. | ``pub rsa2048 2017-08-25 [SC]`` | `` 7886147C4C2E5CE2A4B1546C831415DA94A9A15C`` | `` Keygrip = DE2B63C13AB92EBD2D05C1021A9DAA2D40ECB564`` | ``uid [ultimate] cedric`` | ``sub rsa2048 2017-08-25 [E]`` | `` 789E56872A0D9A5AC8AF9C2F8E95F2999EEC38C4`` | `` Keygrip = 9D7C2EF8D84E3B31371A09DFD9A4B3EF72AB4ACE`` | ``sub rsa2048 2017-08-28 [A]`` | `` 2D0E4FFFAA448AA2770C7F02C20B90E12F68F035`` | `` Keygrip = 6D60CB58D9D66EE09804E7FE460E865A91F5E41A`` Add the keygrip of the authentication key, the one identified by ``[A]``, to .gnupg/sshcontrol file: | ``$ echo 6D60CB58D9D66EE09804E7FE460E865A91F5E41A > .gnupg/sshcontrol`` Export your authentication key, identifier by its fingerprint, in a SSH compliant format. | ``$ gpg --export-ssh-key 2D0E4FFFAA448AA2770C7F02C20B90E12F68F035`` | ``ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDCIARKh0IZTHld+I6oA8nwrgnCUQE8f`` | ``7X3pmI4ZwryT52fKhpcsQJsd3krodXrM//LiK8+m2ZRMneJ9iGlqqE7SCyZkNBj1GUm9s`` | ``rK3Q5eoR6nU0s+sq17b/FAtQWHBJTqqaOtyA33hFj5twUtWZ6rokX9cNZrD1ne8kRVHDe`` | ``3uEBsaY5PR1Tuko/GwywLyZu0SwfEobl/RPjL7P8rUSc7DTHpQMw8fjJFb4BNvIHAlaVC`` | ``5FwZwkuogygaJdN/44MayHFmOZmzx9CAgYgLpTzen35+CcyhlqCqi+HjNlnHL2DDWd4iR`` | ``d3Y6pY8LjS3xQkECc3Bhedptp17D+H9AVJt openpgp:0x2F68F035`` Finaly copy the above export (``ssh-rsa AAAAB...Jt openpgp:0x2F68F035``) into the ~/.ssh/authorized_keys file on your remote server. Now, if everything is correctly setup and running, an ``ssh-add -l`` should show your key: | ``$ ssh-add -l`` | ``2048 SHA256:sLCzsoi5GAG2kJkG6hSp8gTLPxSvo/zNtsks2kQ7vTU cardno:2C979421A9E1 (RSA)`` | ``2048 SHA256:sLCzsoi5GAG2kJkG6hSp8gTLPxSvo/zNtsks2kQ7vTU (none) (RSA)`` And you should be able to ssh to your remote server with your gpg key! Trouble/FAQ ----------- **Q:** pinentry failed with a strange canceled message: **R:** there is some problem with gpg2 and pinentry-gnome3. You may update your system to use pinentry-gtk-2. Under Ubuntu-like OS, use ``update-alternatives --config pinentry`` | ```` **Q:** gpg-connection agent failed **R:** check that you don't have multiple running agents. After setting-up all SSH stuff, try to fully logout/login | ```` **Q:** It does not work at all, HELP ME!!! **R** Please keep calm and do not cry. Add the following option to ~/.gnupg/gpg-agent.conf | ``debug-level guru`` | ``log-file /tmp/gpgagent.log`` Add the follwing option to ~/.gnupg/scdaemon.conf | ``log-file /tmp/scd.log`` | ``debug-level guru`` | ``debug-all`` Make a nice issue report under github providing log and and command line you run. **!*WARNING*!** : this may reveal confidential information such as key values. Do your log with a test key. Annexes ======= References ---------- * [GPG] *The GNU Privacy Guard*, https://gnupg.org/ * [GPGSC] *The GnuPG Smartcard HOWTO*, https://gnupg.org/howtos/card-howto/en/smartcard-howto.html * [G10CODE] *The OpenPGP card application*, https://g10code.com/p-card.html * [GPGADD] *The OpenPGP card application add-on*, https://github.com/LedgerHQ/blue-app-openpgp-card/blob/master/doc/gpgcard3.0-addon.rst