Quick Start Tutorial
The purpose of this tutorial is to demonstrate basic functionalities of different key types: Authentication Key, Asymmetric Key and Wrap Key. We start with a fresh YubiHSM 2 configuration and we proceed in generating a new Authentication Key. Then we generate an Asymmetric Key for signing purposes. We sign an arbitrary amount of data and verify that our signature is correct. Part of this documentation is to demonstrate how to backup a key on a second YubiHSM 2. We do so by wrapping the Asymmetric Key and re-importing it into the same device.
This tutorial covers:
- Basic YubiHSM 2 setup
- Connecting to YubiHSM 2
- Generating an Authkey on the device
- Generating an Asymmetric Object
- Generating a Wrapkey
- Exporting/Importing an Object under wrap
Before proceeding with this document you should be familiar with concepts such as: Sessions, Domains, Capabilities described in the Core Concepts section.
Note
The following code samples have arbitrary line-breaks to prevent them from running off the page.
Set Up the Environment
| Step 1: | Get the latest binaries from SDK download YubiHSM2/Releases. |
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| Step 2: | Install all libraries. |
| Step 3: | Make sure your device is accessible by the connector. This is accomplished either by running the connector as a superuser or by using an appropriate udev_rule. |
Start Up
To physically reset the YubiHSM 2 insert the device while holding the touch sensor for 10 seconds. The following steps use the yubihsm-connector. Connection can also be made using the direct USB mode which is explained later in this document.
| Step 1: | Start the connector. $ yubihsm-connector -d
where –
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| Step 2: | Check the status of your connector and device by using a browser to visit http://127.0.0.1:12345/connector/status. |
Set Up YubiHSM 2 Connection
| Step 1: | Start yubihsm-shell. $ yubihsm-shell
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| Step 2: | Connect to YubiHSM 2. $ yubihsm> connect
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Sessions
Many commands require a Session ID to be specified. To obtain a Session ID use the session open command followed by an Authentication Key ID and a derivation password.
By default the YubiHSM 2 comes with a pre-installed Authentication Key with Object ID 1 and derivation password password.
Open
To open a Session with this Authentication Key use:
yubihsm> session open 1 password
Created session 0
The Session ID is the number found in the line directly below a session open command.
where–
0 Is the Session ID. This value is used to address the newly created Session.
1 is the object ID of the pre-installed Authentication Key.
password is the password of the pre-installed Authentication Key.
Close
To close a Session use the command session close followed by the Session ID:
yubihsm> session close 0
where–
0 Is the Session ID.
List
To list the objects in the device use:
yubihsm> list objects 0
where–
0 Is the Session ID.
Note
If you have closed Session 0, the above command will not work. In that situation, open a new Session and use the new Session ID in the command above.
Adding a New Authentication Key
Before moving on, make sure you are familiar with concepts of Capability and Domain
| Step 1: | For our example we are going to generate an Authentication Key with selected Capabilities and Domains. Learn more about existing key Types at Objects. yubihsm> put authkey 0 2 yubico 1,2,3 generate-asymmetric-key,
export-wrapped,get-pseudo-random,put-wrap-key,import-wrapped,
delete-asymmetric-key,sign-ecdsa sign-ecdsa,
exportable-under-wrap,export-wrapped,import-wrapped password
where–
Important
Note The command above has two distinct sets of Capabilities, separated by a space. This is because Authentication Keys, in addition to having regular Capabilities, also have Capability. |
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| Step 2: | List all Objects to see the newly created Authentication Key. yubihsm> list objects 0
where–
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| Step 3: | Next, let’s start using our newly created Authentication Key to establish an encrypted Session. yubihsm> session open 2 password
Created session 1
where–
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Generate a Key for Signing
We now proceed to generate a new Asymmetric Key. In our example we will use this key to sign some data. We will also export the key under wrap to another YubiHSM, for backup purposes.
Specifically, we will ask the device to generate an Asymmetric Key with ID 100 and a given set of Domains and Capabilities. We will also specify the kind of Asymmetric Key that we would like to generate, an EC key using the NIST P-256 curve in this case.
The command is:
yubihsm> generate asymmetric 1 100 label_ecdsa_sign 1,2,3
exportable-under-wrap,sign-ecdsa ecp256
where–
generate is YubiHSM shell command.
asymmetric is the key type to be generated.
1 is the session ID.
100 is the key ID.
label_ecdsa_sign is the label for the new key object.
1,2,3 are the domains where the new key will be accessible.
exportable-under-wrap allows this key to be exported under wrap.
sign-ecdsa is allows this key to be used to perform ECDSA signature.
ecp256 specifies NIST P-256 curve for the key.
On success, we will see the message:
Generated Asymmetric key 0x0064
This signifies that an Asymmetric Key with ID 0x0064 (hexadecimal for 100) was generated.
Prepare to Sign With the New Asymmetric Key
| Step 1: | Assuming we have a file called yubihsm> sign ecdsa 1 100 ecdsa-sha256 data.txt
where–
By default the output is printed to the standard output and consists of a Base64-encoded signature like the one below. MEUCIQDrBqS04LN5YdyWGiD4iaEjfl1dn+W4cl97uM
MXDpoaiQIgEBe/G/FgP4cumnO3K2XWToAnPvnuVDOnqHPiuUS0q5g=
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| Step 2: | This behavior can be changed by using the For now we will store the signature as it is in a temporary file so that we will be able to verify it later. $ echo MEUCIQDrBqS04LN5YdyWGiD4iaEjfl1dn+W4cl97uM
MXDpoaiQIgEBe/G/FgP4cumnO3K2XWToAnPvnuVDOnqHPiuUS
0q5g= >signature.b64
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| Step 3: | Next, we will extract the public key from the Asymmetric Key on the device and write it to the file yubihsm> get pubkey 1 100 asymmetric_key.pub
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| Step 4: | We are going to use OpenSSL for the verification process. Since the signature that we created before is in Base64 format, we need to convert it first. Do so with: $ base64 -d signature.b64 >signature.bin
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| Step 5: | It is now possible to verify the signature with OpenSSL. $ openssl dgst -sha256 -signature signature.bin -verify
asymmetric_key.pub data.txt
Verified OK
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Export Under Wrap
Time to export the Asymmetric Key under wrap to a second YubiHSM 2 (in this example, we will export to the same YubiHSM for convenience).
| Step 1: | To do that we need a Wrap Key, which fundamentally is an AES key. We will use the random number generator built into the YubiHSM to generate the 16 bytes needed for an AES-128 key. yubihsm> get random 1 16
9207653411df91fd36c12faa6886d5c4
Important The result of this command (the bytes) is considered extremely sensitive data and should be stored safely, and preferably, separate from any production environment. |
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| Step 2: | We can now store the Wrap Key on the device with ID 200 by doing: yubihsm> put wrapkey 1 200 label_wrapkey 1,2,3
import-wrapped,export-wrapped sign-ecdsa,
exportable-under-wrap 9207653411df91fd36c12faa6886d5c4
Note For the upcoming |
| Step 3: | We can now export the Asymmetric Key with ID yubihsm> get wrapped 1 200 asymmetric-key 100 wrapped_asymmetric.key
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| Step 4: | We are going to re-import the Asymmetric Key on the same device so we need to first delete the existing one. yubihsm> delete 1 100 asymmetric-key
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| Step 5: | To import the wrapped EC key back into the YubiHSM use: yubihsm> put wrapped 1 200 wrapped_asymmetric.key
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