PKCS#11 URL Generation

Various applications use openssl to handle e.g., TLS certificates. This concept mostly allows simply replacing a file-path (for the secret) with a so-called PKCS#11 URL to use a secret from a e.g., Nitrokey.

Preparation

• ensure openssl is installed

• ensure openssl can use the PKCS#11 engine by installing libengine-pkcs11-openssl

• install opensc and gnutls-bin for necessary tools

• verify that your needed keys and/or certificates are available on your Nitrokey using pkcs15-tool -D

• if you want to use ECC keys/mechanisms through libengine-pkcs11-openssl, you’ll have to ensure its version is at least 0.4.10

List and Generate PKCS#11 URLs

Use the following command to get a list of available tokens (Nitrokeys):

p11tool --list-tokens

Choose the token (Nitrokey) URL you want to generate URL tokens for and use it like this:

p11tool --list-all <token-url>

# example:
# p11tool --list-all "pkcs11:model=PKCS%2315%20emulated;manufacturer=www.CardContact.de;serial=DENK0123123;token=UserPIN%20%28SmartCard-HSM%29"

If you inspect the tail of the URL you’ll recognize: label, id and more, these can be partly removed as long as the necessary objects can be uniquely identified using the resulting URL, see TLS Apache2 Configuration for an example using id only.