Nitrokey HSM and Certificate Export


We’ve generated an ECC keypair within our Nitrokey HSM and for some reason it is failing to be parsed by openssl. We used the “Export Certificate” option from the drop-down available in SCSH3’s GUI.

Are we missing something here? Should we use the X509CA/ca.js script to export the self-signed certificate?

The certificate also looks a bit weird from what I have seen in past ECC keys.

$ cat cert.pem
$ openssl asn1parse -in cert.pem
    0:d=0  hl=4 l= 493 cons: appl [ 7 ]
    4:d=1  hl=5 l= 403 cons: appl [ 33 ]
    9:d=2  hl=5 l= 331 cons: appl [ 78 ]
   14:d=3  hl=3 l=   1 prim: appl [ 41 ]
   18:d=3  hl=2 l=  16 prim: appl [ 2 ]
   36:d=3  hl=5 l= 285 cons: appl [ 73 ]
   41:d=4  hl=2 l=  10 prim: OBJECT            :
   53:d=4  hl=2 l=  32 prim: cont [ 1 ]
   87:d=4  hl=2 l=  32 prim: cont [ 2 ]
  121:d=4  hl=2 l=  32 prim: cont [ 3 ]
  155:d=4  hl=2 l=  65 prim: cont [ 4 ]
  222:d=4  hl=2 l=  32 prim: cont [ 5 ]
  256:d=4  hl=2 l=  65 prim: cont [ 6 ]
  323:d=4  hl=2 l=   1 prim: cont [ 7 ]
  326:d=3  hl=3 l=  16 prim: appl [ 32 ]
  345:d=2  hl=3 l=  64 prim: appl [ 55 ]
  412:d=1  hl=2 l=  16 prim: appl [ 2 ]
  430:d=1  hl=3 l=  64 prim: appl [ 55 ]

When Nitrokey HSM 2 (or rather Smartcard-HSM SIM Card inside of it) generates a key-pair, it just does that - no X.509 certificate you probably expect is generated automatically. This makes sense, since you probably want that certificate to be signed by some other certificate authority. To do this, just create a certificate signing request using the key generated on the HSM and pass it over to the certificate authority of your choice.

The certificate you are seing right now comes in a format defined in BSI TR-03110 Part 3 - if I am not mistaken the tags are described in the section “D.2. Data objects” and explanation of each of them is elsewhere in the document.

The purpose of this is to have a Card Verifiable Certificate - it certifies that “this key belongs to Nitrokey HSM serial number DENKxxxyyyy0000. This Nitrokey HSM key has been signed by central Nitrokey authority” etc. - see [Nitrokey HSM] What are C.DevAut and C.DICA? - #2 by sc-hsm for some details.

If you upload X.509 certificate for the key, this CV certificate gets replaced.

See also Generating an attestation certificate on the Nitrokey HSM 2