Using PKINIT with ECC

[Goetz Golla]

On 1/11/24 15:41, Ken Hornstein wrote:
> But here is some snippets of the PKCS#11 code in MIT Kerberos:
>
> When specifying the search parameters to find the private key:
>
>      keytype = CKK_RSA;
>      attrs[nattrs].type = CKA_KEY_TYPE;
>      attrs[nattrs].pValue = &keytype;
>      attrs[nattrs].ulValueLen = sizeof keytype;
>      nattrs++;
>
> When setting the key signing mechanism:
>
>      /*
>       * We'd like to use CKM_SHA256_RSA_PKCS for signing if it's available, but
>       * historically many cards seem to be confused about whether they are
>       * capable of mechanisms or not. The safe thing seems to be to ignore the
>       * mechanism list, always use CKM_RSA_PKCS and calculate the sha256 digest
>       * ourselves.
>       */
>      id_cryptoctx->mech = CKM_RSA_PKCS;
>
> Those are all hardcoded use of RSA keys and signing mechanisms and it
> doesn't handle ECC at all.  So unless the Yubico library ignored the
> key type and mechanism (which I think would be extremely unlikely but
> not impossible) I suspect you were using RSA back during your original
> testing and didn't realize it.
>
> --Ken

Its good to know the reason why MIT Kerberos cannot handle EC 
certificates right now.

I know that NIST is happy with RSA 2048, but in Europe RSA >= 3072 is 
already mandatory, and this key size makes small devices like the 
Yubikeys very slow when generating the keys. In fact, Yubikeys only 
support RSA <=2048.

So is there a way to submit a feature request for ECDSA support in MIT 
Kerberos ?

-- Goetz