Re: [Ejbca-develop] Why ECDSA keys require a minimum size of 224 bits for Crypto Token key pair generation?

[Andreas K. <ku...@tr...>]

Hi Jaime,

interesting finding! Due to https://safecurves.cr.yp.to/ there are at
least two curves with (slightly) shorter key length. On the other hand
the NIST-224 is considered insecure ...

Are there any specific reasons for implementing this restriction?

Greetings,

Andreas
> In EJBCA 6.10.1.2+, if you create a Crypto Token from the Admin GUI and
> then you try to generate an EC keypair for it, you find that certain curves
> are not availabe, e.g. B-163, even when the documentation indicates support
> for them (see
> https://www.ejbca.org/docs/ECDSA_Keys_and_Signatures.html#src-16224742_id-.ECDSAKeysandSignaturesv6.12.0-Named_curves
> ).
>
> Looking at the source code I can see the cause for it is in the following
> method, org.cesecore.keys.util.KeyTools#checkValidKeyLength:
>
> public static void checkValidKeyLength(final String keyAlg, final int len)
> throws InvalidKeyException {
>   ...
>   if (*isEcdsa *|| isGost3410 || isDstu4145) {
>     ...
>     if ((len > 0) && (*len < 224)*) {
>       final String msg =
> intres.getLocalizedMessage("catoken.invalidkeylength", "ECDSA", "224",
> Integer.valueOf(len));
>       *throw new InvalidKeyException(msg);*
>     }
>   } ...
> }
>
> But, why is it so?. Are there potentials problems with EC curves with a key
> size smaller than 224 bits?.
>
> PS: I'm a total ignorant of EC cryptography.
>
>
> _______________________________________________
> Ejbca-develop mailing list
> Ejb...@li...
> https://lists.sourceforge.net/lists/listinfo/ejbca-develop


-- 
Andreas Kühne 
phone: +49 177 293 24 97 
mailto: ku...@tr...

Trustable Ltd. Niederlassung Deutschland Gartenheimstr. 39C - 30659 Hannover Amtsgericht Hannover HRB 212612

Director Andreas Kühne

Company UK Company No: 5218868 Registered in England and Wales