Re: Importing a PKCS#1 RSAPublicKey structure into a gnutls_pubkey_t

[René Korthaus]

Thanks for the clarification. Then is there a reason that gnutls offers 
no method to import a PKCS#1 RSAPublicKey structure - given that it is a 
standard format and almost all smartcards speak it plus RSAPublicKey is 
very similar to RSAPrivateKey and gnutls can already decode 
RSAPrivateKey structures with _gnutls_privkey_decode_pkcs1_rsa_key. From 
the code I've seen it should be fairly easy to implement and would make 
us very happy. :)

Regards, René

Am 04.08.2012 22:31, schrieb Nikos Mavrogiannopoulos:
> On 08/03/2012 02:39 PM, René Korthaus wrote:
>
> > Hello list,
> >
> > I have a smartcard that gives me a PKCS#1 RSAPublicKey structure of the
> > public key on the card and I need to generate a X.509
> > SubjectPublicKeyInfo structure from it. I already have a C++ wrapper
> > class that uses gnutls_pubkey_export to generate the
> > SubjectPublicKeyInfo structure. The question is how to import the
> > RSAPublicKey structure right.
>
> There is no exported function in gnutls that can read the RSAPublicKey
> structure. gnutls_rsa_params_t reads the private key not the public (the
> documentation has a typo which I just fixed).
>
> You can read this DER structure by using libtasn1. Check
> lib/x509/key_decode.c, and the function _gnutls_x509_read_rsa_pubkey().
> After extracting the values you can import them using
> gnutls_pubkey_import_rsa_raw().
>
> regards,
> Nikos


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