Re: Accessing bignums of a RSA key with OpenSSL 3.0?

[Dr Paul Dale]

Try: include/openssl/core_names.h
The names are "n", "e" and "d" in this case.


Pauli


On 30/7/21 10:57 pm, Olivier Mascia via openssl-users wrote:

Dear all,

Testing migration to OpenSSL 3.0.
Got to update some code building a JWK (in relation to ACME LetsEncrypt 
protocols).

Having an EVP_PKEY which happens to be a RSA key, I proceeded this way (1.1.1) 
to extract the bignums needed for inclusion into the JWK:

        // Access the numerical components of the certificate RSA keys.
        BIGNUM* n;
        BIGNUM* e;
        BIGNUM* d;
        RSA_get0_key(cert.RSAkey(), &n, &e, &d);

( my cert.RSAkey() returned RSA* from my embedded EVP_PKEY* through 
EVP_PKEY_get0_RSA() )

I understand I should now start straight from the EVP_PKEY and use :

        EVP_PKEY_get_bn_param(cert.key(), "name-n?", &n);
        EVP_PKEY_get_bn_param(cert.key(), "name-e?", &e);
        EVP_PKEY_get_bn_param(cert.key(), "name-d?", &d);

( cert.key() returns EVP_KEY* )

The question is: where can I find the proper names for these bignums out of a 
RSA key?

__
Best Regards, Meilleures salutations, Met vriendelijke groeten, Mit 
freundlichen Grüßen,
Olivier Mascia