Accessing bignums of a RSA key with OpenSSL 3.0?

[Olivier Mascia]

Thanks!

	BIGNUM* n;
	BIGNUM* e;
	BIGNUM* d;
	EVP_PKEY_get_bn_param(cert.key(), OSSL_PKEY_PARAM_RSA_N, &n);
	EVP_PKEY_get_bn_param(cert.key(), OSSL_PKEY_PARAM_RSA_E, &e);
	EVP_PKEY_get_bn_param(cert.key(), OSSL_PKEY_PARAM_RSA_D, &d);

Now, the reverse exercise for me: to create another RSA key, solely through EVP_PKEY interfaces (knowing these n, e, d parameters), I think I should go this route:

	mKey = EVP_PKEY_new();
	EVP_PKEY_set_type(mKey, some int type ?);

	EVP_PKEY_set_bn_param(mKey, OSSL_PKEY_PARAM_RSA_N, n2);
	EVP_PKEY_set_bn_param(mKey, OSSL_PKEY_PARAM_RSA_E, e2);
	EVP_PKEY_set_bn_param(mKey, OSSL_PKEY_PARAM_RSA_D, d2); 
	
But how to get the proper int type to pass to EVP_PKEY_set_type()?

Thanks all for support switching to OpenSSL 3.0.
__
Best Regards, Meilleures salutations, Met vriendelijke groeten, Mit freundlichen Grüßen,
Olivier Mascia

> Le 30 juil. 2021 à 15:07, Dr Paul Dale <pauli at openssl.org> a écrit :
> 
> 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
>> 
>> 
>