@param certs a PKCS#7 GetCACert response
@param ca_fingerprint CFDataRef with CA fingerprint. Size indicates hash type. Recognises SHA-1 and MD5.
@param ca_certificate SecCertificateRef CA certificate
- @param ra_certificate SecCertificateRef RA certificate. Use both for signing and encryption unless ra_encryption_certificate is also returned.
+ @param ra_signing_certificate SecCertificateRef RA certificate. Use both for signing and encryption unless ra_encryption_certificate is also returned.
@param ra_encryption_certificate SecCertificateRef RA encryption certificate. Returned if there isn't an RA certificate that can both sign and encrypt.
@result status errSecSuccess on success.
*/