title: How to extract the digest algorithm from a X509Certificate
body: <p>I can extract the OID and the name of the signature algorithm from a <code>X509Certificate</code> instance such as <code>"SHA256WithRSA"</code> but how do i extract the name of the digest algorithm like e.g. <code>"SHA256"</code>.</p>
  
  <p>Is there a way beside a string splitting for <code>"with"</code> or a fixed mapping of the OID's?</p>
  
  <p>Side question: Would it be safe to split for <code>"with"</code>?</p>