title: How to find the matching curve name from an ECPublicKey
body: <p>Currently i'm updating my x.509 certificate library to support ECC. Most of the builders that are implemented take a publicKey and derive the algorithm and such from the key. In RSA this is simple, you check the algorithm of the key and you can verify the bit length. However with ECC the key is based on a curve, and the curve name (of course) needs to be specified in the certificate (as OID).</p>
  
  <p>The issue i'm working on right now is finding a way to come from either a java.security.interfaces.ECPublicKey or a org.bouncycastle.jce.interfaces.ECPublicKey to a curve name. (Both implementations are completely different from each other...)</p>
  
  <p>One way i can think of is getting the key's ECPoint and validate that it is on a given curve. This way i can test all supported curves, this however feels cumbersome at runtime and possibly error prone if there are points overlapping 2 or more curves.</p>
  
  <p>Another way is to get the ECCurve (bc implementation) or the EllipticCurve (jre implentation) and compare the curve details with the supported implementations. This also involves stepping through every known curve.</p>
  
  <p>Does anybody know a better way of finding the curve name based on curve or publicKey details using jre(8/9) and bc only. And what is your feeling about the first solution, how likely would it be to get false hits.</p>