internal string GetEncOid()

in net/JetBrains.SignatureVerifier/src/Crypt/BC/CMSSignedHelper.cs [364:432]
63 lines of code
13 McCabe index (conditional complexity)

    internal string GetEncOid(
      AsymmetricKeyParameter key,
      string digestOID)
    {
      string encOID = null;

      if (key is RsaKeyParameters)
      {
        if (!((RsaKeyParameters)key).IsPrivate)
          throw new ArgumentException("Expected RSA private key");

        encOID = CmsSignedGenerator.EncryptionRsa;
      }
      else if (key is DsaPrivateKeyParameters)
      {
        if (digestOID.Equals(CmsSignedGenerator.DigestSha1))
        {
          encOID = CmsSignedGenerator.EncryptionDsa;
        }
        else if (digestOID.Equals(CmsSignedGenerator.DigestSha224))
        {
          encOID = NistObjectIdentifiers.DsaWithSha224.Id;
        }
        else if (digestOID.Equals(CmsSignedGenerator.DigestSha256))
        {
          encOID = NistObjectIdentifiers.DsaWithSha256.Id;
        }
        else if (digestOID.Equals(CmsSignedGenerator.DigestSha384))
        {
          encOID = NistObjectIdentifiers.DsaWithSha384.Id;
        }
        else if (digestOID.Equals(CmsSignedGenerator.DigestSha512))
        {
          encOID = NistObjectIdentifiers.DsaWithSha512.Id;
        }
        else
        {
          throw new ArgumentException("can't mix DSA with anything but SHA1/SHA2");
        }
      }
      else if (key is ECPrivateKeyParameters)
      {
        ECPrivateKeyParameters ecPrivKey = (ECPrivateKeyParameters)key;
        string algName = ecPrivKey.AlgorithmName;

        if (algName == "ECGOST3410")
        {
          encOID = CmsSignedGenerator.EncryptionECGost3410;
        }
        else
        {
          // TODO Should we insist on algName being one of "EC" or "ECDSA", as Java does?
          encOID = (string)ecAlgorithms[digestOID];

          if (encOID == null)
            throw new ArgumentException("can't mix ECDSA with anything but SHA family digests");
        }
      }
      else if (key is Gost3410PrivateKeyParameters)
      {
        encOID = CmsSignedGenerator.EncryptionGost3410;
      }
      else
      {
        throw new ArgumentException("Unknown algorithm in CmsSignedGenerator.GetEncOid");
      }

      return encOID;
    }