code: public static String getAlgorithm(String oid) {
          String ret = (String)algorithmNames.get(oid);
          if (ret == null)
              return oid;
          else
              return ret;
      }
docs: Gets the algorithm name for a certain id.
  @param oid	an id (for instance "1.2.840.113549.1.1.1")
  @return	an algorithm name (for instance "RSA")
  @since	2.1.6