code: public static String toHexString(final PrivateKey privateKey, final boolean lowerCase)
  	{
  		final String hexString = HexExtensions.toHexString(privateKey.getEncoded(), lowerCase);
  		return hexString;
  	}
docs: Transform the given {@link PrivateKey} to a hexadecimal {@link String} value.
  
  @param privateKey
  the private key
  @param lowerCase
  the flag if the result shell be transform in lower case. If true the result is
  @return the new hexadecimal {@link String} value.