@Override
  public long keccak256OperationGasCost(
      final MessageFrame frame, final long offset, final long length) {
    return copyWordsToMemoryGasCost(
        frame,
        KECCAK256_OPERATION_BASE_GAS_COST,
        KECCAK256_OPERATION_WORD_GAS_COST,
        offset,
        length);
  }
Returns the base gas cost for external code accesses.

@return the base gas cost for external code accesses
evm/src/main/java/org/hyperledger/besu/evm/gascalculator/FrontierGasCalculator.java