code: public void setKey(String key) throws CryptoException {
  		final int length = key.length();
  		if (length < KEY_MIN_LENGTH || length >= SBOX_LENGTH) {
  			throw new CryptoException("Key length has to be between {} and {}", KEY_MIN_LENGTH, (SBOX_LENGTH - 1));
  		}
  
  		final WriteLock writeLock = this.lock.writeLock();
  		writeLock.lock();
  		try {
  			this.key = StrUtil.utf8Bytes(key);
  			this.sbox = initSBox(this.key);
  		} finally {
  			writeLock.unlock();
  		}
  	}
docs: 设置密钥
  
  @param key 密钥
  @throws CryptoException key长度小于5或者大于255抛出此异常