What is a characteristic of using the Electronic Code Book mode of DES encryption?以下哪一项特征是使用DES中电子密码本？（）

• A、Repetitive encryption obscures any repeated patterns that may have been present in the plaintext.反复加密以掩盖任何可能在明文出现的重复模式
• B、The previous DES output is used as input.之前的DES加密输出被用来作为输入
• C、Individual characters are encoded by combining output from earlier encryption routines with plaintext.单个字符从之前明文加密程序的结合输出来进行编码
• D、A given block of plaintext and a given key will always produce the same ciphertext.一个给定的明文和一个给定的密钥将总是产生相同的密文。