Typically, the end block is used to perform final calculations or print summaries that should appear at the end of the output stream.
通常，END代码块用于进行最终计算或者打印应该在输出流结尾处出现的汇总信息。
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The algorithm is referred to as a stream or block cipher depending on whether the algorithm transforms the message one byte at a time or a block (eight bytes) at a time.