[问题] 密码学 3DES 中间的步骤为何用decryption

楼主: woody3724 (woody)   2014-03-28 22:48:07
密码学
3DES的加密三个步骤是
E(加密) -> D(解密) -> E(加密)
原文书题到 (以下英文撷取自课本原文书)
There is no cryptographic significance to the use of decryption for the second
stage of 3DES encryption. Its only advantage is that it allows users of 3DES
to decrypt data encrypted by users of the older single DES:
C = E( K1,D( K1,E( K1, P ) ) ) = E[K,P]
where C = ciphertext
P= plaintext
E[K,X] = encryption of X using key K
D[K,Y] = decryption of Y using key K
看完这段还是不懂为什么中间的步骤要用解密
尤其是older single DES不懂
谢谢
作者: suhorng ( )   2014-03-28 22:53:00
因为key取一样就可以变 (1)DES一种电路,两种用法,赚!
楼主: woody3724 (woody)   2014-03-29 16:18:00
感谢楼上!!!!

Links booklink

Contact Us: admin [ a t ] ucptt.com