The reasoning for the Feistel cipher, as shown in Figure 3.6 applies in the case of
DES. We only have to show the effect of the IP and IP-1 functions. For encryption,
the input to the final IP-1 is RE16 LE16. The output of that stage is the ciphertext.
On decryption, the first step is to take the ciphertext and pass it through IP. Because
IP is the inverse of IP-1, the result of this operation is just RE16 LE16, which is
equivalent to LD0 RD0. Then, we follow the same reasoning as with the Feistel
cipher to reach a point where LE0 = RD16 and RE0 = LD16. Decryption is completed
by passing LD0 RD0 through IP-1. Again, because IP is the inverse of IP-1, passing
the plaintext through IP as the first step of encryption yields LD0 RD0, thus
showing that decryption is the inverse of encryption.
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Des Hommes et Des Dieux was released on 02/25/2011.
Des Coleman was born on March 14, 1969.
Der Ring des Nibelungen was created in 1876.
Der Tag des Gerichts was created in 1762.
The cast of Des Bishop Live at Vicar Street - 2005 includes: Des Bishop as himself