Book: Cryptology Theory and Practice (3rd Edition) Page: 114 Exercise: 3.1 Note:

Question

Book: Cryptology Theory and Practice (3rd Edition) Page: 114 Exercise: 3.1 Note: To get the points from answering this answer the complete exercise, not just part of it. Let y be the output of Algorithmn 3.1 on input x, w here nts and mp are defined as in Example 3.1. In other words, SPN(x, Tur r+1 where (K ...,KNr 1) is the key schedule. Find a substitution ns. and a permutation np such that L1)) Nr+1. ,SPN y, Trs where each L' is a permutation of K Algorithm 3.1 SPN(x, Trs, map, (K1,...,KNr 1)), for r 1 to Nr 1 for i 1 to m do do vrkt> np(1), u mp (m) Nr Nr-1 Nr D K for i 1 to m Nr Nr do v TTS (u

Explanation / Answer

Secret key and public key systems are often used together, such as the AES secret key and the RSA public key. The secret key method provides the fastest decryption, and the public key method provides a convenient way to transmit the secret key. This is called a "digital envelope." For example, the PGP e-mail encryption program uses one of several public key methods to send the secret key along with the message that has been encrypted with that secret key (see PGP).

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

---