1 permutation ciphers a k a transposition ciphers are another class of simple crypt 5346762

(1) Permutation Ciphers (a.k.a. Transposition Ciphers) are another class of simple cryptosystems. For this
we use the functions apply(.,.) and inv(.) from Homework 4; copy these two functions into your le as
auxiliary functions.
(1.a) De ne a function encr(k,m), where the message m is any string over the characters a…zA…Z, and
where the key k is a permutation. When len(m) is not a multiple of len(k) we append (a minimum number of)
Z's to m to make len(m) a multiple of len(k). In the encryption, m is subdivided into successive chunks of length
len(k), and the permutation k is applied to each chunk. The number of chunks is ceil(len(m)/len(k)).
(1.b) De ne a decryption function decr(k,c), which inverts the encryption. Here, c is any string over the
characters a…zA…Z, such that len(c) is a multiple of len(k).
(1.c) As comments, answer the following:
Give the encryption of the following text, with key [3, 2, 4, 1, 0] :
Decrypt the following cipher with the key [6, 1, 0, 2, 7, 4, 5, 3]:

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