1. The ciphertext CRWWZ was encrypted using an affine cipher. The plaintext starts with ha. Decrypt the message. 2. Decrypt the following Caesar encryptions by trying the various possible shifts until you obtain readable text. 'NJACQYAXERMNBNWXDPQCXBJCRBOHNENAHVJWBWNNMBKD- CWXCNENAHVJWBPANNM’ 3. (a) Suppose that you have an alphabet of 26 letters how many possible simple substitution ciphers are there? (b) Determine the number of keys in an Affine Cipher in an alphabet system with i. 32 alphabets ii. 100 alphabets

1. The ciphertext CRWWZ was encrypted using an affine cipher. The plaintext starts with ha. Decrypt the message. 2. Decrypt the following Caesar encryptions by trying the various possible shifts until you obtain readable text. 'NJACQYAXERMNBNWXDPQCXBJCRBOHNENAHVJWBWNNMBKD- CWXCNENAHVJWBPANNM’ 3. (a) Suppose that you have an alphabet of 26 letters how many possible simple substitution ciphers are there? (b) Determine the number of keys in an Affine Cipher in an alphabet system with i. 32 alphabets ii. 100 alphabets

Elements Of Modern Algebra

8th Edition

ISBN:9781285463230

Author:Gilbert, Linda, Jimmie

Publisher:Gilbert, Linda, Jimmie

Chapter2: The Integers

Section2.8: Introduction To Cryptography (optional)

Problem 15E: a. Excluding the identity cipher, how many different translation ciphers are there using an alphabet...

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Suppose the alphabet consists of a through z, in natural order, followed by a blank and then the digits 0 through 9, in natural order. Associate these "letters" with the numbers 0,1,2,...,36, respectively, thus forming a 37-letter alphabet, D. Use the affine cipher to decipher the message X01916R916546M9CN1L6B1LL6X0RZ6UII if you know that the plaintext message begins with "t" followed by "h". Write out the affine mapping f and its inverse.
Suppose that in an RSA Public Key Cryptosystem, the public key is. Encrypt the message "pay me later” using two-digit blocks and the -letter alphabet from Example 2. What is the secret key? Example 2 Translation Cipher Associate the letters of the "alphabet" with the integers. Let and define the mapping by where is the key, the number of positions from the plaintext to the ciphertext. If our alphabet consists of through, in natural order, followed by a blank, then we have "letters" that we associate with the integers as follows:
a. Excluding the identity cipher, how many different translation ciphers are there using an alphabet of n "letters"? b. Excluding the identity cipher, how many different affine ciphers are there using an alphabet of n "letters," where n is a prime?
Suppose that in an RSA Public Key Cryptosystem, the public key is e=13,m=77. Encrypt the message "go for it" using two-digit blocks and the 27-letter alphabet A from Example 2. What is the secret key d? Example 2 Translation Cipher Associate the n letters of the "alphabet" with the integers 0,1,2,3.....n1. Let A={ 0,1,2,3.....n-1 } and define the mapping f:AA by f(x)=x+kmodn where k is the key, the number of positions from the plaintext to the ciphertext. If our alphabet consists of a through z, in natural order, followed by a blank, then we have 27 "letters" that we associate with the integers 0,1,2,...,26 as follows: Alphabet:abcdef...vwxyzblankA:012345212223242526
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Suppose that in an RSA Public Key Cryptosystem. Encrypt the message "algebra" using the -letter alphabet from Example 4. Use two-digit blocks. Use three-digit blocks. What is the secret key?
Suppose that in an RSA Public Key Cryptosystem. Encrypt the message "pascal" using the -letter alphabet from Example 4. Use two-digit blocks. Use three-digit blocks. What is the secret key?
Suppose the alphabet consists of a through, in natural order, followed by a blank, a comma, and a period, in that order. Associate these "letters" with the numbers, respectively, thus forming a -letter alphabet,. Use the affine cipher to decipher the message if you know that the plaintext message begins with "" and ends with ".". Write out the affine mapping and its inverse.
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Use the Caesar cipher (shift of 3 places) to encryptBRAVE