4. Decipher the following ciphertext, which was enciphered with the Caesar cipher: TEBKFKQEBZLROPBLCERJXKBSBKQP, using the statistical cryptoanalysis and the 1-gram model of English (see the table below). Write a program to calculate the correlation (i) for 0 ≤ i ≤ 25 to help identify the key and the plaintext. a b с d e f 61) 0.080 0.015 0.030 0.040 0.130 0.020 0.015 h i k 0.060 j 0.005 1 0.065 0.005 0.035 m 0.030 n 0 9 Р 0.020 r 0.070 S 0.080 0.002 0.065 0.060 t u V X y N 0.090 0.030 0.010 0.015 0.005 0.020 0.002

4. Decipher the following ciphertext, which was enciphered with the Caesar cipher: TEBKFKQEBZLROPBLCERJXKBSBKQP, using the statistical cryptoanalysis and the 1-gram model of English (see the table below). Write a program to calculate the correlation (i) for 0 ≤ i ≤ 25 to help identify the key and the plaintext. a b с d e f 61) 0.080 0.015 0.030 0.040 0.130 0.020 0.015 h i k 0.060 j 0.005 1 0.065 0.005 0.035 m 0.030 n 0 9 Р 0.020 r 0.070 S 0.080 0.002 0.065 0.060 t u V X y N 0.090 0.030 0.010 0.015 0.005 0.020 0.002

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Experiment 1: IMPLEMENTATION OF CAESAR CIPHER Objective: To implement the simple substitution technique named Caesar cipher using C+ language. Theory: To enerypt a message with a Caesar cipher, each letter in the message is changed using a simple rule: shift by three. Each letter of the message is shifted a fixed distance (3 for example) down the alphabet, A becomes D, B becomes E, and so on. For the last letters, we can think of alphabet as a circle and "wrap around", W becomes Z. X becomes A, Y becomes B, and Z becomes C. To change a message back, cach letter is replaced by the one three before it. Example ABCDEFGHIJKLMNOPQRSTUVWXYZ t t t t t t t t ttt t t t t t t tt t t t t t t ft DEFGHIJKLMNOPQRSTUVW XY Z ABc) digorithm STEP-1: Read the plain text from the user. STEP-2: Read the key value from the user. STEP-3: If the key is positive then encrypt the text by adding the key with each character in the plain text. STEP-4: Else subtract the key from the plain text. STEP-5: Display the…
Modify the codes with the same problem. 1.) decrypt code = input("Enter the coded text: ") distance = input("Enter the distance value: ") plainText = '' for ch in code: ordValue = ord(ch) cipherValue = ordValue - distance if cipherValue < ord('a'): cipherValue = ord('z') - (distance) - \ (ordValue - ord('a') - 1) plainText += chr(cipherValue) print(plainText) 2.) Encrypt plainText = input("Enter a one-word, lowercase message: ") distance = int(input("Enter the distance value: ")) code = "" for ch in plainText: ordValue = ord(ch) cipherValue = ordValue + distance if cipherValue > ord('z'): cipherValue = ord('a') + distance - \ (ord('z') - ordValue + 1) code += chr(cipherValue) print(code)
Encrypt the message 001100001010 using Simplified DES (as defined in the book in section 4.2) and key 111000101. [Hint: After one round, the output is 001010010011.] If you do this by hand, it is sufficient to only do 3 rounds instead of 8 rounds. If you write a program, you should carry out the full implementation. Please provide your code.
Substitution ciphers are encryption/decryption algorithms that replace one letter or number with another. The first attested use of a substitution cipher in military affairs was by Julius Caesar, described by him in Gallic Wars (cf. Kahn pp83-84). In caesar cipher , you replace each letter by 3rd letter on. If it is out of bound (later than Z), then round to the head (letter A) and continue the shift. For example:meet me after the toga party PHHW PH DIWHU WKH WRJD SDUWB Please write a program in Java to implement the Caesar Cipher: a. Implement the encryption algorithm. Ask the user to input one all lower case normal sentence (called plaintext) using the nextLine method, and then output the encrypted text (called ciphertext). b. Implement the decryption algorithm. Ask the user to input one encrypted sentence (i.e. ciphertext) using the nextLine method, and then output the decrypted text (i.e. plaintext).
Implement the first round of AES ( Advanced Encryption Standard ) in python. Given a message with 128 bits, two subkeys subkey0 and subkey1, your program should be able to perform one AddKey before Round 1 and the corresponding operations (SubBytes, ShiftRows, Mix-Columns, and AddKey) in Round 1, and output the result of the encryption after Round 1.
You may use a software to do calculations but you have to write down the details. The correspondence of letters table: A B C D E F GH I J K L M 01 02 03 04 05 06 07 08 09 10 11 12 13 N O P Q 14 15 16 R S TU V W X Y Z space 17 18 19 20 21 22 23 24 25 26 00 6. Implement the RSA cryptosystem with a sofeware of your choice. (Specifica- tion: Find two probable primes p 3p/2. Submit the primes p and q. I will encode a message with a key e and return the encrypted message and the key e to you. Then you will be asked to decode the message.)
The Reflection algorithm can be used to encrypt a C-string (character array terminated with the null character) before it is transmitted over the Internet. The Reflection algorithm works as follows: Each letter in the message is converted to the letter in that is 13 positions to the right of that letter in the English alphabet. If the end of the alphabet is reached, counting continues from the first letter in the alphabet. The case of the letters must be maintained. For example,'M' →'Z', 'x' → 'k', 'A' → 'N'The numeric characters ('0' to '9') are shifted 5 positions to the right of that number in the character set '0' to '9'. If ‘9’ is reached, counting continues from ‘0’. For example,'0' → '5', '2' →'7', '8' → '3' All other characters are left as they are. a) What would the following string be encrypted to by the Reflection algorithm?“Call me at 662-2002 Ext 85393” b) Write a function, getPosition, which finds the position of a letter in the alphabet regardless of the case of the…
Encrypt Caesar cipher is a kind of substitution cipher. Instead of using a substitution table, the alphabets are rotated by a number (a key). For example, if the key is 3, plaintext alphabet a would become d, and plaintext alphabet z would become c. Write a program that implements the Caesar Cipher. You program will first prompt for the key and then for the mode (E for encryption and D for decryption) and finally for the message to be encrypted / decrypted. Your program will then output the encryption / decryption message. For this question, the input message may consists of any character, the program should encrypt or small letter case a to z only. All other characters should be kept intact after encryption or decryption.
A Caesar cipher is a simple substitution cipher based on the idea of shifting each letter of the plaintext message a fixed number (called the key) of positions in the alphabet. For example, if the key value is 2, the word "Sourpuss" would be encoded as "Uqwtrwuu." The original message can be recovered by “reencoding" it using the negative of the key. Write a program that can encode and decode Caesar ciphers. The in- put to the program will be a string of plaintext and the value of the key. The output will be an encoded message where each character in the orig- inal message is replaced by shifting it key characters in the Unicode char- acter set. For example, if ch is a character in the string and key is the amount to shift, then the character that replaces ch can be calculated as: chr (ord (ch) + key). 62
Problem 1.Write computer programs for the Substitution Cipher based on Z29 which is corresponding to 26 alphabetic characters (0 - 25), space (26), and “, ” (27) “.”(28).The key is a random permutation π on Z29. Write down encryption and decryptionprograms. For the encryption, the plaintext and the key need to be input. To inputthe key, use the permutation of 0, 1, . . . , 28. The plaintext should be input as Englishletters. The out put will be the ciphertext which is also English letters. Select aparagraph of text which contains more than 25 words (I don’t think any two peoplewill choose a same paragraph if they choose independently) and encrypt it using yourencryption algorithm. Then use your decryption program to check the correctness.You can use Java. Record your plaintext, ciphertext and the key π in your answer sheet.
please code in python Implement an encryption function that tests that input 0xADE1 yields ciphertext (188, 153). You may hard-code these values for testing. Do NOT use ANY string/character manipulation or arithmetic functions to implement your solution.
Python The Dan Cipher works like this: shift the first lowercase character to the right by 1, the second lowercase character to the right by 2, and so on. Characters that are not lowercase characters are not changed. Write a program that takes a string and prints the result of applying the Dan Cipher.