Write a program to perform encryption and decryption using wrapper class Encryption phase with shift n = En (x) = (x+n)mod 26Decryption phase with shift n = Dn (x) = (x-n)mod 26ExamplesText : ABCDEFGHIJKLMNOPQRSTUVWXYZShift : 23Cipher : XYZABCDEFGHIJKLMNOPQRSTUVWinput-output format Text : ATTACKATONCE(input)Shift : 4(input)Cipher : EXXEGOEXSRGI(output)ATTACKATONCE
Question
Write a program to perform encryption and decryption using wrapper class Encryption phase with shift n = En (x) = (x+n)mod 26Decryption phase with shift n = Dn (x) = (x-n)mod 26ExamplesText : ABCDEFGHIJKLMNOPQRSTUVWXYZShift : 23Cipher : XYZABCDEFGHIJKLMNOPQRSTUVWinput-output format Text : ATTACKATONCE(input)Shift : 4(input)Cipher : EXXEGOEXSRGI(output)ATTACKATONCE
Solution
Here is a simple Python program that performs Caesar cipher encryption and decryption:
def encrypt(text, shift):
result = ""
for i in range(len(text)):
char = text[i]
if (char.isupper()):
result += chr((ord(char) + shift - 65) % 26 + 65)
else:
result += chr((ord(char) + shift - 97) % 26 + 97)
return result
def decrypt(text, shift):
result = ""
for i in range(len(text)):
char = text[i]
if (char.isupper()):
result += chr((ord(char) - shift - 65) % 26 + 65)
else:
result += chr((ord(char) - shift - 97) % 26 + 97)
return result
text = "ATTACKATONCE"
shift = 4
print("Text : " + text)
print("Shift : " + str(shift))
print("Cipher: " + encrypt(text, shift))
cipher = "EXXEGOEXSRGI"
print("Decipher: " + decrypt(cipher, shift))
This program defines two functions, encrypt and decrypt, which perform the Caesar cipher encryption and decryption respectively. The encrypt function shifts each character in the input text to the right by a given number (the shift), wrapping around at the end of the alphabet. The decrypt function does the opposite, shifting each character to the left by the shift. The ord function is used to get the ASCII value of a character, and the chr function is used to get the character that corresponds to an ASCII value. The % 26 operation ensures that the shift wraps around at the end of the alphabet.
Similar Questions
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