EasyCTF_2018: Teaching Old Tricks New Dogs
Category: Programming Points: 40 Description:
You can decode a Caesar cipher, but can you write a program to decode a Caesar cipher? Your program will be given 2 lines of input, and your program needs to output the original message. First line contains N, an integer representing how much the key was shifted by. 1 <= N <= 26 Second line contains the ciphertext, a string consisting of lowercase letters and spaces. For example:
o rubk kgyeizlYou should print
i love easyctf
ciphertext = input() plaintext = "" for c in ciphertext: if c == " ": plaintext += c continue plaintext += chr(((ord(c)-ord('a')) - N) % 26 + ord('a')) print(plaintext)
Therefore, there is no flag.