[WeChall] Training: Crypto - Caesar I (Crypto, Training)_ctf crypto

本文链接：https://blog.youkuaiyun.com/itfcheins/article/details/40948203

本文介绍了一种简单的Caesar密码加密原理及其实现方法，并通过Python脚本演示了如何解密此类密码。读者将了解字母替换的基本过程以及如何逆向操作来揭示隐藏的消息。

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Question:

Crypto - Caesar I

As on most challenge sites, there are some beginner cryptos, and often you get started with the good old caesar cipher.
I welcome you to the WeChall style of these training challenges :)

Enjoy!

IWT FJXRZ QGDLC UDM YJBEH DKTG IWT APON SDV DU RPTHPG PCS NDJG JCXFJT HDAJIXDC XH CTGHPCDRCVDG

Solution:

It's a simply example of caesar cipher, When encrypting, a person looks up each letter of the message in the "plain" line and writes down the corresponding letter in the "cipher" line. Deciphering is done in reverse, with a right shift of 3. I decode this By python:

#!/usr/bin/env python 
f = file('key.txt','r+')
s = f.read()
l = []
for i in s:
    l.append(i)
leng = len(l)
print 'l:'%l
for i in range(leng):
l[i] = ord(l[i])

new = []
for i in l:
    new.append(chr(i+3))

cryptos = ""
for i in new:
    cryptos += i

print cryptos.lower()

key.txt is the string to Decode.and result s :

thewquickwbrownwfoxwjumpswoverwthewlazywdogwofwcaesarwandwyourwuniquewsolutionwiswnersanocngor

ignore the char 'w', we can see the words:

the quick brown fox jumps over the lazy dog of caesar and your unique solution is nersanocngor

submit the string "nersanocngor", SUCCESS!