题目

题干链接:http://www.shiyanbar.com/ctf/20

加密密文：afZ_r9VYfScOeO_UL^RWUc
格式：flag{ }

解法：明文应该是flag开头的，想办法将afZ_变到flag

观察发现编程ascii码后有一定规律

1.代码：

def change(c,i):
    num = ord(c)+i
    return chr(num)

def kaisa_jiami(string,i):
    string_new = ''
    for s in string:
        string_new += change(s,i)
        i+=1
    print(string_new)
    return string_new

def kaisa_jiemi(string):
    for i in range(25):
        for alpha in kaisa_jiami(string,i):
            print(ord(alpha), end=' ')
            i += 1
        print("")
def main():
    kaisa_jiemi("afZ_r9VYfScOeO_UL^RWUc")


if __name__ == '__main__':
    main()

2.运行结果：