BUUCTF

BUUCTF

题目：给了两个文件一个是key.txt，一个是密文.txt

这种类型的题的原理就是将所有的字符串变成二进制数，一个字符串对应8位二进制数。

再进行加法运算：1+1=0，1+0=0，0+1=0，（每个1，0相加）

key.txt：

通过010 editor打开：

密文.txt：

 

通过010 editor打开：

        

再代入到python里面：

代码:

import libnum
a = '0110000101110011011000010110010001110011011000010111001101100100011000010111001101100100011000010111001101100100011000010111001101100100011000010111001101100100011000010111001101100100011000010111001101100100011000010111001101100100011000010111001101100100011100010111011101100101011100110111000101100110'
b = '0000011100011111000000000000001100001000000001000001001001010101000000110001000001010100010110000100101101011100010110000100101001010110010100110100010001010010000000110100010000000010010110000100011000000110010101000100011100000101010101100100011101010111010001000001001001011101010010100001010000011011'
c = ''

for i in range(len(a)):
    if(a[i] == b[i]):
        c+='0'
    else:
        c+='1'
print(c)
print(libnum.b2s(c))

 最后解出falg