Re-DD-Hello

Posted 2020-11-22 gaonuoqi

题目地址

https://dn.jarvisoj.com/challengefiles/1.Hello.12b9bde7c0c8558a9da42aa1798cafc8

 

用IDA打开，找到算法函数

 

 写出对应脚本就可以了

start=0x0000000100000CB0
sub_100000C90=0x0000000100000C90
a=[0x41, 0x10, 0x11, 0x11, 0x1B, 0x0A, 0x64, 0x67, 0x6A, 0x68,
  0x62, 0x68, 0x6E, 0x67, 0x68, 0x6B, 0x62, 0x3D, 0x65, 0x6A,
  0x6A, 0x3D, 0x68, 0x04, 0x05, 0x08, 0x03, 0x02, 0x02, 0x55,
  0x08, 0x5D, 0x61, 0x55, 0x0A, 0x5F, 0x0D, 0x5D, 0x61, 0x32,
  0x17, 0x1D, 0x19, 0x1F, 0x18, 0x20, 0x04, 0x02, 0x12, 0x16,
  0x1E, 0x54, 0x20, 0x13, 0x14, 0x00, 0x00]


flag=‘‘

v2=(start-sub_100000C90)>>2^a[0]
for i in range(55):
        a[i]-=2
        a[i]^=v2
        v2=v2+1
        flag+=chr(a[i])

print flag