ctfshow逆向rever笔记re1 逆向签到题main page
直接ida打开就可以看到flag。可以直接找main函数。
beachhou
flag{7ujm8ikhy6}
re2
⽤ollydebug打开，我的ida不好使了。。。。
这⾥是简单的异或
msa是什么意思
DH jkwpmvez{
mqqvqxB^||zll@Jq
脚本得到密钥
s="DH~mqqvqxB^||zll@Jq~jkwpmvez{"
key=""
for c in s:
key+=chr(ord(c)^0x1f)
pb是什么意思print(key)
#[Warnning]Access_Unauthorized
[Warnning]Access_Unauthorized
程序⽤密钥对明⽂flag进⾏RC4加密，现已知密⽂和密钥，写RC4解密脚本即可得到flag ⽤winhex查看那个被加密的txt⽂档，这就是被加密的数据，放到代码的data中。what the hell 歌词
幸福 英文
C++代码：
#include<stdio.h>
void rc4_init(unsigned char* s,unsigned char* key,unsigned long Len_k)//初始化函数
{
int i =0, j =0;
char k[256]={0};
unsigned char tmp =0;
for(i =0; i <256; i++){
s[i]= i;世界末日 英语
k[i]= key[i % Len_k];
}
for(i =0; i <256; i++){
j =(j + s[i]+ k[i])%256;
tmp = s[i];
s[i]= s[j];
s[j]= tmp;
幼儿英语早教机构}
}
void rc4_crypt(unsigned char* Data,unsigned long Len_D,unsigned char* key,unsigned long Len_k)//加解密{
unsigned char s[256];
rc4_init(s, key, Len_k);
int i =0, j =0, t =0;
chartsunsigned long k =0;
unsigned char tmp;
for(k =0; k < Len_D; k++){
i =(i +1)%256;
j =(j + s[i])%256;
tmp = s[i];james white
s[i]= s[j];
s[j]= tmp;
t =(s[i]+ s[j])%256;
Data[k]= Data[k]^ s[t];
}
}
int main()
{
unsigned char key[]="[Warnning]Access_Unauthorized";
unsigned long key_len =sizeof(key)-1;
unsigned char data[]={0xC3,0x82,0xA3,0x25,0xF6,0x4C,
0x36,0x3B,0x59,0xCC,0xC4,0xE9,0xF1,0xB5,0x32,0x18,0xB1,
0x96,0xAe,0xBF,0x08,0x35};
rc4_crypt(data,sizeof(data), key, key_len);
for(int i =0; i <sizeof(data); i++)
{
printf("%c", data[i]);
}
printf("\n");
}
//flag{RC4&->ENc0d3F1le}
flag{RC4&->ENc0d3F1le}
