UTCTF2020-babymips

整个程序是用C++编写的，但不难看出代码的意思，且逻辑简单，整个分析都在图中。

对应解题代码如下：

#include <stdio.h>

int main(){
	
	//len = 78
	unsigned char a1[] ={
		0x62, 0x6C, 0x7F, 0x76, 0x7A, 0x7B, 0x66, 0x73, 0x76, 0x50, 
		0x52, 0x7D, 0x40, 0x54, 0x55, 0x79, 0x40, 0x49, 0x47, 0x4D, 
		0x74, 0x19, 0x7B, 0x6A, 0x42, 0x0A, 0x4F, 0x52, 0x7D, 0x69, 
		0x4F, 0x53, 0x0C, 0x64, 0x10, 0x0F, 0x1E, 0x4A, 0x67, 0x03, 
		0x7C, 0x67, 0x02, 0x6A, 0x31, 0x67, 0x61, 0x37, 0x7A, 0x62, 
		0x2C, 0x2C, 0x0F, 0x6E, 0x17, 0x00, 0x16, 0x0F, 0x16, 0x0A, 
		0x6D, 0x62, 0x73, 0x25, 0x39, 0x76, 0x2E, 0x1C, 0x63, 0x78, 
		0x2B, 0x74, 0x32, 0x16, 0x20, 0x22, 0x44, 0x19
	};
	unsigned char a2[78] = {0};
	
	for(int i=0;i<78;i++){
		a2[i] = a1[i] ^ (i+23);
		printf("%c",a2[i]);
	}
	
}
#utflag{mips_cpp_gang_5VDm:~`N]ze;\)5%vZ=C'C(r#$q=*efD"ZNY_GX>6&sn.wF8$v*mvA@'}
#没错！这个乱七八糟的就是flag