2021-03-14

vnctf2021逆向wp

VNCTF 2021

[rev]FilpGame

v8表示奇偶字节不同处理
成功结果为word_40301c全部为-1，长度为0x20，flag为输入的md5
处理了214次
v4+16*v5为递增数列，由此可见,v5需要递增，v5不变时v4才需要递增
根据数组，每次翻转的位只会是(v5-1,v4)(v5,v4)(v5,v4-1)(v5,v4+1)(v5+1,v4)
cnt为奇数时才会翻转，毕竟需要v4和v5
由于v4、v5都是uint32，所以范围为0~15

算法：当v5=2时，0号字必须是-1，这样v5=1时只会出现有限数量的方案，以此类推，可以进行DFS

#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <math.h>
#include "defs.h"
// #include <setimp.h>
uint16_t wa[] = {48885, 35772, 41193, 29456, 55568, 41901, 52406, 19934, 13388, 15318, 26385, 34447, 7290, 33829, 27405, 6988};
int32_t d_40212c[]={-1,0,0,0,1};
int32_t d_402140[]={0,0,-1,1,0};
void printArray(const char *name,uint8_t *v,size_t len) 
{
    printf("========%s=========\n",name);
    for(size_t i=0;i<len;i++){
        printf("0x%02X,",v[i]);
    }
    printf("\n=================\n");
}
char toHex(uint32_t a){
    if(a<=9)return a+'0';
    else return a+55;
}
void dfs(uint16_t *state,size_t start,size_t i,char *flag){
    if(i==16){
        if(start>=1&&state[start-1]!=0xffff){
            return;
        }
        start+=1;
        i=0;
    }
    if(start==16){
        if(state[start-1]==0xffff){
            printf("%ld: %s\n",strlen(flag),flag);
            fflush(stdout);
            exit(0);
        }
        return;
    }
    if(strlen(flag)>214)return;
    uint16_t *nstate = (uint16_t*)alloca(sizeof(wa));
    memcpy(nstate,state,sizeof(wa));
    uint32_t v12,v13;
    for(size_t j=0;j<5;j++){
        v12=d_40212c[j]+i;
        v13=d_402140[j]+start;
        if(v12<=0xf&&v13<=0xf){
            nstate[v13]^=1<<(15-v12);
        }
    }
    size_t len = strlen(flag);
    // 优先寻找步数少的。。
    uint16_t *nnstate=(uint16_t*)alloca(sizeof(wa));
    char *nnflag = (char*)alloca(len+1);
    memcpy(nnflag,flag,len+1);
    memcpy(nnstate,state,sizeof(wa));
    dfs(nnstate,start,i+1,nnflag);

    char *nflag=(char*)alloca(len+3);
    memcpy(nflag,flag,len+1);
    nflag[len]=toHex(i);
    nflag[len+1]=toHex(start);
    nflag[len+2]=0;
    dfs(nstate,start,i+1,nflag);
}
int main(){
    char flag[]="";
    dfs(wa,0,0,flag);
    return 0;
}

先使用的python，发现效率不够，直接上c。。虽然剪枝了，也是花了不少时间

import hashlib
import base64
import sys
print(hashlib.md5(b'2050608090A0B0C0D02131417191A1B1527282B2D2E2F213234363B3D36494C4D4E415456575C5D5E50626566686C6F6071787B7C72838587898C8D81949596999B9C9F95A8AAAEA0B1B3B4B7B1C2C3C4C6C9CBCEC0D4D7D9DBDCDED0E1E3E4E5E6E8E9ECEEEFE3F7F8FBF').hexdigest())

[rev]Crackme2

调用了Native层函数stringFromJNI()，打开JNI_OnLoad，初始化了一个128位的数字，没有更换native函数

分析结果

jstring __fastcall Java_com_ctf_crackme_MainActivity_stringFromJNI(JNIEnv *a1, __int64 a2, jstring a3)
{
  const char *input; // x23
  jsize lenOfInput; // w21
  char *input2; // x20
  _BYTE *v8; // x1
  int v9; // w8
  unsigned int v10; // w21
  unsigned __int8 *v11; // x0
  jstring v12; // x0
  jstring v13; // x19
  __int64 v15; // [xsp+0h] [xbp-E0h] BYREF
  char key[20]; // [xsp+8h] [xbp-D8h] BYREF
  int v17; // [xsp+1Ch] [xbp-C4h] BYREF
  char v18; // [xsp+20h] [xbp-C0h] BYREF
  _BYTE v19[7]; // [xsp+21h] [xbp-BFh] BYREF
  _BYTE *v20; // [xsp+30h] [xbp-B0h]
  char v21[4]; // [xsp+38h] [xbp-A8h] BYREF
  _BYTE v22[116]; // [xsp+3Ch] [xbp-A4h] BYREF

  *(_QWORD *)&v22[108] = *(_QWORD *)(_ReadStatusReg(ARM64_SYSREG(3, 3, 13, 0, 2)) + 40);
  input = (*a1)->GetStringUTFChars(a1, a3, 0LL);
// ...
// 不是key，实际上保存着AES的结构信息
  sub_428C4(key, 128LL);
  // AES加密函数，后面发现v22是key，可以在此处下断点，调试v22
  v11 = (unsigned __int8 *)sub_42944(key, input2, v10, v22, &v17);
  // 下面是比对，xmmword_C80F0就是JNI_OnLoad初始化的数字，就是按字节比对
  if ( (unsigned __int8)xmmword_C80F0 == *v11
    && __PAIR64__(BYTE2(xmmword_C80F0), BYTE1(xmmword_C80F0)) == __PAIR64__(v11[2], v11[1])
    && __PAIR64__(BYTE4(xmmword_C80F0), BYTE3(xmmword_C80F0)) == __PAIR64__(v11[4], v11[3])
    && __PAIR64__(BYTE6(xmmword_C80F0), BYTE5(xmmword_C80F0)) == __PAIR64__(v11[6], v11[5])
    && __PAIR64__(BYTE8(xmmword_C80F0), BYTE7(xmmword_C80F0)) == __PAIR64__(v11[8], v11[7])
    && __PAIR64__(BYTE10(xmmword_C80F0), BYTE9(xmmword_C80F0)) == __PAIR64__(v11[10], v11[9])
    && __PAIR64__(BYTE12(xmmword_C80F0), BYTE11(xmmword_C80F0)) == __PAIR64__(v11[12], v11[11])
    && __PAIR64__(BYTE14(xmmword_C80F0), BYTE13(xmmword_C80F0)) == __PAIR64__(v11[14], v11[13])
    && HIBYTE(xmmword_C80F0) == v11[15] )
  {
    v12 = (*a1)->NewStringUTF(a1, "Success");
  }
  else
  {
    v12 = (*a1)->NewStringUTF(a1, "Fail");
  }
  v13 = v12;
  if ( (v18 & 1) != 0 )
    operator delete(v20);
  return v13;
}

下面是AES加密函数

__int64 __fastcall sub_42944(_DWORD *key, const char *input, size_t len, __int64 a4, unsigned int *a5)
{
  //...
  // 下面这个是秘钥扩展函数,里面有个AES特征向量
  sub_42AE0(key, a4, v17);
  if ( *a5 )
  {
    v18 = 0;
    do
    {
		// ECB模式
      sub_42CBC(key, &v13[v18], v14 + v18, v17);
      v18 += key[3];
    }
    while ( v18 < *a5 );
  }
  operator delete[](v13);
  operator delete[](v17);
  return v14;
}

from Crypto.Cipher import AES
key = [114, 59, 255, 100, 203, 160, 225, 150, 176, 95, 92, 246, 23, 176, 18, 249,]
print(len(key))
aes = AES.new(key=bytes(key),mode=AES.MODE_ECB)

c = bytes([0xB2, 0x82, 0x16, 0xEE, 0x5E, 0xCD, 0x5F, 0xFA, 0xFF,0x82, 0x54, 0xE6, 0xB, 0x4B, 0xAE, 0xAA])
print(aes.decrypt(c))

[rev]notsudoku

在前面要补齐16个字节。。

data = []
with open('2.pyc','rb') as f:
    data = f.read()
struct = []
with open('notsudoku/struct','rb') as f:
    struct = f.read()
with open('2_2.pyc','wb') as f:
    f.write(struct[:16]+data)

穷举脚本，有限时间内我解不出来hhhh

import hashlib
import base64
import sys
import marshal
import dis
import uncompyle6

res = 'e3a912'
flag = [0 for i in range(50)]
state = [[-1 for _ in range(5)] for _ in range(5)]
state[0][1]=24
state[4][3]=2      
state[0][2]=1
state[2][3]=20    
state[1][0]=23
state[3][4]=3
aval = [0 for i in range(25)]
aval[24]=1
aval[2]=1
aval[1]=1
aval[20]=1
aval[23]=1
aval[3]=1
def check(start,state):
    # print(start)
    x = start//5
    y = start%5
    for i in range(x):
        if sum(state[i])!=60:
            return False
    return True

def dfs(state,start,aval):
    x = start//5
    y = start%5
    if start==25:
        isOk=True
        for i in range(5):
            if state[0][i]+state[1][i]+state[2][i]+state[3][i]+state[4][i]!=60:
                isOk=False
                break
        if isOk:
            print(state)
            flag = ''
            dic = [0 for i in range(25)]
            for i in range(5):
                for j in range(5):
                    dic[state[i][j]]=i*5+j
            for i in range(25):
                flag+=hex(dic[i]//5)[2:]
                flag+=hex(dic[i]%5)[2:]
            if hashlib.md5(bytes(flag,encoding='utf-8')).hexdigest()[:6]==res:
                print(flag)
        return
    if state[x][y]!=-1:
        dfs(state,start+1,aval)
    else:
        for i in range(25):
            nstate = [[j for j in state[k]] for k in range(5)]
            nstate[x][y]=i
            naval=[j for j in aval]
            if check(start+1,nstate) and aval[i]==0:
                naval[i]=1
                dfs(nstate,start+1,naval)
dfs(state,0,aval)
s = 0
for i in range(25):
    s+=i+1
print(s,s/5)

#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <math.h>
#include "defs.h"
// #include <setimp.h>
/* POINTER defines a generic pointer type */
typedef unsigned char * POINTER;
 
/* UINT2 defines a two byte word */
//typedef unsigned short int UINT2;
 
/* UINT4 defines a four byte word */
typedef unsigned long int UINT4;
 
 
/* MD5 context. */
typedef struct {
	UINT4 state[4];                                   /* state (ABCD) */
	UINT4 count[2];        /* number of bits, modulo 2^64 (lsb first) */
	unsigned char buffer[64];                         /* input buffer */
} MD5_CTX;
 
void MD5Init (MD5_CTX *context);
void MD5Update (MD5_CTX *context, unsigned char *input, unsigned int inputLen);
void MD5UpdaterString(MD5_CTX *context,const char *string);
int MD5FileUpdateFile (MD5_CTX *context,char *filename);
void MD5Final (unsigned char digest[16], MD5_CTX *context);
void MDString (char *string,unsigned char digest[16]);
int MD5File (char *filename,unsigned char digest[16]);
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21
 
static void MD5_memcpy (POINTER output, POINTER input, unsigned int len);
static void MD5Transform (UINT4 state[4], unsigned char block[64]);
static void Encode (unsigned char *output, UINT4 *input, unsigned int len);
static void MD5_memset (POINTER output, int value, unsigned int len);
static void Decode (UINT4 *output, unsigned char *input, unsigned int len);
 
static unsigned char PADDING[64] = {
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
 
/* F, G, H and I are basic MD5 functions.
*/
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))
 
/* ROTATE_LEFT rotates x left n bits.
*/
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
 
/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
 
/* MD5 initialization. Begins an MD5 operation, writing a new context.
 */
void MD5Init (MD5_CTX *context)                                     /* context */
{
	context->count[0] = context->count[1] = 0;
	/* Load magic initialization constants.
	*/
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;
}
 
/* MD5 block update operation. Continues an MD5 message-digest
  operation, processing another message block, and updating the
  context.
 */
void MD5Update (MD5_CTX *context, unsigned char *input, unsigned int inputLen)
 
{
	unsigned int i, index, partLen;
 
	/* Compute number of bytes mod 64 */
	index = (unsigned int)((context->count[0] >> 3) & 0x3F);
 
	/* Update number of bits */
	if ((context->count[0] += ((UINT4)inputLen << 3))
		< ((UINT4)inputLen << 3))
		context->count[1]++;
	context->count[1] += ((UINT4)inputLen >> 29);
 
	partLen = 64 - index;
 
	/* Transform as many times as possible.
	*/
	if (inputLen >= partLen) {
		MD5_memcpy((POINTER)&context->buffer[index], (POINTER)input, partLen);
		MD5Transform (context->state, context->buffer);
 
		for (i = partLen; i + 63 < inputLen; i += 64)
			MD5Transform (context->state, &input[i]);
 
		index = 0;
	}
	else
		i = 0;
 
	/* Buffer remaining input */
	MD5_memcpy((POINTER)&context->buffer[index], (POINTER)&input[i],inputLen-i);
}
 
/* MD5 finalization. Ends an MD5 message-digest operation, writing the
  the message digest and zeroizing the context.
 */
void MD5Final (unsigned char digest[16], MD5_CTX *context)                                 
{
	unsigned char bits[8];
	unsigned int index, padLen;
 
	/* Save number of bits */
	Encode (bits, context->count, 8);
 
	/* Pad out to 56 mod 64.
	*/
	index = (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	MD5Update (context, PADDING, padLen);
 
	/* Append length (before padding) */
	MD5Update (context, bits, 8);
 
	/* Store state in digest */
	Encode (digest, context->state, 16);
 
	/* Zeroize sensitive information.
	*/
	MD5_memset ((POINTER)context, 0, sizeof (*context));
}
 
/* MD5 basic transformation. Transforms state based on block.
 */
static void MD5Transform (UINT4 state[4], unsigned char block[64])
{
	UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
 
	Decode (x, block, 64);
 
	/* Round 1 */
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
	FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
 
	/* Round 2 */
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
	GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
	GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
	GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
 
	/* Round 3 */
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
 
	/* Round 4 */
	II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
	II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
	II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
	II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
	II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
	II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
	II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
 
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
 
	/* Zeroize sensitive information.
	*/
	MD5_memset ((POINTER)x, 0, sizeof (x));
}
 
/* Encodes input (UINT4) into output (unsigned char). Assumes len is
  a multiple of 4.
 */
static void Encode (unsigned char *output, UINT4 *input, unsigned int len)
{
	unsigned int i, j;
 
	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j] = (unsigned char)(input[i] & 0xff);
		output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
		output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
	}
}
 
/* Decodes input (unsigned char) into output (UINT4). Assumes len is
  a multiple of 4.
 */
static void Decode (UINT4 *output, unsigned char *input, unsigned int len)
{
	unsigned int i, j;
 
	for (i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
		(((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
}
 
/* Note: Replace "for loop" with standard memcpy if possible.
 */
 
static void MD5_memcpy (POINTER output, POINTER input, unsigned int len)
{
	unsigned int i;
 
	for (i = 0; i < len; i++)
		output[i] = input[i];
}
 
/* Note: Replace "for loop" with standard memset if possible.
 */
static void MD5_memset (POINTER output, int value, unsigned int len)
{
	unsigned int i;
 
	for (i = 0; i < len; i++)
		((char *)output)[i] = (char)value;
}
/* Digests a string and prints the result.
 */
void MDString (char *string,unsigned char digest[16])
{
	MD5_CTX context;
	unsigned int len = strlen (string);
 
	MD5Init (&context);
	MD5Update (&context, (unsigned char *)string, len);
	MD5Final (digest, &context);
}
/* Digests a file and prints the result.
 */
int MD5File (char *filename,unsigned char digest[16])
{
	FILE *file;
	MD5_CTX context;
	int len;
	unsigned char buffer[1024];
 
	if ((file = fopen (filename, "rb")) == NULL)
		return -1;
	else {
		MD5Init (&context);
		while (len = fread (buffer, 1, 1024, file))
			MD5Update (&context, buffer, len);
		MD5Final (digest, &context);
 
		fclose (file);
	}
	return 0;
}
void MD5UpdaterString(MD5_CTX *context,const char *string)
{
	unsigned int len = strlen (string);
	MD5Update (context, (unsigned char *)string, len);
}
int MD5FileUpdateFile (MD5_CTX *context,char *filename)
{
	FILE *file;
	int len;
	unsigned char buffer[1024];
 
	if ((file = fopen (filename, "rb")) == NULL)
		return -1;
	else {
		while (len = fread (buffer, 1, 1024, file))
			MD5Update (context, buffer, len);
		fclose (file);
	}
	return 0;
}
uint16_t wa[] = {48885, 35772, 41193, 29456, 55568, 41901, 52406, 19934, 13388, 15318, 26385, 34447, 7290, 33829, 27405, 6988};
int32_t d_40212c[]={-1,0,0,0,1};
int32_t d_402140[]={0,0,-1,1,0};
void printArray(const char *name,uint8_t *v,size_t len) 
{
    printf("========%s=========\n",name);
    for(size_t i=0;i<len;i++){
        printf("0x%02X,",v[i]);
    }
    printf("\n=================\n");
}
uint8_t check(uint8_t *state,uint8_t start){
    uint32_t sum=0;
    uint32_t x=start/5;
    uint32_t y=start%5;

    for(int i=0;i<x;i++){
        sum=0;
        for(int j=0;j<5;j++){
            sum+=state[i*5+j];
        }
        if(sum-60!=0)return 0;
    }
    return 1;
}
uint8_t flag[51];
uint8_t tab[25];
void dfs(uint8_t *state,uint8_t start,uint8_t *aval){
    // printf("%d\n",start);
    if(start==25){
        uint8_t isOk=1;
        for(int i=0;i<5;i++){
            uint32_t sum=0;
            for(int j=0;j<5;j++){
                sum+=state[j*5+i];
            }
            if(sum-60!=0){
                isOk=0;
            }
        }
        if(isOk){
            // printArray("ok state",state,25);
            for(int i=0;i<25;i++){
                tab[state[i]]=i;
            }
            for(size_t i=0;i<50;i+=2){
                flag[i]=tab[i]/5+'0';
                flag[i+1]=tab[i]%5+'0';
            }
            MD5_CTX md5c;
            MD5Init(&md5c);
            MD5UpdaterString(&md5c,flag);
            uint8_t digest[16];
            MD5Final(digest,&md5c);
            uint8_t cmpData[]={0xe3,0xa9,0x12};
            if(!memcmp(cmpData,digest,3)){
                printf("%s\n",flag);
                exit(0);
            }
        }
        return;
    }
    if(state[start]-0xff!=0){
        dfs(state,start+1,aval);
    }else{
        // uint8_t *naval=alloca(25);
        // uint8_t *nstate=alloca(25);
        for(uint8_t i=0;i<25;i++){
            if(aval[i]==0){
            //     memcpy(naval,aval,25);
            //     memcpy(nstate,state,25);
                state[start]=i;
                aval[i]=1;
                // printf("%d\n",start);
                if(check(state,start+1))
                    dfs(state,start+1,aval);
                state[start]=-1;
                aval[i]=0;
            }
        }
    }
}
int main(){
    memset(flag,0,51);
    uint8_t aval[25];
    uint8_t state[25];
    memset(state,-1,25);
    memset(aval,0,25);
    state[1]=24;
    state[4*5+3]=2;      
    state[2]=1;
    state[2*5+3]=20;    
    state[1*5+0]=23;
    state[3*5+4]=3;
    aval[24]=1;
    aval[2]=1;
    aval[1]=1;
    aval[20]=1;
    aval[23]=1;
    aval[3]=1;
    dfs(state,0,aval);
    return 0;
}