不得不说，我的思维水平一直在低位徘徊，技术水平仍然停留在以前。

就像有家公司，你去面试，他说他对一个人说的话的根本就不感兴趣，他想看看你写的东西，比如博客。我后来才感觉，他是对的，从一个人的字里行间就可以知道他是什么人，他的思维模式，他经历的历史。

大约在2016年，我经历了第一次android逆向的完整过程，非常感谢当时老板的支持，因为我们那时候没人懂这个玩意儿，但是老板的奇思妙想和支持，同事的信任，自己的任性，都为我提供了很多的勇气和毅力来完成这个项目。那时候我一直坚信，我可以重构整个internet，只要我想的话。这种执着给我提供了源源不断的动力，就像在前线、在战场，意志力为一个战士的舞台提供了无与伦比的想象空间。

该程序是一个同步程序，用于备份同步本机和服务器上的通讯录、短信、通话记录等信息。其网络数据全部加密，其解密后核心算法如下：

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#include "stdafx.h"   unsigned char TeaKey[256] = {0};   unsigned char unk_19578[] = { 0x44,0x46,0x47,0x00,0x00,0x00,0x00,0x3C,0x3E,0x3C,0x00,0x00,0x00,0x00,0x26,0x2A, 0x4D,0x00,0x00,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x02,0x00,0x06,0x00,0x03,0x00, 0x05,0x00,0x04,0x00,0x00 };   unsigned char  * unk_1957F = unk_19578 + 7; unsigned char * unk_19586 = unk_19578 + 14; unsigned char  * unk_1958E = unk_19578 + 22;   unsigned char unk_1A43C[] = { 0x78,0xA4,0x6A,0xD7,0x56,0xB7,0xC7,0xE8,0xDB,0x70,0x20,0x24,0xEE,0xCE,0xBD,0xC1, 0xAF,0x0F,0x7C,0xF5,0x2A,0xC6,0x87,0x47,0x13,0x46,0x30,0xA8,0x01,0x95,0x46,0xFD, 0xD8,0x98,0x80,0x69,0xAF,0xF7,0x44,0x8B,0xB1,0x5B,0xFF,0xFF,0xBE,0xD7,0x5C,0x89, 0x22,0x11,0x90,0x6B,0x93,0x71,0x98,0xFD,0x8E,0x43,0x79,0xA6,0x21,0x08,0xB4,0x49, //1a47c 0x62,0x25,0x1e,0xf6,0x40,0xB3,0x40,0xC0,0x51,0x5A,0x5E,0x26,0xAA,0xC7,0xB6,0xE9, 0x5D,0x10,0x2F,0xD6,0x53,0x14,0x44,0x02,0x81,0xE6,0xA1,0xD8,0xC8,0xFB,0xD3,0xE7, 0xE6,0xCD,0xE1,0x21,0xD6,0x07,0x37,0xC3,0x87,0x0D,0xD5,0xF4,0xED,0x14,0x5A,0x45, 0x05,0xE9,0xE3,0xA9,0xF8,0xA3,0xEF,0xFC,0xD9,0x02,0x6F,0x67,0x8A,0x4C,0x2A,0x8D, 0x42,0x39,0xFA,0xFF,0x81,0xF6,0x71,0x87,0x22,0x61,0x9D,0x6D,0x0C,0x38,0xE5,0xFD, 0x44,0xEA,0xBE,0xA4,0xA9,0xCF,0xDE,0x4B,0x60,0x4B,0xBB,0xF6,0x70,0xBC,0xBF,0xBE, 0xC6,0x7E,0x9B,0x28,0xFA,0x27,0xA1,0xEA,0x85,0x30,0xEF,0xD4,0x05,0x1D,0x88,0x04, 0x39,0xD0,0xD4,0xD9,0xE5,0x99,0xDB,0xE6,0xF8,0x7C,0xA2,0x1F,0x65,0x56,0xAC,0xC4, 0x44,0x22,0x29,0xF4,0x97,0xFF,0x2A,0x43,0xA7,0x23,0x94,0xAB,0x39,0xA0,0x93,0xFC, 0xC3,0x59,0x5B,0x65,0x92,0xCC,0x0C,0x8F,0x7D,0xF4,0xEF,0xFF,0xD1,0x5D,0x84,0x85, 0x4F,0x7E,0xA8,0x6F,0xE0,0xE6,0x2C,0xFE,0x14,0x43,0x01,0xA3,0xA1,0x11,0x08,0x4E, 0x82,0x7E,0x53,0xF7,0x35,0xF2,0x3A,0xBD,0xBB,0xD2,0xD7,0x2A,0x91,0xD3,0x86,0xEB, //1a53c 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F, 0x01,0x06,0x0B,0x00,0x05,0x0A,0x0F,0x04,0x09,0x0E,0x03,0x08,0x0D,0x02,0x07,0x0C, 0x05,0x08,0x0B,0x0E,0x01,0x04,0x07,0x0A,0x0D,0x00,0x03,0x06,0x09,0x0C,0x0F,0x02, 0x00,0x07,0x0E,0x05,0x0C,0x03,0x0A,0x01,0x08,0x0F,0x06,0x0D,0x04,0x0B,0x02,0x09, //1a57c 0x07,0x0C,0x11,0x16,0x05,0x09,0x0E,0x14,0x04,0x0B,0x10,0x17,0x06,0x0A,0x0F,0x15, 0x98,0x2F,0x8A,0x42,0x91,0x44,0x37,0x71,0xCF,0xFB,0xC0,0xB5,0xA5,0xDB,0xB5,0xE9, 0x5B,0xC2,0x56,0x39,0xF1,0x11,0xF1,0x59,0xA4,0x82,0x3F,0x92,0xD5,0x5E,0x1C,0xAB, 0x98,0xAA,0x07,0xD8,0x01,0x5B,0x83,0x12,0xBE,0x85,0x31,0x24,0xC3,0x7D,0x0C,0x55, 0x74,0x5D,0xBE,0x72,0xFE,0xB1,0xDE,0x80,0xA7,0x06,0xDC,0x9B,0x74,0xF1,0x9B,0xC1, 0xC1,0x69,0x9B,0xE4,0x86,0x47,0xBE,0xEF,0xC6,0x9D,0xC1,0x0F,0xCC,0xA1,0x0C,0x24, 0x6F,0x2C,0xE9,0x2D,0xAA,0x84,0x74,0x4A,0xDC,0xA9,0xB0,0x5C,0xDA,0x88,0xF9,0x76, 0x52,0x51,0x3E,0x98,0x6D,0xC6,0x31,0xA8,0xC8,0x27,0x03,0xB0,0xC7,0x7F,0x59,0xBF, 0xF3,0x0B,0xE0,0xC6,0x47,0x91,0xA7,0xD5,0x51,0x63,0xCA,0x06,0x67,0x29,0x29,0x14, 0x85,0x0A,0xB7,0x27,0x38,0x21,0x1B,0x2E,0xFC,0x6D,0x2C,0x4D,0x13,0x0D,0x38,0x53, 0x54,0x73,0x0A,0x65,0xBB,0x0A,0x6A,0x76,0x2E,0xC9,0xC2,0x81,0x85,0x2C,0x72,0x92, 0xA1,0xE8,0xBF,0xA2,0x4B,0x66,0x1A,0xA8,0x70,0x8B,0x4B,0xC2,0xA3,0x51,0x6C,0xC7,   0x19,0xE8,0x92,0xD1,0x24,0x06,0x99,0xD6,0x85,0x35,0x0E,0xF4,0x70,0xA0,0x6A,0x10, 0x16,0xC1,0xA4,0x19,0x08,0x6C,0x37,0x1E,0x4C,0x77,0x48,0x27,0xB5,0xBC,0xB0,0x34, 0xB3,0x0C,0x1C,0x39,0x4A,0xAA,0xD8,0x4E,0x4F,0xCA,0x9C,0x5B,0xF3,0x6F,0x2E,0x68, 0xEE,0x82,0x8F,0x74,0x6F,0x63,0xA5,0x78,0x14,0x78,0xC8,0x84,0x08,0x02,0xC7,0x8C, 0xFA,0xFF,0xBE,0x90,0xEB,0x6C,0x50,0xA4,0xF7,0xA3,0xF9,0xBE,0xF2,0x78,0x71,0xC6};   unsigned char * unk_1A47C = unk_1A43C + 0x40; unsigned char *  unk_1A53C = unk_1A43C + 0x100; unsigned char *  unk_1A57C = unk_1A43C + 0x140;     int __fastcall sub_144C8(int result, unsigned int a2)        //52,packet size/4 {   char v2  = 0; // nf@0   int v3; // r12@1   int v4; // r3@4   char v5; // r0@8   unsigned int v6; // r1@8   unsigned int v7; // r2@8   bool v8; // zf@17     v3 = result ^ a2;     if ( a2 <= 0 )     a2 = -a2;     if ( a2 == 1 )   {     if ( (v3 ^ result) < 0 )       result = -result;     return result;   }   else   {     v4 = result;     if ( result < 0 )       v4 = -result;       if ( v4 <= a2 )     {       if ( v4 < a2 )         result = 0;            if ( v4 == a2 )         result = (v3 >> 31) | 1;     }     else if ( a2 & (a2 - 1) )     {       //v5 = __clz(a2) - __clz(v4);       __asm       {           pushad           mov eax,a2           bsr ecx,eax           mov edx,32           sub edx,ecx           sub edx,1           mov ebx,edx             mov eax,v4           bsr ecx,eax           mov edx,32           sub edx,ecx           sub edx,1             sub ebx,edx           mov v5,bl           popad       }         v6 = a2 << v5;       v7 = 1 << v5;       result = 0;       while ( 1 )       {         if ( v4 >= v6 )         {           v4 -= v6;           result |= v7;         }         if ( v4 >= v6 >> 1 )         {           v4 -= v6 >> 1;           result |= v7 >> 1;         }         if ( v4 >= v6 >> 2 )         {           v4 -= v6 >> 2;           result |= v7 >> 2;         }         if ( v4 >= v6 >> 3 )         {           v4 -= v6 >> 3;           result |= v7 >> 3;         }         v8 = v4 == 0;         if ( v4 )         {           v7 >>= 4;           v8 = v7 == 0;         }         if ( v8 )           break;         v6 >>= 4;       }       if ( v3 < 0 )         result = -result;     }     else     {         int Tmp = 0;         __asm         {             pushad             mov eax,a2             bsr ecx,eax             mov edx,32             sub edx,ecx             sub edx,1             mov Tmp,edx             popad       }         result = (unsigned int)v4 >> (31 - Tmp);       //result = (unsigned int)v4 >> (31 - __clz(a2));         if ( result < 0 )         result = -result;     }   }   return result; }             int __fastcall sub_144C0(int a1, int a2)            // 52, packet size {     if ( !a2 )         return 0;         //JUMPOUT(&loc_152A0);     return sub_144C8(a1, a2); }               int __fastcall sub_B764(unsigned int a1, unsigned int a2, int a3)            //a1 = key  a2 = 64, a3 = int [] return by c160 {     int v3; // r4@1     int v4; // r5@1     int v5; // r3@1     int v6; // r6@1     int v7; // r3@1     int v8; // r1@4     unsigned int v9; // r2@4     int v10; // r4@4     int *v11; // r3@4     int v12; // r2@5     int v13; // r0@5     int v14; // r1@5     int v15; // r6@5     int v16; // r3@5     int v17; // r4@7     int v18; // r4@8     int v19; // r6@8     int v20; // r3@8     int v21; // r2@10     char v22; // r6@10     int v23; // r2@10     int v24; // r2@10   int v25; // r3@11   int v26; // r5@11   int v27; // r0@13   int v28; // r5@13   int v29; // r0@13   int v30; // r3@14   int v31; // r5@14   int v32; // r1@16   int v33; // r5@16   int v34; // r1@16   int result; // r0@18   int v36; // r2@20   int v37; // r1@20   int v38; // r3@20   int v39; // r4@20     int v41; // [sp+4h] [bp+4h]@5   int v42; // [sp+8h] [bp+8h]@3   int v43; // [sp+Ch] [bp+Ch]@3   int v44; // [sp+10h] [bp+10h]@1   int v45; // [sp+14h] [bp+14h]@11   int v46; // [sp+18h] [bp+18h]@3   int v47; // [sp+1Ch] [bp+1Ch]@1   int v48; // [sp+20h] [bp+20h]@1   int v49; // [sp+24h] [bp+24h]@1   int v50; // [sp+28h] [bp+28h]@1   unsigned int v51; // [sp+2Ch] [bp+2Ch]@3   int v52; // [sp+30h] [bp+30h]@7   int v53; // [sp+34h] [bp+34h]@3   int v54[17]; // [sp+38h] [bp+38h]@19            //////////////////////////////////////////////////////////////////////////       v44 = a1 + 4 * (a2 >> 2);   v3 = *(_DWORD *)(a3 + 4);   v4 = *(_DWORD *)(a3 + 8);   v50 = *(_DWORD *)a3;   v5 = *(_DWORD *)(a3 + 16);   v6 = *(_DWORD *)(a3 + 12);   v49 = v3;   v7 = a2 + v5;   v48 = v4;   v47 = v6;   *(_DWORD *)(a3 + 16) = v7;   if ( v7 < a2 )     ++*(_DWORD *)(a3 + 20);   v51 = a1;   v46 = (int)unk_1A53C;        //////////////////////////////////////////////////////////////////////////   v53 = (int)&v54[16];        //////////////////////////////////////////////////////////////////////////   v43 = (int)unk_1A57C;        //////////////////////////////////////////////////////////////////////////   v42 = a3;     int  Tmp = (int)v54;     while ( 1 )   {     result = v44;     if ( v51 >= v44 )       break;     v9 = v51;     v11 = v54;     do     {       v8 = *(_DWORD *)v9;       v9 += 4;       v10 = v53;       *v11 = v8;       ++v11;            //将16字节数据和接下来的原始密钥拷贝到此处     }     while ( v11 != (int *)v10 );     v12 = v47;     v51 += 64;     v13 = v48;     v14 = v49;     v15 = v50;     v16 = 0;     v41 = (int)unk_1A53C;     while ( 1 )     {         v52 = (v12 ^ v13) & v14 ^ v12;            //顺序正确       v52 += *((_DWORD *)unk_1A43C + v16) + v15 + *(DWORD*)((DWORD*)Tmp + *(_BYTE *)(v16 + v41) );            //////////////////////////////////////////////       v17 = __ROR4__(v52, 32 - *(_BYTE *)(v41 + 64 + (v16++ & 3)));       if ( v16 == 16 )         break;       v15 = v12;       v12 = v13;       v13 = v14;       v14 += v17;     }     v18 = v17 + v14;     v19 = v12;     v20 = 0;     while ( 1 )     {       v21 = ((v14 ^ v18) & v13 ^ v14)           + v19           + *((_DWORD *)unk_1A43C + v20 + 16)           + *(DWORD*)((DWORD*)Tmp + *(_BYTE *)(v46 + v20 + 16));       v22 = *(_BYTE *)(v43 + (v20++ & 3) + 4);       v23 = __ROR4__(v21, 32 - v22);       v24 = v23 + v18;       if ( v20 == 16 )         break;       v19 = v13;       v13 = v14;       v14 = v18;       v18 = v24;     }     v45 = (int)unk_1A57C;     v25 = 0;     v26 = v13;     while ( 1 )     {       v27 = (v18 ^ v24 ^ v14) + v26 + *((_DWORD *)unk_1A43C + v25 + 32);       v52 = v27;       v52 = v27 + *(DWORD*)((DWORD*)Tmp + *((_BYTE *)unk_1A53C + v25 + 32) );       v27 = (v27 & 0xffffff00) + *(_BYTE *)(v45 + (v25++ & 3) + 8);       v28 = __ROR4__(v52, 32 - v27);       v29 = v28 + v24;       if ( v25 == 16 )         break;       v26 = v14;       v14 = v18;       v18 = v24;       v24 = v29;     }     v45 = (int)unk_1A57C;     v30 = 0;     v31 = v14;     while ( 1 )     {       v32 = ((~v18 | v29) ^ v24) + v31 + *((_DWORD *)unk_1A43C + v30 + 48);       v52 = v32;       v52 = v32 + *(DWORD*)((DWORD*)Tmp + *((_BYTE *)unk_1A53C + v30 + 48) );       v32 = (v32 & 0xffffff00) + *(_BYTE *)(v45 + (v30++ & 3) + 12);       v33 = __ROR4__(v52, 32 - v32);       v34 = v33 + v29;       if ( v30 == 16 )         break;       v31 = v18;       v18 = v24;       v24 = v29;       v29 = v34;     }     v50 += v18;     v49 += v34;     v48 += v29;     v47 += v24;   }     //////////////////////////////////////////////////////////////////////////   v36 = v42;   v37 = v50;   v38 = v49;   v39 = v48;   *(_DWORD *)(v42 + 12) = v47;   *(_DWORD *)v36 = v37;   *(_DWORD *)(v36 + 4) = v38;   *(_DWORD *)(v36 + 8) = v39;   return result; }                         int __fastcall sub_C160(int result) {   *(_DWORD *)result = 1732584193;   *(_DWORD *)(result + 4) = -271733879;   *(_DWORD *)(result + 8) = -1732584194;   *(_DWORD *)(result + 12) = 271733878;   *(_DWORD *)(result + 20) = 0;   *(_DWORD *)(result + 16) = 0;   *(_DWORD *)(result + 24) = 0;     //C190拷贝原始密钥到后面的字节中   return result; }         //将原始密钥传入C160返回的数组中的第28开始的字节中 void *__fastcall sub_C190(void *result, int a2, unsigned int a3)    //int[] return by c160 ,key,keylen {   int v3; // r6@1   int v4; // r5@3   int v5; // r5@6   unsigned int v6; // r4@7   int v7; // r5@7   unsigned int v8; // [sp+4h] [bp+4h]@1   const void *src; // [sp+8h] [bp+8h]@1   int n; // [sp+Ch] [bp+Ch]@1   int na; // [sp+Ch] [bp+Ch]@4     v3 = (int)result;   src = (const void *)a2;   v8 = a3;   n = a3;   if ( a3 << 26 )   {     v4 = *((_DWORD *)result + 6);     if ( v4 )     {       na = a3;       if ( a3 > 128 - v4 )         na = 128 - v4;       result = memcpy((char *)result + v4 + 28, (const void *)a2, na);       v5 = na + v4;       *(_DWORD *)(v3 + 24) += na;       if ( (unsigned int)v5 > 0x40 )       {         v6 = v3 + (v5 & 0xFFFFFFC0);         sub_B764(v3 + 28, v5 & 0xFFFFFFC0, v3);         v7 = v5 & 0x3F;         result = memcpy((void *)(v3 + 28), (const void *)(v6 + 28), v7);         *(_DWORD *)(v3 + 24) = v7;       }       src = (char *)src + na;       n = v8 - na;     }     if ( n > 64 )     {       result = (void *)sub_B764((unsigned int)src, n & 0xFFFFFFC0, v3);       src = (char *)src + (n & 0xFFFFFFC0);       n &= 0x3Fu;     }     if ( n > 0 )     {       result = memcpy((void *)(v3 + 28), src, n);       *(_DWORD *)(v3 + 24) = n;     }   }   else   {     result = (void *)sub_B764(a2, a3, (int)result);   }   return result; }         //低位是C160 C190制造的密钥，高位指向一个整数 a2是一个整数 __int64 __fastcall sub_C250(__int64 a1, int a2)        //完成密钥的生成和复制，参数为两个地址 {   int _8; // ST08_4@1   unsigned int v3; // r5@1   int v4; // r4@1   int v5; // r3@1   int v6; // r6@1   signed int v7; // r3@3   int v8; // r5@5   int v9; // r3@5   __int64 _0; // [sp+0h] [bp+0h]@1     _0 = a1;   _8 = a2;   v3 = *(_DWORD *)(a1 + 24);        //原始密钥长度21//   v4 = a1;   v5 = v3 + *(_DWORD *)(a1 + 16);    //21   v6 = HIDWORD(a1);                    //数组   *(_DWORD *)(a1 + 16) = v5;        //0   if ( v5 < v3 )     ++*(_DWORD *)(a1 + 20);   v7 = 120;   if ( v3 <= 0x37 )     v7 = 56;   HIDWORD(_0) = v7 - v3;                //35   memset((void *)(a1 + v3 + 28), 0, v7 - v3);   *(_BYTE *)(v4 + v3 + 28) = -128;   v8 = HIDWORD(_0) + v3;   v9 = v4 + v8;   *(_DWORD *)(v9 + 28) = 8 * *(_DWORD *)(v4 + 16);   *(_DWORD *)(v9 + 32) = *(_QWORD *)(v4 + 16) >> 29;   sub_B764(v4 + 28, v8 + 8, v4);   *(_DWORD *)v6 = *(_DWORD *)v4;                            //返回真实的密钥 key, 64 ,16 bytes params   *(_DWORD *)(v6 + 4) = *(_DWORD *)(v4 + 4);   *(_DWORD *)(v6 + 8) = *(_DWORD *)(v4 + 8);   *(_DWORD *)(v6 + 12) = *(_DWORD *)(v4 + 12);   return _0; }           int __fastcall sub_C2C4(const void *a1, unsigned int a2, void *a3)        //a1== key, a2 == keylen, a3 == int[] {   void *v3; // r6@1   unsigned int v4; // r5@1   int result; // r0@1   unsigned __int64 v6; // r2@1   __int64 v7; // r0@3   void * v8 = a3; // r2@3            //V8初始化为A3   const void *src; // [sp+4h] [bp+4h]@1   int v10[0x100]; // [sp+8h] [bp+8h]@3                                        //////////////////////////////////////////////////////////////////////////       v3 = a3;   src = a1;   v4 = a2;   //v11 = _stack_chk_guard;   result = (int)memset(a3, 0, 0x10);   v6 = __PAIR__((unsigned int)src, (unsigned int)src) - __PAIR__((unsigned int)((char *)src - 1), 1);    //此处编译有问题   if ( (signed int)v4 > 16 && HIDWORD(v6) )   {     sub_C160((int)v10);                //////////////////////////////////////////////////////////////////////////     sub_C190(v10, (int)src, v4);    //////////////////////////////////////////////////////////////////////////     LODWORD(v7) = (unsigned int)v10;     HIDWORD(v7) = (unsigned int)v3;     result = sub_C250(v7, (int)v8);            //低位是C160 C190制造的密钥，根据汇编V8指向a3   }   else if ( (signed int)v4 > 0 && HIDWORD(v6) )   {     result = (int)memcpy(v3, src, v4);   } //   if ( v11 != _stack_chk_guard ) //     _stack_chk_fail(result);   return result; } // 14FC: using guessed type int __fastcall _stack_chk_fail(_DWORD);                       unsigned int __fastcall sub_C340(void *src, size_t n, int a3, int a4, void *dest, int a6) {   unsigned int v6; // r6@11   int v7; // r4@8   unsigned int v8; // r3@9   unsigned int v9; // r12@9   char *v10; // r2@10   int v11; // r0@11   int v12; // r4@11   int v13; // r6@11   int v14; // r1@12   signed int v15; // r3@15   int v16; // r4@16   bool v17; // cf@16   unsigned int v19; // [sp+0h] [bp+0h]@11   int v20; // [sp+4h] [bp+4h]@9   unsigned int v21; // [sp+8h] [bp+8h]@11   char *v22; // [sp+Ch] [bp+Ch]@9   unsigned int v23; // [sp+10h] [bp+10h]@10   int v24; // [sp+14h] [bp+14h]@9   int v25; // [sp+18h] [bp+18h]@1   int v26; // [sp+1Ch] [bp+1Ch]@12     int v27[0x100] = {0}; // [sp+20h] [bp+20h]@8            //此处应该是个数组       //v19 = (int)(v27-8);     //memmove((char*)v35,"\xf1\x5e\x78\xd2\x30\x33\xc2\xc4\xba\xc8\xa0\x25\x67\x7e\x86\x3a",16);   v6 = n;   v26 = a3;   v25 = a4;   if ( (signed int)n <= 0 || !src )     return 0;   if ( n << 30 )            //长度为4的倍数     return -32227;   if ( !dest )     return v6;   if ( a6 < (signed int)n )     return -32227;   if ( dest != src )                            //这里肯定相等     memcpy(dest, src, n);   sub_C2C4((const void *)v26, v25, v27);        //v27 is int[]   v26 = v6 >> 2;   v25 = (v6 >> 2) - 1;   v7 = *(_DWORD *)dest;   if ( v25 <= 0 )   {     v15 = 3;     do     {       v16 = __ROR4__(v7 - (*((int*)v27 + v15) ^ 0x9E3779B9), 16);       v7 = v16 ^ 0x79B99E37;       v17 = (unsigned int)v15-- >= 1;     }     while ( v17 );     *(_DWORD *)dest = v7;   }   else   {     v24 = sub_144C0(52, v26);     v8 = -1640531527 * (v24 + 6);     v9 = v6;     v22 = (char *)dest + 4 * v25;     v20 = 4 * (v26 + 0x3FFFFFFF);     while ( v24 != -6 )     {       v23 = (v8 >> 2) & 3;       v10 = (char *)dest + v20;       v26 = v25;       do       {         v21 = (*(v27 + (v26 & 3 ^ v23) ) ^ *((_DWORD *)v10 - 1)) + (v7 ^ v8);         v19 = ((unsigned int)v7 >> 3) ^ 16 * *((_DWORD *)v10 - 1);         v11 = (v19 + (4 * v7 ^ (*((_DWORD *)v10 - 1) >> 5))) ^ v21;         v12 = *(_DWORD *)v10;         --v26;         v13 = v26;         v7 = v12 - v11;         *(_DWORD *)v10 = v7;         v10 -= 4;       }       while ( v13 );       v7 = *(_DWORD *)dest          - (((16 * *(_DWORD *)v22 ^ ((unsigned int)v7 >> 3)) + ((*(_DWORD *)v22 >> 5) ^ 4 * v7)) ^ ((v7 ^ v8)                                                                                                   + (*(_DWORD *)v22 ^ *(v27 + v23))));       v14 = v24 - 1;       *(_DWORD *)dest = v7;       v8 += 1640531527;       v24 = v14;     }     v6 = v9;   }     return v6; }         unsigned int __fastcall sub_C49C(void *a1, int a2, int a3, int a4, void *a5, int a6)        {   unsigned int result; // r0@1   int v7; // r3@3     result = sub_C340(a1, a2, a3, a4, a5, a6);   if ( (signed int)result > 0 && a5 )   {     v7 = *(_DWORD *)((char *)a5 + result - 4);     if ( v7 < 0 || (signed int)(result - 3) <= v7 )     {       result = -32227;     }     else     {       *((_BYTE *)a5 + v7) = 0;       result = v7;     }   }   return result; }                         //src == dest == packet, a2== a6 == pack len, a3 = key, a4 = keylen int __fastcall sub_C4D8(void *src, int a2, int a3, int a4, void *dest, int a6)    {   int v6; // r5@3   size_t i; // r2@8   unsigned int v8; // r3@11   char *v9; // r6@11   unsigned int v10; // r5@11   unsigned int v11; // r3@12   void *v12; // r1@13   unsigned int v13; // r3@13   int v14; // r2@13   unsigned int v15; // r12@13   int v16; // r0@14   int v17; // r3@14   int v18; // r3@14   unsigned int v19; // r0@14   int v20; // r0@14   unsigned int v21; // r2@15   int v22; // r1@15   int *v23; // r2@18   int v24; // r6@19   int v25; // r3@19     unsigned int v28; // [sp+4h] [bp+4h]@14   size_t v29; // [sp+8h] [bp+8h]@12   unsigned int v30; // [sp+Ch] [bp+Ch]@14   unsigned int v31; // [sp+10h] [bp+10h]@13   int v32; // [sp+14h] [bp+14h]@1   size_t v33; // [sp+18h] [bp+18h]@1   size_t n; // [sp+1Ch] [bp+1Ch]@1   int v35[0x10] = {0}; // [sp+20h] [bp+20h]@11         //memmove((char*)v35,"\xf1\x5e\x78\xd2\x30\x33\xc2\xc4\xba\xc8\xa0\x25\x67\x7e\x86\x3a",16);   n = a2;   v33 = a3;   v32 = a4;   if ( a2 > 0 && src )   {     v6 = (a2 + 3) & 0xFFFFFFFC;     if ( dest )     {       if ( a6 >= v6 )       {         if ( dest != src )           memcpy(dest, src, n);         for ( i = n; (signed int)i < v6; ++i )           *((_BYTE *)dest + i) = 0;         n = i;         sub_C2C4((const void *)v33, v32, v35);         v8 = *(_DWORD *)dest;         v9 = (char *)dest + 4 * ((n >> 2) - 1);         v33 = (n >> 2) - 1;         v10 = *(_DWORD *)v9;         if ( (signed int)v33 <= 0 )         {           v23 = v35;           do           {             v24 = *v23;             ++v23;             v25 = __ROR4__(v8, 16);             v8 = (v24 ^ 0x9E3779B9) + (v25 ^ 0x9E3779B9);           }           while ( v23 != &v35[4] );           *(_DWORD *)dest = v8;         }         else         {           v32 = sub_144C0(52, n >> 2);           v11 = 0;           v29 = v33 & 3;           while ( v32 != -6 )           {             v12 = dest;             v13 = v11 - 1640531527;        //0xffffffff9E3779B9             v31 = (v13 >> 2) & 3;             v14 = 0;             v15 = v13;             do             {                 //v27 = 0;               v16 = *(DWORD*)(v35 + (v14 & 3 ^ v31) );               v17 = *(_DWORD *)((_DWORD *)v12 + 1);               ++v14;               v30 = v16 ^ v10;               v18 = (v16 ^ v10) + (v17 ^ v15);               v19 = *((_DWORD *)v12 + 1);               v30 = v18;               v28 = 16 * v10 ^ (v19 >> 3);               v10 = ((v28 + ((v10 >> 5) ^ 4 * v19)) ^ v18) + *(_DWORD *)v12;               v20 = v33;               *(_DWORD *)v12 = v10;               v12 = (char *)v12 + 4;             }             while ( v14 < v20 );             v21 = *(_DWORD *)dest;             v11 = v15;             v30 = (*(_DWORD *)dest >> 3) ^ 16 * v10;             v10 = ((v30 + (4 * v21 ^ (v10 >> 5))) ^ ((v10 ^ *(v35 + (v31 ^ v29) )) + (v21 ^ v15))) + *(_DWORD *)v9;             v22 = v32;             *(_DWORD *)v9 = v10;             v32 = v22 - 1;           }         }           v6 = n;       }       else       {         v6 = -32226;       } //      Utf8ToGB2312((char*)dest,v6);     }   }   else   {     v6 = 0;   }   return v6; }         int __fastcall sub_C62C(void *src, int a2, int a3, int a4, void *dest, int a6) {   int v6; // r6@1   int v7; // r5@1   int i; // r1@5   int v10; // [sp+8h] [bp+0h]@1   int v11; // [sp+Ch] [bp+4h]@1     v10 = a4;   v6 = a2;   v11 = a3;   v7 = ((a2 + 3) & 0xFFFFFFFC) + 4;   if ( dest )   {     if ( a6 < v7 )     {       v7 = -1;     }     else     {       if ( dest != src )         memcpy(dest, src, a2);       for ( i = v6; i < v7; ++i )         *((_BYTE *)dest + i) = 0;       *((_DWORD *)dest + (i >> 2) - 1) = v6;       v7 = sub_C4D8(dest, i, v11, v10, dest, i);     }   }   return v7; }         int  __fastcall sub_183C(char * str,int strlen,char * key, int keylen, char * decbuf, int decbuflen,int Flag) {       int Cnt = 0;     if ( Flag )         Cnt = sub_C62C(str, strlen, (int)key, keylen, decbuf, decbuflen);     else         Cnt = sub_C49C(str, strlen, (int)key, keylen, decbuf, decbuflen);       if (Cnt <= 0)     {         return 0;     }       return Cnt; }                 // void __cdecl New_sub_16f4() // { //     __asm //     { //         //push edi //         //push esi //         //push ebx //         push ebp //         mov ebp,esp //         sub esp,0x7c //         //         push 64 //         push 0 //         push offset TeaKey //         call memset //         add esp ,12 // //         push dword ptr 0x7c //         push dword ptr 0 //         push esp //         call memset //         add esp,12 //         add esp,0x20 // //         mov ebx, esp //         add ebx ,8 //         //         push 4 //         push offset unk_19578 //         mov eax, ebx //         add eax,0x1f //         push eax //         call memcpy //         add esp,12 // // //         mov eax,0x252423 //         mov [ebx + 0x54 - 0x3c], eax            //         mov eax, offset unk_19578 //         mov [ebx + 0x54 - 0x50],eax        //         mov ax,0x235e //         mov [ebx + 0x54 - 0x2e],ax            //         mov ax,0x25 //         mov [ebx + 0x54 - 0x2c],ax        // //         push 4 //         mov eax,offset unk_19578 //         add eax, 7 //         push eax //         mov eax,ebx //         add eax,0x2d //         push eax //         call memcpy //         add esp,12 // //         mov eax,0x475224 //         mov [ebx + 0x54 - 0x20],eax // //         push 4 //         mov eax,offset unk_19578 //         add eax,0x0e //         push eax //         mov eax,ebx //         add eax,0x3b //         push eax //         call memcpy //         add esp,12 // // //         mov ax,0x5248 //         mov [ebx + 0x42],ax //         mov ax,0x28 //         mov [ebx + 0x42 + 2],ax // //         push 0x0e //         mov eax,offset unk_19578 //         add eax, 0x16 //         push eax //         mov eax,ebx //         add eax,8 //         push eax //         call memcpy //         add esp,12 // //         sub esp,0x20 //         //push 0x20 //         //push 0 //         //push esp //         //call memset //         //add esp,12 // //         mov esi,esp //         add esi,8 // //         lea esi,TeaKey //         //         push esi // //         mov [ebx + 0x54 - 0x50],esi //         mov edi,ebx //         add edi,0x18 // // //         //r0 =esp - 0x20 + 8 == esi //         mov edx,0 //         SetKey: //         push esi // //         mov ecx,8 //         add ecx,edx //         movzx eax,word ptr [ebx + ecx] //         add edx,2 // //         mov ecx,eax //         shl eax,1 //         add eax,ecx //         add esi,eax // //         mov cl,[edi] //         mov [esi ],cl //         mov cl,[edi+1] //         mov [esi + 1],cl //         mov cl, [edi + 2] //         mov [esi + 2],cl //         add edi,7 // //         pop esi //         cmp edx, 0x0e //         jnz SetKey // //         pop eax //         mov esp,ebp //         pop ebp //     //         //pop ebx //         //pop esi //         //pop edi    //         //retn 0 //     } // //     return ; // }             int AscToHex(unsigned char * Asc,int AscLen, unsigned char * Hex) {     unsigned char Table[] = "0123456789abcdef";     unsigned int Index = 0;     unsigned int Cnt = 0;     unsigned int Counter = 0;     unsigned char Tmp = 0;       for (Cnt = 0; Cnt < AscLen; )     {         for (Index = 0; Index < 16; Index ++)         {             if ( Asc[Cnt] == Table[Index] )             {                 Tmp = Index << 4;             }         }           Cnt ++;           for (Index = 0; Index < 16; Index ++)         {             if ( Asc[Cnt] == Table[Index] )             {                 Tmp = Tmp | Index;             }         }           Cnt ++;           Hex[Counter] = Tmp;         Counter ++ ;     }       return Counter; }

上面的接口很简单，入口是sub_183C，最后的Flag字段代表要不要做md5验证，如果要的话，执行sub_C49C，否则执行sub_C62C函数。其中的sub_C2C4调用sub_C160和sub_C160，这几个函数的作用是计算md5值。sub_C340是主要加解密函数，其中的数学原理本文不做进一步研究。有些细节我也是模棱两可，只是照抄ida的反汇编后的伪C代码。

这个项目是我经历过难度最大最复杂的工程。
逆向过程持续了差不多一个月的时间，从java层smali插桩输入日志、观察参数，推导数据执行流程，到so层ARM反汇编过程。刚开始做的最频繁的，还是smali插桩分析。因为android程序用的arm汇编，解密程序是x86机器，需要将有些Arm汇编翻译为x86指令。
而在so层面，除了少量arm指令代码，将ida的伪代码直接拷贝到vs工程里编译是ok的，但在运行时解密结果是错的，因为这个原因，自己卡在这里好多天，后来偶然的机会纠正了这个错误，以至于到后来，到底是伪c代码和arm转x86汇编部分，哪里错了我都不记得了。

因为整个通信基本上都是加密数据通信，java层封装的各种加解密接口非常之多，我只能挑选某些地方插桩，最后找到从java层的native接口到进入so的入口：

该程序的so库文件罗列如下：

本程序第一个数据包的解密密钥："DFG#$%^#%$RGHR(&*M<><"，解密算法sub_183C。第一个pos或者get数据包中去掉http包头后，数据部分用这个密钥解密后，可以得到客户端登录信息，比如IMEI,IMSI,手机号等。同时，该数据包中还有一个密钥，该密钥用于解密服务器返回的数据包，结构的名称是“GetUserIdentity”，前缀一般是"\x0b\x8c\x98\x0c\xa8\x0c"，是一个tlv数据结构，具体含义不明。

服务器端返回的数据包中包含另一个16(或许是21)字节的密钥，他所在的格式名称是“GetUserIdentityResp”，解密算法也是sub_183C。该密钥是字符串格式化的，需要转化为二进制后用到上的密钥解密，解密之后的16个字节就是通信过程中通讯录的密钥datakey。

当客户端和服务器通讯录同步时，先用密钥"DFG#$%^#%$RGHR(&*M<><"调用sub_183C函数解密，然后利用上面的密钥datakey再次调用sub_183C函数，对第一次解密后的数据再次解密，即可得到明文数据。

解密后的数据如下：

该程序所有的文本数据都是先转化为utf8和base64，然后先加密后压缩传输的。

其中的base64编码：
44CQ6YKu5YKo6ZO26KGM44CR5oKo5bC+5Y+3OTc4OeeahOmTtuihjOWNoeato+WcqOeUs+ivt+W8gOmAmumCruWCqOmTtuihjOaUr+S7mOWuneW/q+aNt+aUr+S7mO+8jOmqjOivgeegge+8mjQ2NzA5NO+8jOW/q+aNt+aUr+S7mOWPr+iDveS8muW4puadpei+g+mrmOeahOi1hOmHkeaNn+WksemjjumZqe+8jOivt+iwqOaFjuaTjeS9nOOAglvlt6XkvZzkurrlkZjkuI3kvJrntKLlj5bvvIzor7fli7/ms4TpnLJd

解码后是：【邮储银行】您尾号9789的银行卡正在申请开通邮储银行支付宝快捷支付，验证码：467094，快捷支付可能会带来较高的资金损失风险，请谨慎操作。[工作人员不会索取，请勿泄露]

自此，整个程序逆向的框架基本完毕。其中有个java层smali插桩的问题，那会刚接触android，但并不知道有个叫做xposed的神器，因此都是每次手动编写java，反汇编为smali后，将之插入到apk反汇编后的smali中，再次对apk的smali打包并签名，最后安装运行。

该程序还有一个孪生兄弟程序，叫做xxx电话本。该程序还有一个大名鼎鼎的大哥程序，叫做xxx信。他们初始化密钥相同：@#%^SEF#$Sddhfvh，而且解密过程更简单，数据解压缩后直接调用sub_183C函数即可。

当时的版本号是6.0.0，但是不到一年之后，程序进行了更新，改为了RSA非对称方式加解密，因此此算法早已彻底失效。

程序样本在附件中可下载。

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上传的附件：

• 6.0.0.apk （4.42MB，10次下载）