TEA加密算法的CC++实现（转载）

技术2026-05-03 1

TEA加密算法的C/C++实现

转载自 http://www.cppblog.com/ant/archive/2007/10/12/31326.html

TEA(Tiny Encryption Algorithm) 是一种简单高效的加密算法，以加密解密速度快，实现简单著称。算法真的很简单，TEA算法每一次可以操作64-bit(8-byte)，采用128-bit(16-byte)作为key，算法采用迭代的形式，推荐的迭代轮数是64轮，最少32轮。目前我只知道QQ一直用的是16轮TEA。没什么好说的，先给出C语言的源代码(默认是32轮)：

1 void encrypt(unsigned long * v, unsigned long * k) { 2 unsigned long y = v[ 0 ], z = v[ 1 ], sum = 0 , i; /* set up */ 3 unsigned long delta = 0x9e3779b9 ; /* a key schedule constant */ 4 unsigned long a = k[ 0 ], b = k[ 1 ], c = k[ 2 ], d = k[ 3 ]; /* cache key */ 5 for (i = 0 ; i < 32 ; i ++ ) { /* basic cycle start */ 6 sum += delta; 7 y += ((z << 4 ) + a) ^ (z + sum) ^ ((z >> 5 ) + b); 8 z += ((y << 4 ) + c) ^ (y + sum) ^ ((y >> 5 ) + d); /* end cycle */ 9 } 10 v[ 0 ] = y; 11 v[ 1 ] = z; 12 } 13 14 void decrypt(unsigned long * v, unsigned long * k) { 15 unsigned long y = v[ 0 ], z = v[ 1 ], sum = 0xC6EF3720 , i; /* set up */ 16 unsigned long delta = 0x9e3779b9 ; /* a key schedule constant */ 17 unsigned long a = k[ 0 ], b = k[ 1 ], c = k[ 2 ], d = k[ 3 ]; /* cache key */ 18 for (i = 0 ; i < 32 ; i ++ ) { /* basic cycle start */ 19 z -= ((y << 4 ) + c) ^ (y + sum) ^ ((y >> 5 ) + d); 20 y -= ((z << 4 ) + a) ^ (z + sum) ^ ((z >> 5 ) + b); 21 sum -= delta; /* end cycle */ 22 } 23 v[ 0 ] = y; 24 v[ 1 ] = z; 25 }

C语言写的用起来当然不方便，没关系，用C++封装以下就OK了： util.h

1 #ifndef UTIL_H 2 #define UTIL_H 3 4 #include < string > 5 #include < cstdlib > 6 7 typedef unsigned char byte ; 8 typedef unsigned long ulong; 9 10 /* 11 *convert int to hex char. 12 *example:10 -> 'A',15 -> 'F' 13 */ 14 char intToHexChar( int x); 15 16 /* 17 *convert hex char to int. 18 *example:'A' -> 10,'F' -> 15 19 */ 20 int hexCharToInt( char hex); 21 22 using std::string; 23 /* 24 *convert a byte array to hex string. 25 *hex string format example:"AF B0 80 7D" 26 */ 27 string bytesToHexString( const byte * in, size_t size); 28 29 /* 30 *convert a hex string to a byte array. 31 *hex string format example:"AF B0 80 7D" 32 */ 33 size_t hexStringToBytes( const string & str, byte * out); 34 35 #endif /* UTIL_H */

util.cpp

1 #include " util.h " 2 #include < vector > 3 4 using namespace std; 5 6 char intToHexChar( int x) { 7 static const char HEX[ 16 ] = { 8 ' 0 ' , ' 1 ' , ' 2 ' , ' 3 ' , 9 ' 4 ' , ' 5 ' , ' 6 ' , ' 7 ' , 10 ' 8 ' , ' 9 ' , ' A ' , ' B ' , 11 ' C ' , ' D ' , ' E ' , ' F ' 12 }; 13 return HEX[x]; 14 } 15 16 int hexCharToInt( char hex) { 17 hex = toupper(hex); 18 if (isdigit(hex)) 19 return (hex - ' 0 ' ); 20 if (isalpha(hex)) 21 return (hex - ' A ' + 10 ); 22 return 0 ; 23 } 24 25 string bytesToHexString( const byte * in, size_t size) { 26 string str; 27 for (size_t i = 0 ; i < size; ++ i) { 28 int t = in[i]; 29 int a = t / 16 ; 30 int b = t % 16 ; 31 str.append( 1 , intToHexChar(a)); 32 str.append( 1 , intToHexChar(b)); 33 if (i != size - 1 ) 34 str.append( 1 , ' ' ); 35 } 36 return str; 37 } 38 39 size_t hexStringToBytes( const string & str, byte * out) { 40 41 vector < string > vec; 42 string::size_type currPos = 0 , prevPos = 0 ; 43 while ((currPos = str.find( ' ' , prevPos)) != string::npos) { 44 string b(str.substr(prevPos, currPos - prevPos)); 45 vec.push_back(b); 46 prevPos = currPos + 1 ; 47 } 48 if (prevPos < str.size()) { 49 string b(str.substr(prevPos)); 50 vec.push_back(b); 51 } 52 typedef vector < string > ::size_type sz_type; 53 sz_type size = vec.size(); 54 for (sz_type i = 0 ; i < size; ++ i) { 55 int a = hexCharToInt(vec[i][ 0 ]); 56 int b = hexCharToInt(vec[i][ 1 ]); 57 out[i] = a * 16 + b; 58 } 59 return size; 60 }

tea.h

1 #ifndef TEA_H 2 #define TEA_H 3 4 /* 5 *for htonl,htonl 6 *do remember link "ws2_32.lib" 7 */ 8 #include < winsock2.h > 9 #include " util.h " 10 11 class TEA { 12 public : 13 TEA( const byte * key, int round = 32 , bool isNetByte = false ); 14 TEA( const TEA & rhs); 15 TEA & operator = ( const TEA & rhs); 16 void encrypt( const byte * in, byte * out); 17 void decrypt( const byte * in, byte * out); 18 private : 19 void encrypt( const ulong * in, ulong * out); 20 void decrypt( const ulong * in, ulong * out); 21 ulong ntoh(ulong netlong) { return _isNetByte ? ntohl(netlong) : netlong; } 22 ulong hton(ulong hostlong) { return _isNetByte ? htonl(hostlong) : hostlong; } 23 private : 24 int _round; // iteration round to encrypt or decrypt 25 bool _isNetByte; // whether input bytes come from network 26 byte _key[ 16 ]; // encrypt or decrypt key 27 }; 28 29 #endif /* TEA_H */

tea.cpp

1 #include " tea.h " 2 #include < cstring > // for memcpy,memset 3 4 using namespace std; 5 6 TEA::TEA( const byte * key, int round /* = 32 */ , bool isNetByte /* = false */ ) 7 :_round(round) 8 ,_isNetByte(isNetByte) { 9 if (key != 0 ) 10 memcpy(_key, key, 16 ); 11 else 12 memset(_key, 0 , 16 ); 13 } 14 15 TEA::TEA( const TEA & rhs) 16 :_round(rhs._round) 17 ,_isNetByte(rhs._isNetByte) { 18 memcpy(_key, rhs._key, 16 ); 19 } 20 21 TEA & TEA::operator = ( const TEA & rhs) { 22 if ( & rhs != this ) { 23 _round = rhs._round; 24 _isNetByte = rhs._isNetByte; 25 memcpy(_key, rhs._key, 16 ); 26 } 27 return * this ; 28 } 29 30 void TEA::encrypt( const byte * in, byte * out) { 31 encrypt(( const ulong * )in, (ulong * )out); 32 } 33 34 void TEA::decrypt( const byte * in, byte * out) { 35 decrypt(( const ulong * )in, (ulong * )out); 36 } 37 38 void TEA::encrypt( const ulong * in, ulong * out) { 39 40 ulong * k = (ulong * )_key; 41 register ulong y = ntoh(in[ 0 ]); 42 register ulong z = ntoh(in[ 1 ]); 43 register ulong a = ntoh(k[ 0 ]); 44 register ulong b = ntoh(k[ 1 ]); 45 register ulong c = ntoh(k[ 2 ]); 46 register ulong d = ntoh(k[ 3 ]); 47 register ulong delta = 0x9E3779B9 ; /* (sqrt(5)-1)/2*2^32 */ 48 register int round = _round; 49 register ulong sum = 0 ; 50 51 while (round -- ) { /* basic cycle start */ 52 sum += delta; 53 y += ((z << 4 ) + a) ^ (z + sum) ^ ((z >> 5 ) + b); 54 z += ((y << 4 ) + c) ^ (y + sum) ^ ((y >> 5 ) + d); 55 } /* end cycle */ 56 out[ 0 ] = ntoh(y); 57 out[ 1 ] = ntoh(z); 58 } 59 60 void TEA::decrypt( const ulong * in, ulong * out) { 61 62 ulong * k = (ulong * )_key; 63 register ulong y = ntoh(in[ 0 ]); 64 register ulong z = ntoh(in[ 1 ]); 65 register ulong a = ntoh(k[ 0 ]); 66 register ulong b = ntoh(k[ 1 ]); 67 register ulong c = ntoh(k[ 2 ]); 68 register ulong d = ntoh(k[ 3 ]); 69 register ulong delta = 0x9E3779B9 ; /* (sqrt(5)-1)/2*2^32 */ 70 register int round = _round; 71 register ulong sum = 0 ; 72 73 if (round == 32 ) 74 sum = 0xC6EF3720 ; /* delta << 5 */ 75 else if (round == 16 ) 76 sum = 0xE3779B90 ; /* delta << 4 */ 77 else 78 sum = delta * round; 79 80 while (round -- ) { /* basic cycle start */ 81 z -= ((y << 4 ) + c) ^ (y + sum) ^ ((y >> 5 ) + d); 82 y -= ((z << 4 ) + a) ^ (z + sum) ^ ((z >> 5 ) + b); 83 sum -= delta; 84 } /* end cycle */ 85 out[ 0 ] = ntoh(y); 86 out[ 1 ] = ntoh(z); 87 }

需要说明的是TEA的构造函数： TEA(const byte *key, int round = 32, bool isNetByte = false); 1.key - 加密或解密用的128-bit(16byte)密钥。 2.round - 加密或解密的轮数，常用的有64，32，16。 3.isNetByte - 用来标记待处理的字节是不是来自网络，为true时在加密/解密前先要转换成本地字节，执行加密/解密，然后再转换回网络字节。偷偷告诉你，QQ就是这样做的！最后当然少不了测试代码： test.cpp

1 #include " tea.h " 2 #include " util.h " 3 #include < iostream > 4 5 using namespace std; 6 7 int main() { 8 9 const string plainStr( " AD DE E2 DB B3 E2 DB B3 " ); 10 const string keyStr( " 3A DA 75 21 DB E2 DB B3 11 B4 49 01 A5 C6 EA D4 " ); 11 const int SIZE_IN = 8 , SIZE_OUT = 8 , SIZE_KEY = 16 ; 12 byte plain[SIZE_IN], crypt[SIZE_OUT], key[SIZE_KEY]; 13 14 size_t size_in = hexStringToBytes(plainStr, plain); 15 size_t size_key = hexStringToBytes(keyStr, key); 16 17 if (size_in != SIZE_IN || size_key != SIZE_KEY) 18 return - 1 ; 19 20 cout << " Plain: " << bytesToHexString(plain, size_in) << endl; 21 cout << " Key : " << bytesToHexString(key, size_key) << endl; 22 23 TEA tea(key, 16 , true ); 24 tea.encrypt(plain, crypt); 25 cout << " Crypt: " << bytesToHexString(crypt, SIZE_OUT) << endl; 26 27 tea.decrypt(crypt, plain); 28 cout << " Plain: " << bytesToHexString(plain, SIZE_IN) << endl; 29 return 0 ; 30 }

运行结果： Plain: AD DE E2 DB B3 E2 DB B3 Key : 3A DA 75 21 DB E2 DB B3 11 B4 49 01 A5 C6 EA D4 Crypt: 3B 3B 4D 8C 24 3A FD F2 Plain: AD DE E2 DB B3 E2 DB B3

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