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简单加密算法 这些加密原理非常简单,并且可以由开发人员自由设计加密参数及复杂程度。通过重复多次,或是多种加密方式结合使用,可以达到非常不错的加密效果,完全能够满足一般需求。 1、码表替换 将需加密的每个字符或数字替换成另一个,设计这样一个替换规则表来。 如: a->c b->z … 简单代码如下,可以自定义替换规则表 VOID Test1(BYTE* buf, int len, BYTE* key) { int i,j; char tableA[10]={'a', 'b', 'c', 'd', 'e', 'f', '0', '1', '2', '3'}; char tableB[10]={'0', '1', '2', '3', 'a', 'b', 'c', 'd', 'e', 'f'}; int tablelen = 10; memcpy(key, buf, len); for(i=0; i {
for(j=0; j { if (buf == tableA[j]) { key = tableB[j]; break; } } } } 调用方法: 传入需要加密的字符串codestr,及加密字符串长度,及生成KEY的BUFFER指针,加密函数执行完毕后将KEY存入该BUFFER中。 Test1((BYTE*)codestr, strlen(codestr), key); //将codestr转成key,长度不变 2、取补码 对需加密的每个字节与自定的值取补,生产新的数据。 简单代码
VOID Test2(BYTE* buf, int len, BYTE* key) //取补码 { int i; char table[10]={"emtronix"}; int tablelen = 8; for(i=0; i { key = buf^table[i%8]; } } 调用方法: 传入需要加密的字符串codestr,及加密字符串长度,及生成KEY的BUFFER指针,加密函数执行完毕后将KEY存入该BUFFER中。 Test2((BYTE*)codestr, strlen(codestr), key); //将codestr转成key,长度不变 3、移位处理 对需加密的每个字节交换高低位,或是整体左移或是右移自定义的位数。 简单代码,交换高低位 VOID Test3(BYTE* buf, int len, BYTE* key) //交换高低位 { int i; for(i=0; i { key = ((buf&0xf0)>>4)|((buf&0x0f)<<4); } } 调用方法: 传入需要加密的字符串codestr,及加密字符串长度,及生成KEY的BUFFER指针,加密函数执行完毕后将KEY存入该BUFFER中。 Test3((BYTE*)codestr, strlen(codestr), key); //将codestr转成key,长度不变 4、插入随机无效数据 通过大量原数据及加密后数据的观察,通过计算机暴力计算,也许有破解加密规则的可能性。那么在指定位置加入随机的无效的数据,再进行加密,可以大大增加破解的难度。 简单代码 VOID Test4(BYTE* buf, int len, BYTE* key) //增加无效数据 { int i; for(i=0; i { key[i*2] = buf; key[i*2+1] = rand()&0xff; } } 调用方法: 传入需要加密的字符串codestr,及加密字符串长度,及生成KEY的BUFFER指针,加密函数执行完毕后将KEY存入该BUFFER中。 Test4 ((BYTE*)codestr, strlen(codestr), key); //将codestr转成key,长度增加一倍 5、TEA加密 TEA(tiny Encryption Algorithm)是一种极为简单的对称加密算法,运用比较普遍,它不是通过算法的复杂性来保证的,而是依赖加密的轮数来保证。这种算法采用一个128位的密钥来加密64位的数据明文,能产生一个64位的密文。具有较好的抗差分性能。 代码如下: /********************************************************** Input values: k[4] 128位密钥 v[2] 加密时位明文,解密时位密文 Output values: v[2] 加密时位密文,解密时位明文 **********************************************************/ void tea(DWORD *k, DWORD *v, long N ) //如果N为负值就是解密过程,相应的v就为密文,密钥k一共就有k[0]、k[1]、k[2]、k[3]四个元素 { DWORD DELTA = 0x9e3779b9; /* sqr(5)-1 * 2^31 */ DWORD y=v[0], z=v[1]; //y为明文或密文高位,z为明文或密文低位 DWORD limit,sum=0; //sum为部分和 if(N>0) { /* 加密过程*/ limit=DELTA*N; while(sum!=limit) { //注意:高位和地位交叉运算,利用sum操作的低两位进行密钥的部分选择 y+=((z<<4)^(z>>5)) + (z^sum) + k[sum&3]; sum+=DELTA; z+=((y<<4)^(y>>5)) + (y^sum) + k[(sum>>11)&3]; } } else { /* 解密过程,就是加密算法简单的反向运算*/ sum=DELTA*(-N); while(sum) { z-=((y<<4)^(y>>5)) + (y^sum) + k[(sum>>11)&3]; sum-=DELTA; y-=((z<<4)^(z>>5)) + (z^sum) + k[sum&3]; } } v[0]=y; v[1]=z; } 加密示例 DWORD k[4] = {5, 7, 100, 200}; //加密用的密钥,位,自由设定 DWORD v[2] = {45, 77}; //待加密的数据,位 tea(k, v, 32); //加密32轮,操作后v数组已经变化 tea(k, v, -32); //解密32轮(负数表示解密),解密后v变回原来的{45, 77} 常见加密算法 有一些公开的,著名的加密算法,在很多地方都有应用。比如MD5、哈希加密、RSA及DES加密。这里简单介绍下MD5的加密方法。 MD5加密 MD5被广泛应用在认证应用中,它的好处在于对任何一段数据都能加密成一段唯一对应的KEY。并且即使公布算法,在得知KEY的情况下也无法逆推出原数据。 MD5加密算法可以参考网上资料http://baike.baidu.com/view/7636.htm,生成32位MD5的代码如下。 #include "StdAfx.h"
typedef struct { unsigned int state[4]; unsigned int count[2]; unsigned char buffer[64]; } MD5Context;
void MD5_Init(MD5Context * context); void MD5_Update(MD5Context * context, unsigned char * buf, int len); void MD5_Final(MD5Context * context, 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 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 };
#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)))
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
#define FF(a, b, c, d, x, s, ac) { (a) += F((b), (c), (d)) + (x) + (unsigned int)(ac); (a) = ROTATE_LEFT((a), (s)); (a) += (b); }
#define GG(a, b, c, d, x, s, ac) { (a) += G((b), (c), (d)) + (x) + (unsigned int)(ac); (a) = ROTATE_LEFT((a), (s)); (a) += (b); }
#define HH(a, b, c, d, x, s, ac) { (a) += H((b), (c), (d)) + (x) + (unsigned int)(ac); (a) = ROTATE_LEFT((a), (s)); (a) += (b); }
#define II(a, b, c, d, x, s, ac) { (a) += I((b), (c), (d)) + (x) + (unsigned int)(ac); (a) = ROTATE_LEFT((a), (s)); (a) += (b); }
static void MD5_Encode(unsigned char * output, unsigned int * input, int len) { unsigned int i, j; for (i = 0, j = 0; j < len; i++, j += 4) { output[j] = (unsigned char) (input & 0xff); output[j + 1] = (unsigned char) ((input >> 8) & 0xff); output[j + 2] = (unsigned char) ((input >> 16) & 0xff); output[j + 3] = (unsigned char) ((input >> 24) & 0xff); } }
static void MD5_Decode(unsigned int * output, unsigned char * input, int len) { unsigned int i, j; for (i = 0, j = 0; j < len; i++, j += 4) { output = ((unsigned int) input[j]) | (((unsigned int) input[j + 1]) << 8) | (((unsigned int) input[j + 2]) << 16) | (((unsigned int) input[j + 3]) << 24); } }
static void MD5_Transform(unsigned int state[4], unsigned char block[64]) { unsigned int a = state[0], b = state[1], c = state[2], d = state[3], x[16]; MD5_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; memset((char *) x, 0, sizeof(x)); }
void MD5_Init(MD5Context * context) { context->count[0] = context->count[1] = 0; context->state[0] = 0x67452301; context->state[1] = 0xefcdab89; context->state[2] = 0x98badcfe; context->state[3] = 0x10325476; }
void MD5_Update(MD5Context * context, unsigned char * buf, int len) { unsigned int i, index, partLen; index = (unsigned int) ((context->count[0] >> 3) & 0x3F); if ((context->count[0] += ((unsigned int) len << 3)) < ((unsigned int) len << 3)) context->count[1]++; context->count[1] += ((unsigned int) len >> 29); partLen = 64 - index; if (len >= partLen) { memcpy((char *) &context->buffer[index], (char *) buf, partLen); MD5_Transform(context->state, context->buffer); for (i = partLen; i + 63 < len; i += 64) MD5_Transform(context->state, &buf); index = 0; } else { i = 0; } memcpy((char *) &context->buffer[index], (char *) &buf, len - i); }
void MD5_Final(MD5Context * context, unsigned char digest[16]) { unsigned char bits[8]; unsigned int index, padLen; MD5_Encode(bits, context->count, 8); index = (unsigned int) ((context->count[0] >> 3) & 0x3f); padLen = (index < 56) ? (56 - index) : (120 - index); MD5_Update(context, PADDING, padLen); MD5_Update(context, bits, 8); MD5_Encode(digest, context->state, 16); memset((char *) context, 0, sizeof(*context)); }
void GetMD5Code(BYTE* pBuf, int nSize, char pCode[34]) { MD5Context context; unsigned char buff[16]; MD5_Init(&context); MD5_Update(&context, pBuf, nSize); MD5_Final(&context, buff); for(int j = 0;j < 16; j++){ sprintf(pCode + j * 2, "%x", (buff[j] & 0xF0)>>4); sprintf(pCode + j * 2 + 1, "%x", buff[j] & 0x0F); } } 调用方法: 传入需要加密的字符串codestr,及加密字符串长度,及生成KEY的BUFFER指针,加密函数执行完毕后将KEY存入该BUFFER中。 GetMD5Code(codestr, len, (char*)key); 以字符串"emtronix"为例,加密后key = "17f402d9a6251aff2302c01a035d05f4",可以利用网上工具验证是正确的。 哈希加密 哈希加密是用安全散列算法对字符串进行的一种加密。哈希加密有很多种,这里简单介绍一种SHA-256加密,它能将任何字符串加密成256bit的密码,即8个32bit的整形来存储,因为1个整形用16进制的字符串来表示需要8字节,即一共64字节。 #include "StdAfx.h"
#define SHA256_ROTL(a,b) (((a>>(32-b))&(0x7fffffff>>(31-b)))|(a< #define SHA256_SR(a,b) ((a>>b)&(0x7fffffff>>(b-1))) #define SHA256_Ch(x,y,z) ((x&y)^((~x)&z)) #define SHA256_Maj(x,y,z) ((x&y)^(x&z)^(y&z)) #define SHA256_E0(x) (SHA256_ROTL(x,30)^SHA256_ROTL(x,19)^SHA256_ROTL(x,10)) #define SHA256_E1(x) (SHA256_ROTL(x,26)^SHA256_ROTL(x,21)^SHA256_ROTL(x,7)) #define SHA256_O0(x) (SHA256_ROTL(x,25)^SHA256_ROTL(x,14)^SHA256_SR(x,3)) #define SHA256_O1(x) (SHA256_ROTL(x,15)^SHA256_ROTL(x,13)^SHA256_SR(x,10))
void StrSHA256(const char* str, long long length, char* sha256) { char *pp, *ppend; long l, i, W[64], T1, T2, A, B, C, D, E, F, G, H, H0, H1, H2, H3, H4, H5, H6, H7; H0 = 0x6a09e667, H1 = 0xbb67ae85, H2 = 0x3c6ef372, H3 = 0xa54ff53a; H4 = 0x510e527f, H5 = 0x9b05688c, H6 = 0x1f83d9ab, H7 = 0x5be0cd19; long K[64] = { 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2, }; l = length + ((length % 64 > 56) ? (128 - length % 64) : (64 - length % 64)); if (!(pp = (char*)malloc((unsigned long)l))) return; for (i = 0; i < length; pp[i + 3 - 2 * (i % 4)] = str, i++); for (pp[i + 3 - 2 * (i % 4)] = 128, i++; i < l; pp[i + 3 - 2 * (i % 4)] = 0, i++); *((long*)(pp + l - 4)) = length << 3; *((long*)(pp + l - 8)) = length >> 29; for (ppend = pp + l; pp < ppend; pp += 64){ for (i = 0; i < 16; W = ((long*)pp), i++); for (i = 16; i < 64; W = (SHA256_O1(W[i - 2]) + W[i - 7] + SHA256_O0(W[i - 15]) + W[i - 16]), i++); A = H0, B = H1, C = H2, D = H3, E = H4, F = H5, G = H6, H = H7; for (i = 0; i < 64; i++){ T1 = H + SHA256_E1(E) + SHA256_Ch(E, F, G) + K + W; T2 = SHA256_E0(A) + SHA256_Maj(A, B, C); H = G, G = F, F = E, E = D + T1, D = C, C = B, B = A, A = T1 + T2; } H0 += A, H1 += B, H2 += C, H3 += D, H4 += E, H5 += F, H6 += G, H7 += H; } free(pp - l); sprintf(sha256, "%08X%08X%08X%08X%08X%08X%08X%08X", H0, H1, H2, H3, H4, H5, H6, H7); return; } 调用方法: 传入需要加密的字符串codestr,及加密字符串长度,及生成KEY的BUFFER指针,加密函数执行完毕后将KEY存入该BUFFER中。 StrSHA256 (codestr, len, (char*)key); 如需要本文相关测试程序,可以联系英创工程师。
相关阅读:针对MAC地址的应用程序加密方法 |
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