C语言加密（c语言加密程序）
C语言加密（c语言加密程序）
#include stdio.h
void main()
{
int a[5]; /* 存储各位上的数字 */
int num, temp, encripy; /* num是要输入的数，temp是交换时用来存储临时值，encripy是加密后的数据 */
int i;
do
{
printf("Please input the number:");
scanf("%d",num);
if(!(num/10000 !=0 num/100000==0))
printf("Data error!\n");
}while(!(num/10000 !=0 num/100000==0));
a[0] = num/10000%10; /* 求各位上的数字 */
a[1] = num/1000%10;
a[2] = num/100%10; /* 百位上的数字 */
a[3] = num/10%10; /* 十位上的数字 */
a[4] = num%10; /* 个位上的数字 */
for(i = 0; i 5; ++i) /* 开始加密 */
a[i] = (a[i] + 8)%10;
temp = a[0]; /* 交换位置开始 */
a[0] = a[3];
a[3] = temp;
temp = a[1];
a[1] = a[2];
a[2] = temp; /* 交换位置结束同时加密结束 */
encripy = a[0]*10000 + a[1]*1000 + a[2]*100 + a[3]*10 + a[4]; /* 加密后的数据 */
printf("\nThe scourse number: %d\n", num); /* 输出原数据 */
printf("\nEncripy the number: %d\n\n", encripy); /* 输出加密后的数据 */
}
在VC6.0成功运行，希望对你有帮助!
我没注意只要小写，我写的是大小写都可以的，另外附送输入验证。
#include stdio.h
#include string.h
int main()
{
char str[]="00000",str2[]="00000",*p=str,*p2=str2;
printf("输入5个字母：");
while(*p!=0)
{
scanf("%c",p);
if(*p=='\n')
continue;
if(*p'A'||(*p'Z'*p'a') || *p'z') //输入验证，必须是字母
{
printf("只能输入字母，请重新输入\n");
p=str;
p2=str2;
fflush(stdin);//输入有错重新输入前清空缓冲区。fflush属于c扩展函数，正常使用没问题，如需在linux ggc上使用，考虑多次调用getchar函数来清空
}
else
{
*p2=(*p)+4;
if(*p290 *p297) //大写字母加4，最大位不超出
*p2='A'+(*p2-90)-1;
if(*p2122) //小写字母加4，最大位不超出
*p2='a'+(*p2-122)-1;
p2++;
p++;
}
}
printf("原字符串为：%s\n加密后的字符串为：%s\n",str,str2);
return 0;
}
C语言设计一个简单的加密解密程序如下：
加密程序代码：
#includestdio.h
main()
{
char
c,filename[20];
FILE
*fp1,*fp2;
printf("请输入待加密的文件名:\n");
scanf("%s",filename);
fp1=fopen(filename,"r");
fp2=fopen("miwen.txt","w");
do
{
c=fgetc(fp1);
if(c=32c=126)
{
c=c-32;
c=126-c;
}
if(c!=-1)
fprintf(fp2,"%c",c);
}
while(c!=-1);
}
解密程序代码：
#includestdio.h
#includestring.h
main()
{
char
c,filename[20];
char
yanzhengma[20];
FILE
*fp1,*fp2;
printf("请输入待解密文件名:\n");
scanf("%s",filename);
printf("请输入验证码:\n");
scanf("%s",yanzhengma);
if(strcmp(yanzhengma,"shan")==0)
{
fp1=fopen(filename,"r");
fp2=fopen("yuanwen.txt","w");
do
{
c=fgetc(fp1);
if(c=32c=126)
{
c=126-c;
c=32+c;
}
if(c!=-1)
fprintf(fp2,"%c",c);
}
while(c!=-1);
}
else
{
printf("验证码错误！请重新输入:\n");
scanf("%s",filename);
}
}
unsigned char* encrypt(unsigned char* psw, int enc) {
int sum = 0, i;
if (enc) {
for (i = 0; i 6; i++) {
psw[i] -= 15;
sum += psw[i];
}
psw[6] = (unsigned char) sum;
psw[7] = 0;
}
else {
for (i = 0; i 6; i++) {
sum += psw[i];
psw[i] += 15;
}
if ((unsigned char)sum != psw[6]) {
printf("Bad password\n");
psw[0] = 0;
return psw;
}
else {
psw[6] = 0;
}
}
for (i = 0; i 3;i++) {
unsigned char t = psw[i];
psw[i] = psw[5-i];
psw[5-i] = t;
}
return psw;
}
int main()
{
unsigned char psw[128];
scanf("%s", psw);
printf("encode to:%s\n", encrypt(psw, 1));
printf("decode to:%s\n", encrypt(psw, 0));
return 0;
}
main.cpp
#include stdio.h
#include string.h
#include stdlib.h
#include "md5.c"
int main(int argc, char* argv[])
{
int i;
unsigned char encrypt[] = "admin";//21232f297a57a5a743894a0e4a801fc3
unsigned char decrypt[16];
MD5_CTX md5;
MD5Init(md5);
MD5Update(md5, encrypt, strlen((char*)encrypt));
MD5Final(md5, decrypt);
printf("加密前:%s\n加密后:", encrypt);
for (i = 0; i 16; i++)
{
printf("%02x", decrypt[i]);
}
getchar();
return 0;
}
md5.c
#include memory.h
#include "md5.h"
unsigned char PADDING[] = { 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 };
void MD5Init(MD5_CTX* context)
{
context-count[0] = 0;
context-count[1] = 0;
context-state[0] = 0x67452301;
context-state[1] = 0xEFCDAB89;
context-state[2] = 0x98BADCFE;
context-state[3] = 0x10325476;
}
void MD5Update(MD5_CTX* context, unsigned char* input, unsigned int inputlen)
{
unsigned int i = 0, index = 0, partlen = 0;
index = (context-count[0] 3) 0x3F;
partlen = 64 - index;
context-count[0] += inputlen 3;
if (context-count[0] (inputlen 3))
context-count[1]++;
context-count[1] += inputlen 29;
if (inputlen = partlen)
{
memcpy(context-buffer[index], input, partlen);
MD5Transform(context-state, context-buffer);
for (i = partlen; i + 64 = inputlen; i += 64)
MD5Transform(context-state, input[i]);
index = 0;
}
else
{
i = 0;
}
memcpy(context-buffer[index], input[i], inputlen - i);
}
void MD5Final(MD5_CTX* context, unsigned char digest[16])
{
unsigned int index = 0, padlen = 0;
unsigned char bits[8];
index = (context-count[0] 3) 0x3F;
padlen = (index 56) ? (56 - index) : (120 - index);
MD5Encode(bits, context-count, 8);
MD5Update(context, PADDING, padlen);
MD5Update(context, bits, 8);
MD5Encode(digest, context-state, 16);
}
void MD5Encode(unsigned char* output, unsigned int* input, unsigned int len)
{
unsigned int i = 0, j = 0;
while (j len)
{
output[j] = input[i] 0xFF;
output[j + 1] = (input[i] 8) 0xFF;
output[j + 2] = (input[i] 16) 0xFF;
output[j + 3] = (input[i] 24) 0xFF;
i++;
j += 4;
}
}
void MD5Decode(unsigned int* output, unsigned char* input, unsigned int len)
{
unsigned int i = 0, j = 0;
while (j len)
{
output[i] = (input[j]) |
(input[j + 1] 8) |
(input[j + 2] 16) |
(input[j + 3] 24);
i++;
j += 4;
}
}
void MD5Transform(unsigned int state[4], unsigned char block[64])
{
unsigned int a = state[0];
unsigned int b = state[1];
unsigned int c = state[2];
unsigned int d = state[3];
unsigned int x[64];
MD5Decode(x, block, 64);
FF(a, b, c, d, x[0], 7, 0xd76aa478); /* 1 */
FF(d, a, b, c, x[1], 12, 0xe8c7b756); /* 2 */
FF(c, d, a, b, x[2], 17, 0x242070db); /* 3 */
FF(b, c, d, a, x[3], 22, 0xc1bdceee); /* 4 */
FF(a, b, c, d, x[4], 7, 0xf57c0faf); /* 5 */
FF(d, a, b, c, x[5], 12, 0x4787c62a); /* 6 */
FF(c, d, a, b, x[6], 17, 0xa8304613); /* 7 */
FF(b, c, d, a, x[7], 22, 0xfd469501); /* 8 */
FF(a, b, c, d, x[8], 7, 0x698098d8); /* 9 */
FF(d, a, b, c, x[9], 12, 0x8b44f7af); /* 10 */
FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
/* Round 2 */
GG(a, b, c, d, x[1], 5, 0xf61e2562); /* 17 */
GG(d, a, b, c, x[6], 9, 0xc040b340); /* 18 */
GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
GG(b, c, d, a, x[0], 20, 0xe9b6c7aa); /* 20 */
GG(a, b, c, d, x[5], 5, 0xd62f105d); /* 21 */
GG(d, a, b, c, x[10], 9, 0x2441453); /* 22 */
GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
GG(b, c, d, a, x[4], 20, 0xe7d3fbc8); /* 24 */
GG(a, b, c, d, x[9], 5, 0x21e1cde6); /* 25 */
GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
GG(c, d, a, b, x[3], 14, 0xf4d50d87); /* 27 */
GG(b, c, d, a, x[8], 20, 0x455a14ed); /* 28 */
GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
GG(d, a, b, c, x[2], 9, 0xfcefa3f8); /* 30 */
GG(c, d, a, b, x[7], 14, 0x676f02d9); /* 31 */
GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */
/* Round 3 */
HH(a, b, c, d, x[5], 4, 0xfffa3942); /* 33 */
HH(d, a, b, c, x[8], 11, 0x8771f681); /* 34 */
HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
HH(a, b, c, d, x[1], 4, 0xa4beea44); /* 37 */
HH(d, a, b, c, x[4], 11, 0x4bdecfa9); /* 38 */
HH(c, d, a, b, x[7], 16, 0xf6bb4b60); /* 39 */
HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
HH(d, a, b, c, x[0], 11, 0xeaa127fa); /* 42 */
HH(c, d, a, b, x[3], 16, 0xd4ef3085); /* 43 */
HH(b, c, d, a, x[6], 23, 0x4881d05); /* 44 */
HH(a, b, c, d, x[9], 4, 0xd9d4d039); /* 45 */
HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
HH(b, c, d, a, x[2], 23, 0xc4ac5665); /* 48 */
/* Round 4 */
II(a, b, c, d, x[0], 6, 0xf4292244); /* 49 */
II(d, a, b, c, x[7], 10, 0x432aff97); /* 50 */
II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
II(b, c, d, a, x[5], 21, 0xfc93a039); /* 52 */
II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
II(d, a, b, c, x[3], 10, 0x8f0ccc92); /* 54 */
II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
II(b, c, d, a, x[1], 21, 0x85845dd1); /* 56 */
II(a, b, c, d, x[8], 6, 0x6fa87e4f); /* 57 */
II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
II(c, d, a, b, x[6], 15, 0xa3014314); /* 59 */
II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
II(a, b, c, d, x[4], 6, 0xf7537e82); /* 61 */
II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
II(c, d, a, b, x[2], 15, 0x2ad7d2bb); /* 63 */
II(b, c, d, a, x[9], 21, 0xeb86d391); /* 64 */
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
}
md5.h
#ifndef MD5_H
#define MD5_H
typedef struct
{
unsigned int count[2];
unsigned int state[4];
unsigned char buffer[64];
}MD5_CTX;
#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 + ac; \
a = ROTATE_LEFT(a,s); \
a += b; \
}
#define GG(a,b,c,d,x,s,ac) \
{ \
a += G(b,c,d) + x + ac; \
a = ROTATE_LEFT(a,s); \
a += b; \
}
#define HH(a,b,c,d,x,s,ac) \
{ \
a += H(b,c,d) + x + ac; \
a = ROTATE_LEFT(a,s); \
a += b; \
}
#define II(a,b,c,d,x,s,ac) \
{ \
a += I(b,c,d) + x + ac; \
a = ROTATE_LEFT(a,s); \
a += b; \
}
void MD5Init(MD5_CTX* context);
void MD5Update(MD5_CTX* context, unsigned char* input, unsigned int inputlen);
void MD5Final(MD5_CTX* context, unsigned char digest[16]);
void MD5Transform(unsigned int state[4], unsigned char block[64]);
void MD5Encode(unsigned char* output, unsigned int* input, unsigned int len);
void MD5Decode(unsigned int* output, unsigned char* input, unsigned int len);
#endif
