c加密代码（加密与解密c语言编写）

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本文目录一览：

• 1、简单的C语言加密程序？
• 2、c语言编写加密程序
• 3、C语言字符串加密
• 4、C语言编程代码加密

简单的C语言加密程序？

#include

#include

main()

{

intkey;

charch;

printf("\n请输入密钥：");

scanf("%d"，key);

printf("得到对应明文如下：");

while((ch=getchar())!='\r')

(ch+key)122?putchar(ch-122+33+key):

((ch+key)33?putchar(ch+122+key):putchar(ch+key));

}

输入输出如下：

请输入密钥：20addse

得到对应明文如下：uxx.y

你先输入一个任意的整数，如20，然后在键盘上输入一段任意的字符如addse

按回车键结束，就会得到结果如：uxx.y

下面是另一组输入输出：

请输入密钥：35asjRYIRER!@#$^^*

得到对应明文如下：+=4u#luhuDcFG((MI-

具体是如何加密，你应该能看懂，就是用一个三目运算符?:控制。

c语言编写加密程序

#include stdio.h

#include string.h

#include "global.h"

#include "md5.h"

#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 MD5Transform PROTO_LIST ((UINT4 [4], unsigned char

[64]));

static void Encode PROTO_LIST

((unsigned char *, UINT4 *, unsigned int));

static void Decode PROTO_LIST

((UINT4 *, unsigned char *, unsigned int));

static void MD5_memcpy PROTO_LIST ((POINTER, POINTER, unsigned

int));

static void MD5_memset PROTO_LIST ((POINTER, int, unsigned int));

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) + (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); \

}

void MD5Init (context)

MD5_CTX *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 MD5Update (context, input, inputLen)

MD5_CTX *context;

unsigned char *input;

unsigned int inputLen;

{

unsigned int i, index, partLen;

index = (unsigned int)((context-count[0] 3) 0x3F);

if ((context-count[0] += ((UINT4)inputLen 3)) ((UINT4)inputLen 3))

context-count[1]++;

context-count[1] += ((UINT4)inputLen 29);

partLen = 64 - index;

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;

MD5_memcpy((POINTER)context-buffer[index], (POINTER)input[i],inputLen-i);

}

void MD5Final (digest, context)

unsigned char digest[16];

MD5_CTX *context;

{

unsigned char bits[8];

unsigned int index, padLen;

Encode (bits, context-count, 8);

index = (unsigned int)((context-count[0] 3) 0x3f);

padLen = (index 56) ? (56 - index) : (120 - index);

MD5Update (context, PADDING, padLen);

MD5Update (context, bits, 8);

Encode (digest, context-state, 16);

MD5_memset ((POINTER)context, 0, sizeof (*context));

}

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);

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;

MD5_memset ((POINTER)x, 0, sizeof (x));

}

static void Encode (output, input, len)

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);

}

}

static void Decode (output, input, len)

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);

}

static void MD5_memcpy (output, input, len)

POINTER output;

POINTER input;

unsigned int len;

{

unsigned int i;

for (i = 0; i len; i++)

output[i] = input[i];

}

static void MD5_memset (output, value, len)

POINTER output;

int value;

unsigned int len;

{

unsigned int i;

for (i = 0; i len; i++)

((char *)output)[i] = (char)value;

}

#ifndef MD

#define MD 5

#endif

#define TEST_BLOCK_LEN 1000

#define TEST_BLOCK_COUNT 1000

static void MDString PROTO_LIST ((char *));

static void MDPrint PROTO_LIST ((unsigned char [16]));

#define MD_CTX MD5_CTX

#define MDInit MD5Init

#define MDUpdate MD5Update

#define MDFinal MD5Final

int main (int argc, char *argv[])

{

int i;

if (argc 1)

{ MDString(argv[1]);

return (0);

}

}

static void MDString (char *string)

{

MD_CTX context;

unsigned char digest[16];

unsigned int len = strlen (string);

MDInit (context);

MDUpdate (context, string, len);

MDFinal (digest, context);

printf ("MD%d (\"%s\") = ", MD, string);

MDPrint (digest);

printf ("\n");

}

static void MDPrint (unsigned char digest[16])

{

unsigned int i;

for (i = 0; i 16; i++)

printf ("%02x", digest[i]);

}

C语言字符串加密

问题不小，你表面用的是C

但是，好多地方不符合C的语法

，，比如：

for

(int

i=0;

str[i]

!=

'\0';

i++)

还有，就是你好像没有弄清楚

，你要做什么似的，有好多无用的东西，

就像你的函数里的，key

，虽然你提到key了，但是你根本没有使用key，你只是使用45来进行加密，，还有就是一个文件

的大小，是不确定的，你用一个100个字符的字符串来存，有点那个不安全了，，如果稍长一点就会出问题，产生运行时错误。其实你这个加密和解密是一个可逆过程，用一个函数，就可以了，具体你想要的也不是太明白，就给你弄了一个简单一点加密和解密程序

，输入输出不是同一个文件

，不知道是不是你想要的。

#include

#include

#include

void

Decrypt()

{

char

fname[FILENAME_MAX];

char

fname2[FILENAME_MAX];

FILE*

fp;

FILE*

fp1;

int

key;

char

c;

printf("输入要加/解密文件的路径:\n");

scanf("%s",

fname);

printf("请输入密钥:\n");

scanf("%d",key);

strcpy(fname2,fname);

strcat(fname2,".txt");

if(

(fp

=

fopen(fname,"r+"))

==

NULL)

{

printf("error");

exit(1);

}

if(

(fp1

=

fopen(fname2,"w+"))

==

NULL)

{

printf("error");

exit(1);

}

while(

(c

=

fgetc(fp))

!=

EOF)

{

c

=

c^key;

fputc(c,fp1);

}

fcloseall();

}

int

main()

{

Decrypt();

return

0;

}

如果想看一些好一点的加密算法

，我这里有一些，联系我发给你

，，

C语言编程代码加密

例如：简单的移位加密可以这样

FILE *fp=fopen("test.txt","r");

FILE *fp1=fopen("new.txt","w");

while((c=fgetc(fp))!=EOF)

fputc(c+1,fp1);//逐个读取全部字符，ASCII值+1并保存到另一个文件

然后可以remove("test.txt");//删除文件

或者读取new.txt再写回test.txt

解密就是ASCII值-1

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