c语言双轨加密算法
A. 用c语言设计了一个加密算法:用a代替z,用b代替y,用c代替x,……,用z代替a。
#include <stdio.h>
int main()
{
char s[100],*p;
printf("请输入字符串 : ");
gets(s);
p = s;
while(*p)
{
if((*p >= 'a') && (*p <= 'z')) /*处理小写*/
{
*p ='z' - *p + 'a';
}
if((*p >= 'A') && (*p <= 'Z')) /*处理大写,同理处理数字亦一样..自己例推*/
{
*p ='Z' - *p + 'A';
}
p++;
}
printf("转换后的字符串为 : %s\n\n",s);
return 0;
}
B. c 语言常用的加密算法——MD5
在C语言中,常用的加密算法主要包括AES、RSA、MD5、SHA-1及Base64编码。
AES加密算法是一种对称加密算法,广泛应用于数据加密。通过OpenSSL库在C语言中实现AES加密。
RSA加密算法为非对称加密算法,使用两把不同的密钥进行加密与解密,是最成熟且常用的非对称加密算法。同样使用OpenSSL库在C语言中实现RSA加密。
MD5算法作为加密散列函数,产生128位散列值,广泛应用于C语言中。通过OpenSSL库实现MD5加密。
SHA-1算法全称为Secure Hash Algorithm 1,用于数字签名、验证、消息摘要等,C语言中通过OpenSSL库实现SHA-1加密。
Base64编码虽非加密算法,但用于隐藏信息,C语言中通过OpenSSL库进行Base64编码与解码。
实现这些算法时通常利用OpenSSL库,因其提供了高效实现,避免了重复开发。
MD5算法在C语言中的实现示例如下:
#include
#include md5.h>
int main() {
char *str = "Hello, world!";
unsigned char digest[MD5_DIGEST_LENGTH];
MD5((unsigned char*) str, strlen(str), digest);
printf("MD5 hash of \"%s\": ", str);
for (int i = 0; i < MD5_DIGEST_LENGTH; i++) {
printf("%02x", digest[i]);
}
printf(" ");
return 0;
}
通过OpenSSL库中的MD5函数,传入字符串与长度,将结果存储在数组中,然后打印数组内容即为MD5散列值。
C. 利用C语言实现移位加密和解密算法
呵呵
这两天刚编了一个
#include<stdio.h>
#include<string.h>
#include<ctype.h>
void main()
{
char a[500];
gets(a);
int n,i;
n = strlen(a);
for(i=0;i<n;i++)
if(a[i]=='y')
a[i]='a';
else if(a[i]=='z')
a[i]='b';
else if (isalpha(a[i]))
a[i] += 2;
printf("%s",a );
}
这个是往后推2的解密。
g fmnc wms bgblr rpylqjyrc gr zw fylb. rfyrq ufyr amknsrcpq ypc dmp. bmgle gr gl zw fylb gq glcddgagclr ylb rfyr'q ufw rfgq rcvr gq qm jmle.
解密试试吧~~
加密的话
改动三个地方就行 自己试试吧 哈哈
D. 关于C语言的加密
'a'的ASC码是97
'b'的ASC码是98
'c'的ASC码是99
... ...
'z'的ASC码是122
明文和密文相对应
如明文:"abc"
密文:"zyw"
当ch1 = 'a'时,ch2 = 'z'
ch1 - 97 = 97 + 25 - ch2
97 - 97 = 97 + 25 - 122 = 0
当ch1 = 'b'时,ch2 = 'y'
ch1 - 97 = 97 + 25 - ch2
98 - 97 = 97 + 25 - 121 = 1
当ch1 = 'c'时,ch2 = 'w'
ch1 - 97 = 97 + 25 - ch2
99 - 97 = 97 + 25 - 120 = 2
ch1 - 97 = 97 + 25 - ch2这实际上是明文与密文的对应关系,也就是他的算法
你可以对明文去设定一个对应关系,就可以得到不同的密文
E. aes加密算法C代码
完整的!
#include "stdio.h"
#include "memory.h"
#include "time.h"
#include "stdlib.h"
#define PLAIN_FILE_OPEN_ERROR -1
#define KEY_FILE_OPEN_ERROR -2
#define CIPHER_FILE_OPEN_ERROR -3
#define OK 1
typedef char ElemType;
/*初始置换表IP*/
int IP_Table[64] = { 57,49,41,33,25,17,9,1,
59,51,43,35,27,19,11,3,
61,53,45,37,29,21,13,5,
63,55,47,39,31,23,15,7,
56,48,40,32,24,16,8,0,
58,50,42,34,26,18,10,2,
60,52,44,36,28,20,12,4,
62,54,46,38,30,22,14,6};
/*逆初始置换表IP^-1*/
int IP_1_Table[64] = {39,7,47,15,55,23,63,31,
38,6,46,14,54,22,62,30,
37,5,45,13,53,21,61,29,
36,4,44,12,52,20,60,28,
35,3,43,11,51,19,59,27,
34,2,42,10,50,18,58,26,
33,1,41,9,49,17,57,25,
32,0,40,8,48,16,56,24};
/*扩充置换表E*/
int E_Table[48] = {31, 0, 1, 2, 3, 4,
3, 4, 5, 6, 7, 8,
7, 8,9,10,11,12,
11,12,13,14,15,16,
15,16,17,18,19,20,
19,20,21,22,23,24,
23,24,25,26,27,28,
27,28,29,30,31, 0};
/*置换函数P*/
int P_Table[32] = {15,6,19,20,28,11,27,16,
0,14,22,25,4,17,30,9,
1,7,23,13,31,26,2,8,
18,12,29,5,21,10,3,24};
/*S盒*/
int S[8][4][16] =
/*S1*/
{{{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
{0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
{4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
{15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}},
/*S2*/
{{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
{3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
{0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
{13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}},
/*S3*/
{{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
{13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
{13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
{1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}},
/*S4*/
{{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
{13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
{10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
{3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}},
/*S5*/
{{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
{14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
{4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
{11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}},
/*S6*/
{{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
{10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
{9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
{4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}},
/*S7*/
{{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
{13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
{1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
{6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}},
/*S8*/
{{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
{1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
{7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
{2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}}};
/*置换选择1*/
int PC_1[56] = {56,48,40,32,24,16,8,
0,57,49,41,33,25,17,
9,1,58,50,42,34,26,
18,10,2,59,51,43,35,
62,54,46,38,30,22,14,
6,61,53,45,37,29,21,
13,5,60,52,44,36,28,
20,12,4,27,19,11,3};
/*置换选择2*/
int PC_2[48] = {13,16,10,23,0,4,2,27,
14,5,20,9,22,18,11,3,
25,7,15,6,26,19,12,1,
40,51,30,36,46,54,29,39,
50,44,32,46,43,48,38,55,
33,52,45,41,49,35,28,31};
/*对左移次数的规定*/
int MOVE_TIMES[16] = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
int ByteToBit(ElemType ch,ElemType bit[8]);
int BitToByte(ElemType bit[8],ElemType *ch);
int Char8ToBit64(ElemType ch[8],ElemType bit[64]);
int Bit64ToChar8(ElemType bit[64],ElemType ch[8]);
int DES_MakeSubKeys(ElemType key[64],ElemType subKeys[16][48]);
int DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]);
int DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]);
int DES_ROL(ElemType data[56], int time);
int DES_IP_Transform(ElemType data[64]);
int DES_IP_1_Transform(ElemType data[64]);
int DES_E_Transform(ElemType data[48]);
int DES_P_Transform(ElemType data[32]);
int DES_SBOX(ElemType data[48]);
int DES_XOR(ElemType R[48], ElemType L[48],int count);
int DES_Swap(ElemType left[32],ElemType right[32]);
int DES_EncryptBlock(ElemType plainBlock[8], ElemType subKeys[16][48], ElemType cipherBlock[8]);
int DES_DecryptBlock(ElemType cipherBlock[8], ElemType subKeys[16][48], ElemType plainBlock[8]);
int DES_Encrypt(char *plainFile, char *keyStr,char *cipherFile);
int DES_Decrypt(char *cipherFile, char *keyStr,char *plainFile);
/*字节转换成二进制*/
int ByteToBit(ElemType ch, ElemType bit[8]){
int cnt;
for(cnt = 0;cnt < 8; cnt++){
*(bit+cnt) = (ch>>cnt)&1;
}
return 0;
}
/*二进制转换成字节*/
int BitToByte(ElemType bit[8],ElemType *ch){
int cnt;
for(cnt = 0;cnt < 8; cnt++){
*ch |= *(bit + cnt)<<cnt;
}
return 0;
}
/*将长度为8的字符串转为二进制位串*/
int Char8ToBit64(ElemType ch[8],ElemType bit[64]){
int cnt;
for(cnt = 0; cnt < 8; cnt++){
ByteToBit(*(ch+cnt),bit+(cnt<<3));
}
return 0;
}
/*将二进制位串转为长度为8的字符串*/
int Bit64ToChar8(ElemType bit[64],ElemType ch[8]){
int cnt;
memset(ch,0,8);
for(cnt = 0; cnt < 8; cnt++){
BitToByte(bit+(cnt<<3),ch+cnt);
}
return 0;
}
/*生成子密钥*/
int DES_MakeSubKeys(ElemType key[64],ElemType subKeys[16][48]){
ElemType temp[56];
int cnt;
DES_PC1_Transform(key,temp);/*PC1置换*/
for(cnt = 0; cnt < 16; cnt++){/*16轮跌代,产生16个子密钥*/
DES_ROL(temp,MOVE_TIMES[cnt]);/*循环左移*/
DES_PC2_Transform(temp,subKeys[cnt]);/*PC2置换,产生子密钥*/
}
return 0;
}
/*密钥置换1*/
int DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]){
int cnt;
for(cnt = 0; cnt < 56; cnt++){
tempbts[cnt] = key[PC_1[cnt]];
}
return 0;
}
/*密钥置换2*/
int DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]){
int cnt;
for(cnt = 0; cnt < 48; cnt++){
tempbts[cnt] = key[PC_2[cnt]];
}
return 0;
}
/*循环左移*/
int DES_ROL(ElemType data[56], int time){
ElemType temp[56];
/*保存将要循环移动到右边的位*/
memcpy(temp,data,time);
memcpy(temp+time,data+28,time);
/*前28位移动*/
memcpy(data,data+time,28-time);
memcpy(data+28-time,temp,time);
/*后28位移动*/
memcpy(data+28,data+28+time,28-time);
memcpy(data+56-time,temp+time,time);
return 0;
}
/*IP置换*/
int DES_IP_Transform(ElemType data[64]){
int cnt;
ElemType temp[64];
for(cnt = 0; cnt < 64; cnt++){
temp[cnt] = data[IP_Table[cnt]];
}
memcpy(data,temp,64);
return 0;
}
/*IP逆置换*/
int DES_IP_1_Transform(ElemType data[64]){
int cnt;
ElemType temp[64];
for(cnt = 0; cnt < 64; cnt++){
temp[cnt] = data[IP_1_Table[cnt]];
}
memcpy(data,temp,64);
return 0;
}
/*扩展置换*/
int DES_E_Transform(ElemType data[48]){
int cnt;
ElemType temp[48];
for(cnt = 0; cnt < 48; cnt++){
temp[cnt] = data[E_Table[cnt]];
}
memcpy(data,temp,48);
return 0;
}
/*P置换*/
int DES_P_Transform(ElemType data[32]){
int cnt;
ElemType temp[32];
for(cnt = 0; cnt < 32; cnt++){
temp[cnt] = data[P_Table[cnt]];
}
memcpy(data,temp,32);
return 0;
}
/*异或*/
int DES_XOR(ElemType R[48], ElemType L[48] ,int count){
int cnt;
for(cnt = 0; cnt < count; cnt++){
R[cnt] ^= L[cnt];
}
return 0;
}
/*S盒置换*/
int DES_SBOX(ElemType data[48]){
int cnt;
int line,row,output;
int cur1,cur2;
for(cnt = 0; cnt < 8; cnt++){
cur1 = cnt*6;
cur2 = cnt<<2;
/*计算在S盒中的行与列*/
line = (data[cur1]<<1) + data[cur1+5];
row = (data[cur1+1]<<3) + (data[cur1+2]<<2)
+ (data[cur1+3]<<1) + data[cur1+4];
output = S[cnt][line][row];
/*化为2进制*/
data[cur2] = (output&0X08)>>3;
data[cur2+1] = (output&0X04)>>2;
data[cur2+2] = (output&0X02)>>1;
data[cur2+3] = output&0x01;
}
return 0;
}
/*交换*/
int DES_Swap(ElemType left[32], ElemType right[32]){
ElemType temp[32];
memcpy(temp,left,32);
memcpy(left,right,32);
memcpy(right,temp,32);
return 0;
}
/*加密单个分组*/
int DES_EncryptBlock(ElemType plainBlock[8], ElemType subKeys[16][48], ElemType cipherBlock[8]){
ElemType plainBits[64];
ElemType Right[48];
int cnt;
Char8ToBit64(plainBlock,plainBits);
/*初始置换(IP置换)*/
DES_IP_Transform(plainBits);
/*16轮迭代*/
for(cnt = 0; cnt < 16; cnt++){
memcpy(Right,plainBits+32,32);
/*将右半部分进行扩展置换,从32位扩展到48位*/
DES_E_Transform(Right);
/*将右半部分与子密钥进行异或操作*/
DES_XOR(Right,subKeys[cnt],48);
/*异或结果进入S盒,输出32位结果*/
DES_SBOX(Right);
/*P置换*/
DES_P_Transform(Right);
/*将明文左半部分与右半部分进行异或*/
DES_XOR(plainBits,Right,32);
if(cnt != 15){
/*最终完成左右部的交换*/
DES_Swap(plainBits,plainBits+32);
}
}
/*逆初始置换(IP^1置换)*/
DES_IP_1_Transform(plainBits);
Bit64ToChar8(plainBits,cipherBlock);
return 0;
}
/*解密单个分组*/
int DES_DecryptBlock(ElemType cipherBlock[8], ElemType subKeys[16][48],ElemType plainBlock[8]){
ElemType cipherBits[64];
ElemType Right[48];
int cnt;
Char8ToBit64(cipherBlock,cipherBits);
/*初始置换(IP置换)*/
DES_IP_Transform(cipherBits);
/*16轮迭代*/
for(cnt = 15; cnt >= 0; cnt--){
memcpy(Right,cipherBits+32,32);
/*将右半部分进行扩展置换,从32位扩展到48位*/
DES_E_Transform(Right);
/*将右半部分与子密钥进行异或操作*/
DES_XOR(Right,subKeys[cnt],48);
/*异或结果进入S盒,输出32位结果*/
DES_SBOX(Right);
/*P置换*/
DES_P_Transform(Right);
/*将明文左半部分与右半部分进行异或*/
DES_XOR(cipherBits,Right,32);
if(cnt != 0){
/*最终完成左右部的交换*/
DES_Swap(cipherBits,cipherBits+32);
}
}
/*逆初始置换(IP^1置换)*/
DES_IP_1_Transform(cipherBits);
Bit64ToChar8(cipherBits,plainBlock);
return 0;
}
/*加密文件*/
int DES_Encrypt(char *plainFile, char *keyStr,char *cipherFile){
FILE *plain,*cipher;
int count;
ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
ElemType bKey[64];
ElemType subKeys[16][48];
if((plain = fopen(plainFile,"rb")) == NULL){
return PLAIN_FILE_OPEN_ERROR;
}
if((cipher = fopen(cipherFile,"wb")) == NULL){
return CIPHER_FILE_OPEN_ERROR;
}
/*设置密钥*/
memcpy(keyBlock,keyStr,8);
/*将密钥转换为二进制流*/
Char8ToBit64(keyBlock,bKey);
/*生成子密钥*/
DES_MakeSubKeys(bKey,subKeys);
while(!feof(plain)){
/*每次读8个字节,并返回成功读取的字节数*/
if((count = fread(plainBlock,sizeof(char),8,plain)) == 8){
DES_EncryptBlock(plainBlock,subKeys,cipherBlock);
fwrite(cipherBlock,sizeof(char),8,cipher);
}
}
if(count){
/*填充*/
memset(plainBlock + count,'\0',7 - count);
/*最后一个字符保存包括最后一个字符在内的所填充的字符数量*/
plainBlock[7] = 8 - count;
DES_EncryptBlock(plainBlock,subKeys,cipherBlock);
fwrite(cipherBlock,sizeof(char),8,cipher);
}
fclose(plain);
fclose(cipher);
return OK;
}
/*解密文件*/
int DES_Decrypt(char *cipherFile, char *keyStr,char *plainFile){
FILE *plain, *cipher;
int count,times = 0;
long fileLen;
ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
ElemType bKey[64];
ElemType subKeys[16][48];
if((cipher = fopen(cipherFile,"rb")) == NULL){
return CIPHER_FILE_OPEN_ERROR;
}
if((plain = fopen(plainFile,"wb")) == NULL){
return PLAIN_FILE_OPEN_ERROR;
}
/*设置密钥*/
memcpy(keyBlock,keyStr,8);
/*将密钥转换为二进制流*/
Char8ToBit64(keyBlock,bKey);
/*生成子密钥*/
DES_MakeSubKeys(bKey,subKeys);
/*取文件长度 */
fseek(cipher,0,SEEK_END);/*将文件指针置尾*/
fileLen = ftell(cipher); /*取文件指针当前位置*/
rewind(cipher); /*将文件指针重指向文件头*/
while(1){
/*密文的字节数一定是8的整数倍*/
fread(cipherBlock,sizeof(char),8,cipher);
DES_DecryptBlock(cipherBlock,subKeys,plainBlock);
times += 8;
if(times < fileLen){
fwrite(plainBlock,sizeof(char),8,plain);
}
else{
break;
}
}
/*判断末尾是否被填充*/
if(plainBlock[7] < 8){
for(count = 8 - plainBlock[7]; count < 7; count++){
if(plainBlock[count] != '\0'){
break;
}
}
}
if(count == 7){/*有填充*/
fwrite(plainBlock,sizeof(char),8 - plainBlock[7],plain);
}
else{/*无填充*/
fwrite(plainBlock,sizeof(char),8,plain);
}
fclose(plain);
fclose(cipher);
return OK;
}
int main()
{
clock_t a,b;
a = clock();
DES_Encrypt("1.txt","key.txt","2.txt");
b = clock();
printf("加密消耗%d毫秒\n",b-a);
system("pause");
a = clock();
DES_Decrypt("2.txt","key.txt","3.txt");
b = clock();
printf("解密消耗%d毫秒\n",b-a);
getchar();
return 0;
}
F. C语言已知解密算法求加密算法
以下是加密算法
voidPasswdencode(char*outstr,char*instr)
{
intinstr_len=strlen(instr);
intoutstr_len=0;
inti=0;
for(i=0;i<instr_len;i++)
{
outstr[outstr_len++]=(instr[i]&0x0F)+'m';
outstr[outstr_len++]=((instr[i]>>4)&0x0F)+'m';
}
outstr[outstr_len]='