//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;
}
//解析文件成字符串
//file -> str
int DES_Decrypt_file_to_str(char *cipherFile, char *keyStr,char *result)
{
int cipher;
int count,times = 0;
long fileLen;
ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
ElemType bKey[64];
ElemType subKeys[16][48];
if((cipher = open(cipherFile,O_RDONLY)) < 0){
return CIPHER_FILE_OPEN_ERROR;
}
printf("cipher = %d\n",cipher);
//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
fileLen = lseek(cipher,0,SEEK_END); //将文件指针置尾 取文件指针当前位置
lseek(cipher,0,SEEK_SET); //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
read(cipher,cipherBlock,sizeof(cipherBlock));
DES_DecryptBlock(cipherBlock,subKeys,plainBlock);
if(times < fileLen){
memcpy(result + times,plainBlock,8);
times += 8;
//printf("result = %s\n",result);
}
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
memcpy(result + times,plainBlock,8 - plainBlock[7]);
}
else{//无填充
memcpy(result + times,plainBlock,8);
}
close(cipher);
return OK;
}
//解密文件
unsigned char DES_Decrypt(unsigned char *keyStr,unsigned char *cipherFile,unsigned char *plainFile)
{
// unsigned char plainBlock[8],cipherBlock[8],
unsigned char bKey[64],keyBlock[8],subKeys[16][48];
memcpy(keyBlock,keyStr,8); //设置密钥
Char8ToBit64(keyBlock,bKey); //将密钥转换为二进制流
DES_MakeSubKeys(bKey,subKeys); //生成子密钥
DES_DecryptBlock(cipherFile,subKeys,plainFile);
return 1;
}
//解密文件
int DES_Decrypt(const char *pSrcData, int &nLen, const char *keyStr,char *pDesData){
int count,times = 0;
ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
ElemType bKey[64];
ElemType subKeys[16][48];
//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(times<nLen){
//密文的字节数一定是8的整数倍
memcpy(cipherBlock,pSrcData+times,8);
DES_DecryptBlock(cipherBlock,subKeys,plainBlock);
memcpy(pDesData+times,plainBlock,8);
times += 8;
}
//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
times = times - plainBlock[7];
}
nLen = times;
return OK;
}
/*解密文件 author by yx */
int DES_Decrypt(unsigned char *cipherbuf,unsigned char *keyStr,unsigned char *plainbuf, unsigned long Num_len)
{
long fileLen;
ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
ElemType bKey[64];
ElemType subKeys[16][48];
int count,times = 0;
unsigned char *TempBufIn=NULL;
unsigned char *TempBufOut=NULL;
if(cipherbuf == NULL||keyStr==NULL||plainbuf==NULL||Num_len==0)
return -1;
TempBufIn=cipherbuf;
TempBufOut=plainbuf;
/*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(1)
{
/*密文的字节数一定是8的整数倍*/
memset(cipherBlock,0,8);
memset(plainBlock,0,8);
//读取缓冲区数据
memcpy(cipherBlock,TempBufIn,8);
TempBufIn+=8;
DES_DecryptBlock(cipherBlock,subKeys,plainBlock);
times += 8;
if(times < Num_len)
{
//将解密后的数据写回缓冲区；
memset(TempBufOut,0,8);
memcpy(TempBufOut,plainBlock,8);
TempBufOut+=8;
}
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*/
memset(TempBufOut,0,8);
memcpy(TempBufOut,plainBlock,8 - plainBlock[7]);
}
else
{/*无填充*/
memset(TempBufOut,0,8);
memcpy(TempBufOut,plainBlock,8);
}
return OK;
}
//字符串解密
int DES_Decrypt_str(char *source,char *keyStr,char *reslut)
{
int count = 0,times = 0;
long fileLen = 178;
printf("fileLen = %ld\n",fileLen);
ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
ElemType bKey[64];
ElemType subKeys[16][48];
//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);
//加载解密数据
while(times < fileLen){
memset(cipherBlock,'\0',8);
memcpy(plainBlock,source+times,8);
for(int i = 0;i<8;++i)
printf("times = %d cipherBlock[%d] = %x\n",times,i,plainBlock[i]);
DES_DecryptBlock(plainBlock,subKeys,cipherBlock);
printf("times = %d cipherBlock = ",times);
for(int i = 0; i < 8;++i)
printf("%x ",cipherBlock[i]);
printf("\n");
memcpy(reslut+times,cipherBlock,8);
printf("reslut = %s\n",reslut);
times += 8;
}
printf("times = %d cipherBlock = ",times);
for(int i = 0; i < 8;++i)
printf("%x ",cipherBlock[i]);
printf("\n");
//判断末尾是否被填充
if(cipherBlock[7] < 8){
printf("for cipherBlock = %s\n",cipherBlock);
printf("for count = %d\n",8 - cipherBlock[7]);
for(count = 8 - cipherBlock[7]; count < 7; count++){ // 4 5 6 7
if(cipherBlock[count] != '\0'){
break;
}
}
}
if(count == 7){//有填充
memcpy(reslut+times,cipherBlock,8 - cipherBlock[7]);
printf("if cipherBlock = %s\n",reslut+times);
}
else{//无填充
memcpy(reslut+times,cipherBlock,8);
printf("else cipherBlock = %s\n",reslut+times);
}
printf("cipherBlock = %s\n",reslut);
for(int i = 0; i < 184;++i)
printf("%x ",reslut[i]);
printf("\n");
return 0;
}
