C++中四种加密算法之DES源代码
DES算法是一种最通用的对称密钥算法，因为算法本身是公开的，所以其安全性在于密钥的安全性。基于密钥的算法通常有两类：对称算法和公开密钥算法。对称算法的对称性体现在加密密钥能够从解密密钥推算出来，反之亦然。
在大多数对称算法中，加解密的密钥是相同的，DES就是这样。可见，对称密钥算法的加解密密钥都是保密的。而公开密钥算法的加密密钥是公开的，解密密钥是保密的。
DES具体算法如下：
//////////////////////////////////////////////////////////////////////////
/*
Providedby朱孟斌,NationalUniversityOfTechnology
Email:zmbtsubasa@gmailcom
Thisproductisfreeforuse
*/
//////////////////////////////////////////////////////////////////////////
#ifndefDes_H
#defineDes_H
//!enumbool{false,true};
/*!
ifboolisnotsupported,usethisorjustreplacewithcharanduse1fortrue,0forfalse;
@seeenum{ENCRYPT,DECRYPT};
*/
enum{ENCRYPT,DECRYPT};
/*@brief16圈子密钥*/
staticboolSubKey[2][16][48];//16圈子密钥
/*@brief3次DES标志*/
staticboolIs3DES;//3次DES标志
staticcharTmp[256];
staticchardeskey[16];
typedefbool(*PSubKey)[16][48];
class_declspec(dllexport)Des
{
public:
Des();
~Des();
//!Type—ENCRYPT:加密,DECRYPT:解密
/*!
输出缓冲区(Out)的长度>=((datalen+7)/8)*8,即比datalen大的且是8的倍数的最小正整数
In可以=Out,此时加/解密后将覆盖输入缓冲区(In)的内容
当keylen>8时系统自动使用3次DES加/解密,否则使用标准DES加/解密超过16字节后只取前16字节
@seeboolDes_Go(char*Out,char*In,longdatalen,constchar*Key,intkeylen,boolType=ENCRYPT);
*/
boolDes_Go(char*Out,char*In,longdatalen,constchar*Key,intkeylen,boolType=ENCRYPT);
private:
/*!@brief标准DES加/解密
@seestaticvoidDES(charOut[8],charIn[8],constPSubKeypSubKey,boolType);
*/
staticvoidDES(charOut[8],charIn[8],constPSubKeypSubKey,boolType);//标准DES加/解密
/*!@brief设置密钥
@seestaticvoidSetKey(constchar*Key,intlen);
*/
staticvoidSetKey(constchar*Key,intlen);//设置密钥
/*!@brief设置子密钥
@seestaticvoidSetSubKey(PSubKeypSubKey,constcharKey[8]);
*/
staticvoidSetSubKey(PSubKeypSubKey,constcharKey[8]);//设置子密钥
/*!@brieff函数
@seestaticvoidF_func(boolIn[32],constboolKi[48]);
*/
staticvoidF_func(boolIn[32],constboolKi[48]);//f函数
/*!@briefS盒代替
@seestaticvoidS_func(boolOut[32],constboolIn[48]);
*/
staticvoidS_func(boolOut[32],constboolIn[48]);//S盒代替
/*!@brief变换
@seestaticvoidTransform(bool*Out,bool*In,constchar*Table,intlen);
*/
staticvoidTransform(bool*Out,bool*In,constchar*Table,intlen);//变换
/*!@brief异或
@seestaticvoidXor(bool*InA,constbool*InB,intlen);
*/
staticvoidXor(bool*InA,constbool*InB,intlen);//异或
/*!@brief循环左移
@seestaticvoidRotateL(bool*In,intlen,intloop);
*/
staticvoidRotateL(bool*In,intlen,intloop);//循环左移
/*!@brief字节组转换成位组
@seestaticvoidByteToBit(bool*Out,constchar*In,intbits);
*/
staticvoidByteToBit(bool*Out,constchar*In,intbits);//字节组转换成位组
/*!@brief位组转换成字节组
@seestaticvoidBitToByte(char*Out,constbool*In,intbits);
*/
staticvoidBitToByte(char*Out,constbool*In,intbits);//位组转换成字节组
};
//////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
#endif
DES.cpp文件：
//////////////////////////////////////////////////////////////////////////
/*
Providedby朱孟斌,NationalUniversityOfTechnology
Email:zmbtsubasa@gmailcom
Thisproductisfreeforuse
*/
//////////////////////////////////////////////////////////////////////////
#include"memoryh"
#include"Desh"
//////////////////////////////////////////////////////////////////////////
//initialpermutationIP
conststaticcharIP_Table[64]={
58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4,
62,54,46,38,30,22,14,6,64,56,48,40,32,24,16,8,
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
};
//finalpermutationIP^-1
conststaticcharIPR_Table[64]={
40,8,48,16,56,24,64,32,39,7,47,15,55,23,63,31,
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
};
//expansionoperationmatrix
staticconstcharE_Table[48]={
32,1,2,3,4,5,4,5,6,7,8,9,
8,9,10,11,12,13,12,13,14,15,16,17,
16,17,18,19,20,21,20,21,22,23,24,25,
24,25,26,27,28,29,28,29,30,31,32,1
};
//32-bitpermutationfunctionPusedontheoutputoftheS-boxes
conststaticcharP_Table[32]={
16,7,20,21,29,12,28,17,1,15,23,26,5,18,31,10,
2,8,24,14,32,27,3,9,19,13,30,6,22,11,4,25
};
//permutedchoicetable(key)
conststaticcharPC1_Table[56]={
57,49,41,33,25,17,9,1,58,50,42,34,26,18,
10,2,59,51,43,35,27,19,11,3,60,52,44,36,
63,55,47,39,31,23,15,7,62,54,46,38,30,22,
14,6,61,53,45,37,29,21,13,5,28,20,12,4
};
//permutedchoicekey(table)
conststaticcharPC2_Table[48]={
14,17,11,24,1,5,3,28,15,6,21,10,
23,19,12,4,26,8,16,7,27,20,13,2,
41,52,31,37,47,55,30,40,51,45,33,48,
44,49,39,56,34,53,46,42,50,36,29,32
};
//numberleftrotationsofpc1
conststaticcharLOOP_Table[16]={
1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};
//The(in)famousS-boxes
conststaticcharS_Box[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
};
//////////////////////////////////////////////////////////////////////////
//Codestarts:
//////////////////////////////////////////////////////////////////////////
Des::Des()
{
}
Des::~Des()
{
}
boolDes::Des_Go(char*Out,char*In,longdatalen,constchar*Key,intkeylen,boolType)
{
if(!(Out&&In&&Key&&(datalen=(datalen+7)&0xfffffff8)))
returnfalse;
SetKey(Key,keylen);
if(!Is3DES){//1次DES
for(longi=0,j=datalen>>3;i<j;++i,Out+=8,In+=8)
DES(Out,In,&SubKey[0],Type);
}else{//3次DES加密:加(key0)-解(key1)-加(key0)解密::解(key0)-加(key1)-解(key0)
for(longi=0,j=datalen>>3;i<j;++i,Out+=8,In+=8){
DES(Out,In,&SubKey[0],Type);
DES(Out,Out,&SubKey[1],!Type);
DES(Out,Out,&SubKey[0],Type);
}
}
returntrue;
}
voidDes::SetKey(constchar*Key,intlen)
{
memset(deskey,0,16);
memcpy(deskey,Key,len>16?16:len);
SetSubKey(&SubKey[0],&deskey[0]);
Is3DES=len>8?(SetSubKey(&SubKey[1],&deskey[8]),true):false;
}
voidDes::DES(charOut[8],charIn[8],constPSubKeypSubKey,boolType)
{
staticboolM[64],tmp[32],*Li=&M[0],*Ri=&M[32];
ByteToBit(M,In,64);
Transform(M,M,IP_Table,64);
if(Type==ENCRYPT){
for(inti=0;i<16;++i){
memcpy(tmp,Ri,32);
F_func(Ri,(*pSubKey)[i]);
Xor(Ri,Li,32);
memcpy(Li,tmp,32);
}
}else{
for(inti=15;i>=0;--i){
memcpy(tmp,Li,32);
F_func(Li,(*pSubKey)[i]);
Xor(Li,Ri,32);
memcpy(Ri,tmp,32);
}
}
Transform(M,M,IPR_Table,64);
BitToByte(Out,M,64);
}
voidDes::SetSubKey(PSubKeypSubKey,constcharKey[8])
{
staticboolK[64],*KL=&K[0],*KR=&K[28];
ByteToBit(K,Key,64);
Transform(K,K,PC1_Table,56);
for(inti=0;i<16;++i){
RotateL(KL,28,LOOP_Table[i]);
RotateL(KR,28,LOOP_Table[i]);
Transform((*pSubKey)[i],K,PC2_Table,48);
}
}
voidDes::F_func(boolIn[32],constboolKi[48])
{
staticboolMR[48];
Transform(MR,In,E_Table,48);
Xor(MR,Ki,48);
S_func(In,MR);
Transform(In,In,P_Table,32);
}
voidDes::S_func(boolOut[32],constboolIn[48])
{
for(chari=0,j,k;i<8;++i,In+=6,Out+=4){
j=(In[0]<<1)+In[5];
k=(In[1]<<3)+(In[2]<<2)+(In[3]<<1)+In[4];
ByteToBit(Out,&S_Box[i][j][k],4);
}
}
voidDes::Transform(bool*Out,bool*In,constchar*Table,intlen)
{
for(inti=0;i<len;++i)
Tmp[i]=In[Table[i]-1];
memcpy(Out,Tmp,len);
}
voidDes::Xor(bool*InA,constbool*InB,intlen)
{
for(inti=0;i<len;++i)
InA[i]^=InB[i];
}
voidDes::RotateL(bool*In,intlen,intloop)
{
memcpy(Tmp,In,loop);
memcpy(In,In+loop,len-loop);
memcpy(In+len-loop,Tmp,loop);
}
voidDes::ByteToBit(bool*Out,constchar*In,intbits)
{
for(inti=0;i<bits;++i)
Out[i]=(In[i>>3]>>(i&7))&1;
}
voidDes::BitToByte(char*Out,constbool*In,intbits)
{
memset(Out,0,bits>>3);
for(inti=0;i<bits;++i)
Out[i>>3]|=In[i]<<(i&7);
}
//////////////////////////////////////////////////////////////////////////
//Codeends
//////////////////////////////////////////////////////////////////////////
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