第一次发帖，申请邀请码文章，当然版主大发慈悲，给个精华鼓励新人发帖就更好了。
想学习下DES得算法。网上找来的。C语言代码，按照那份代码用汇编重写了下。
另附上一个简单的Demo和原来C语言的代码。
原来C语言的文件里注释的很详细所以我就没多做注释了。函数名，变量啥的我基本没变，大家对着C的源文件里的注释应该很容易看懂。
Demo效果 如下图：
加密
解密
代码:
;-------------------------------------------------------------------------------- ; ;File: DES.asm ;Author: Sin ;Date: 2011.9.20 ; ;-------------------------------------------------------------------------------- .386 .model flat,stdcall option casemap:none ByteToBit proto :BYTE,:DWORD BitToByte proto :DWORD,:DWORD Char8ToBit64 proto :DWORD,:DWORD Bit64ToChar8 proto :DWORD,:DWORD Bit64ToChar64 PROTO :DWORD,:DWORD Char64ToBit64 PROTO :DWORD,:DWORD DES_MakeSubKeys proto :DWORD,:DWORD DES_PC1_Transform proto :DWORD,:DWORD DES_PC2_Transform proto :DWORD,:DWORD DES_ROL proto :DWORD,:DWORD DES_IP_Transform proto :DWORD DES_IP_1_Transform proto :DWORD DES_E_Transform proto :DWORD DES_P_Transform proto :DWORD DES_SBOX proto :DWORD DES_XOR proto :DWORD,:DWORD,:DWORD DES_Swap proto :DWORD,:DWORD DES_EncryptBlock proto :DWORD,:DWORD,:DWORD DES_DecryptBlock proto :DWORD,:DWORD,:DWORD DES_Encrypt proto :DWORD,:DWORD,:DWORD,:DWORD DES_Decrypt proto :DWORD,:DWORD,:DWORD,:DWORD .data align 4 ;IP_Table[0] ~ IP_Table[63] IP_Table dd 57,49,41,33,25,17,9,1 dd 59,51,43,35,27,19,11,3 dd 61,53,45,37,29,21,13,5 dd 63,55,47,39,31,23,15,7 dd 56,48,40,32,24,16,8,0 dd 58,50,42,34,26,18,10,2 dd 60,52,44,36,28,20,12,4 dd 62,54,46,38,30,22,14,6 ;IP_1_Table[0] ~ IP_1_Table[63] IP_1_Table dd 39,7,47,15,55,23,63,31 dd 38,6,46,14,54,22,62,30 dd 37,5,45,13,53,21,61,29 dd 36,4,44,12,52,20,60,28 dd 35,3,43,11,51,19,59,27 dd 34,2,42,10,50,18,58,26 dd 33,1,41,9,49,17,57,25 dd 32,0,40,8,48,16,56,24 E_Table dd 31,0,1,2,3,4 dd 3,4,5,6,7,8 dd 7,8,9,10,11,12 dd 11,12,13,14,15,16 dd 15,16,17,18,19,20 dd 19,20,21,22,23,24 dd 23,24,25,26,27,28 dd 27,28,29,30,31,0 P_Table dd 15,6,19,20,28,11,27,16 dd 0,14,22,25,4,17,30,9 dd 1,7,23,13,31,26,2,8 dd 18,12,29,5,21,10,3,24 ; S[0][0][0] ~ S[0][3][15] S dd 14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7 dd 0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8 dd 4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0 dd 15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13 ;S[1][0][0] ~ S[1][3][15] dd 15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10 dd 3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5 dd 0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15 dd 13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9 ; dd 10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8 dd 13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1 dd 13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7 dd 1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12 ; dd 7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15 dd 13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9 dd 10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4 dd 3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14 ; dd 2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9 dd 14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6 dd 4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14 dd 11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3 ; dd 12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11 dd 10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8 dd 9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6 dd 4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13 ; dd 4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1 dd 13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6 dd 1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2 dd 6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12 ; dd 13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7 dd 1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2 dd 7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8 dd 2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11 PC_1 dd 56,48,40,32,24,16,8 dd 0,57,49,41,33,25,17 dd 9,1,58,50,42,34,26 dd 18,10,2,59,51,43,35 dd 62,54,46,38,30,22,14 dd 6,61,53,45,37,29,21 dd 13,5,60,52,44,36,28 dd 20,12,4,27,19,11,3 PC_2 dd 13,16,10,23,0,4,2,27 dd 14,5,20,9,22,18,11,3 dd 25,7,15,6,26,19,12,1 dd 40,51,30,36,46,54,29,39 dd 50,44,32,46,43,48,38,55 dd 33,52,45,41,49,35,28,31 MOVE_TIMES dd 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1 .data? align 4 .code memcpy proc uses esi edi ecx dst:DWORD,src:DWORD,len:DWORD pushfd cld mov edi,dst mov esi,src mov ecx,len rep movsb xor eax,eax popfd ret memcpy endp ByteToBit proc uses edi ecx edx cb:BYTE,bit:DWORD pushfd cld mov ecx,8 mov edi,bit mov dl,cb xor eax,eax @@: shr dl,1 setc al stosb dec ecx jnz @b popfd xor eax,eax ret ByteToBit endp BitToByte proc uses esi ecx edx bit:DWORD,cb:DWORD pushfd cld xor ecx,ecx xor edx,edx xor eax,eax mov esi,bit @@: lodsb shl al,cl or dl,al inc cl cmp cl,8 jnz @b mov eax,cb mov BYTE PTR [eax],dl xor eax,eax popfd ret BitToByte endp Char8ToBit64 proc uses esi ebx ecx edx cb:DWORD,bit:DWORD pushfd cld mov esi,cb xor eax,eax xor ecx,ecx xor edx,edx @@: lodsb mov edx,ecx shl edx,3 mov ebx,bit add ebx,edx invoke ByteToBit,al,ebx inc ecx cmp ecx,8 jnz @b xor eax,eax popfd ret Char8ToBit64 endp Bit64ToChar8 proc uses esi edi ecx bit:DWORD,cb:DWORD pushfd cld mov edi,cb mov ecx,8 xor eax,eax rep stosb mov esi,bit mov edi,cb xor eax,eax xor ecx,ecx @@: mov eax,ecx shl eax,3 mov esi,bit add esi,eax mov edi,cb add edi,ecx invoke BitToByte,esi,edi inc ecx cmp ecx,8 jnz @b xor eax,eax popfd ret Bit64ToChar8 endp Bit64ToChar64 proc uses esi edi ecx lpInString,lpOutString pushfd cld mov esi,lpInString mov edi,lpOutString xor eax,eax mov ecx,64 @@: lodsb add al,30H stosb dec ecx jnz @b popfd xor eax,eax ret Bit64ToChar64 endp Char64ToBit64 proc uses esi edi ecx lpInstring,lpOutString pushfd cld mov esi,lpInstring mov edi,lpOutString xor eax,eax mov ecx,64 @@: lodsb sub al,30H stosb dec ecx jnz @b popfd xor eax,eax ret Char64ToBit64 endp DES_MakeSubKeys proc uses ecx edx ebx key:DWORD,subkeys:DWORD LOCAL temp[56]:BYTE invoke DES_PC1_Transform,key,addr temp xor ecx,ecx mov edx,offset MOVE_TIMES mov ebx,subkeys @@: mov eax,[edx+ecx*4] push eax lea eax,temp push eax call DES_ROL mov eax,ecx imul eax,48 add eax,ebx push eax push key call DES_PC2_Transform inc ecx cmp ecx,16 jnz @b xor eax,eax ret DES_MakeSubKeys endp DES_PC1_Transform proc uses edi ebx ecx edx key:DWORD,tempbits:DWORD pushfd cld mov edi,tempbits mov ebx,key mov edx,offset PC_1 xor ecx,ecx @@: mov eax,[edx+ecx*4] mov al,BYTE PTR [ebx+eax] stosb inc ecx cmp ecx,56 jnz @b xor eax,eax popfd ret DES_PC1_Transform endp DES_PC2_Transform proc uses edi ebx ecx edx key:DWORD,tempbits:DWORD pushfd cld mov edi,tempbits mov ebx,key mov edx,offset PC_2 xor ecx,ecx @@: mov eax,[edx+ecx*4] mov al,BYTE PTR [ebx+eax] stosb inc ecx cmp ecx,48 jnz @b xor eax,eax popfd ret DES_PC2_Transform endp DES_ROL proc uses edx ecx ebx data:DWORD,time:DWORD LOCAL temp[56]:BYTE lea ebx,temp mov edx,data mov ecx,time push ecx push edx push ebx call memcpy push ecx mov eax,edx add eax,28 push eax mov eax,ebx add eax,ecx push eax call memcpy mov eax,28 sub eax,ecx push eax mov eax,edx add eax,ecx push eax push edx call memcpy push ecx push ebx mov eax,edx add eax,28 sub eax,ecx push eax call memcpy mov eax,28 sub eax,ecx push eax mov eax,edx add eax,28 add eax,ecx push eax mov eax,edx add eax,28 push eax call memcpy push ecx mov eax,ebx add eax,ecx push eax mov eax,edx add eax,56 sub eax,ecx push eax call memcpy xor eax,eax ret DES_ROL endp DES_IP_Transform proc uses edi ebx ecx edx data:DWORD LOCAL temp[64]:BYTE pushfd cld lea edi,temp mov edx,offset IP_Table mov ebx,data xor ecx,ecx @@: mov eax,[edx+ecx*4] mov al,BYTE PTR [ebx+eax] stosb inc ecx cmp ecx,64 jnz @b invoke memcpy,data,addr temp,64 xor eax,eax popfd ret DES_IP_Transform endp DES_IP_1_Transform proc uses edi ebx ecx edx data:DWORD LOCAL temp[64]:BYTE pushfd cld lea edi,temp mov edx,offset IP_1_Table mov ebx,data xor ecx,ecx @@: mov eax,[edx+ecx*4] mov al,BYTE PTR [ebx+eax] stosb inc ecx cmp ecx,64 jnz @b invoke memcpy,data,addr temp,64 xor eax,eax popfd ret DES_IP_1_Transform endp DES_E_Transform proc uses edi ebx ecx edx data:DWORD LOCAL temp[48]:BYTE pushfd cld lea edi,temp mov edx,offset E_Table mov ebx,data xor ecx,ecx @@: mov eax,[edx+ecx*4] mov al,BYTE PTR [ebx+eax] stosb inc ecx cmp ecx,48 jnz @b invoke memcpy,data,addr temp,48 xor eax,eax popfd ret DES_E_Transform endp DES_P_Transform proc uses edi ebx ecx edx data:DWORD LOCAL temp[32]:BYTE pushfd cld lea edi,temp mov edx,offset P_Table mov ebx,data xor ecx,ecx @@: mov eax,[edx+ecx*4] mov al,BYTE PTR [ebx+eax] stosb inc ecx cmp ecx,32 jnz @b invoke memcpy,data,addr temp,32 xor eax,eax popfd ret DES_P_Transform endp DES_XOR proc uses esi edi ecx edx R:DWORD,L:DWORD,count:DWORD mov edi,R mov esi,L xor eax,eax xor edx,edx xor ecx,ecx @@: cmp ecx,count jz @Ret mov al,BYTE PTR [esi+ecx] mov dl,BYTE PTR [edi+ecx] xor al,dl inc ecx jmp @b @Ret: xor eax,eax ret DES_XOR endp DES_SBOX proc uses esi edi ebx ecx edx data:DWORD LOCAL _line:DWORD,row:DWORD,output:DWORD ; LOCAL cur1:DWORD,cur2:DWORD ; use cur1-> esi cur2->edi mov ebx,data xor ecx,ecx @@: mov esi,ecx imul esi,6 mov edi,ecx shl edi,2 mov al,BYTE PTR [ebx+esi] shl al,1 movzx edx,al mov al,BYTE PTR [ebx+esi+5] movzx eax,al add eax,edx mov _line,eax mov al,BYTE PTR [ebx+esi+1] shl al,3 movzx edx,al mov al,BYTE PTR [ebx+esi+2] shl al,2 movzx eax,al add edx,eax mov al,BYTE PTR [ebx+esi+3] shl al,1 movzx eax,al add edx,eax mov al,BYTE PTR [ebx+esi+4] movzx eax,al add eax,edx mov row,eax mov edx,offset S mov eax,_line imul eax,row imul eax,ecx mov eax,DWORD PTR [edx+eax] mov output,eax and eax,08H shr eax,3 mov BYTE PTR [ebx+edi],al mov eax,output and eax,04H shr eax,2 mov BYTE PTR [ebx+edi+1],al mov eax,output and eax,02H shr eax,1 mov BYTE PTR [ebx+edi+2],al mov eax,output and eax,01H mov BYTE PTR [ebx+edi+3],al inc ecx cmp ecx,8 jnz @b xor eax,eax ret DES_SBOX endp DES_Swap proc left:DWORD,right:DWORD LOCAL temp[32]:BYTE invoke memcpy,addr temp,left,32 invoke memcpy,left,right,32 invoke memcpy,right,addr temp,32 xor eax,eax ret DES_Swap endp DES_EncryptBlock proc uses ecx edx plainBlock:DWORD,subKeys:DWORD,cipherBlock:DWORD LOCAL plainBits[64]:BYTE LOCAL copyRight[48]:BYTE invoke Char8ToBit64,plainBlock,addr plainBits invoke DES_IP_Transform,addr plainBits xor ecx,ecx @loop: push 32 lea eax,plainBits add eax,32 push eax lea eax,copyRight push eax call memcpy invoke DES_E_Transform,addr copyRight mov eax,subKeys mov edx,ecx imul edx,48 add eax,edx invoke DES_XOR,addr copyRight,eax,48 invoke DES_SBOX,addr copyRight invoke DES_P_Transform,addr copyRight invoke DES_XOR,addr plainBits,addr copyRight,32 cmp ecx,15 jz @f lea eax,plainBits add eax,32 invoke DES_Swap,addr plainBits,eax @@: inc ecx cmp ecx,16 jnz @loop invoke DES_IP_1_Transform,addr plainBits invoke Bit64ToChar8,addr plainBits,cipherBlock xor eax,eax ret DES_EncryptBlock endp DES_DecryptBlock proc uses edx ecx cipherBlock:DWORD,subKeys:DWORD,plainBlock:DWORD LOCAL cipherBits[64]:BYTE LOCAL copyRight[48]:BYTE invoke Char8ToBit64,cipherBlock,addr cipherBits invoke DES_IP_Transform,addr cipherBits mov ecx,15 @loop: push 32 lea eax,cipherBits add eax,32 push eax lea eax,copyRight push eax call memcpy invoke DES_E_Transform,addr copyRight mov edx,subKeys mov eax,ecx imul eax,48 add eax,edx invoke DES_XOR,addr copyRight,eax,48 invoke DES_SBOX,addr copyRight invoke DES_P_Transform,addr copyRight invoke DES_XOR,addr cipherBits,addr copyRight,32 test ecx,ecx jz @f lea eax,cipherBits add eax,32 invoke DES_Swap,addr cipherBits,eax @@: dec ecx cmp ecx,0 jge @loop invoke DES_IP_1_Transform,addr cipherBits invoke Bit64ToChar8,addr cipherBits,plainBlock xor eax,eax ret DES_DecryptBlock endp DES_Encrypt proc uses esi edi edx ecx lpInString,cbInString,lpKeyString,lpOutString local szSubKeys[768]:BYTE ;16*48 local bKey[64]:BYTE local szTemp[8]:BYTE local szResult[8]:BYTE invoke Char8ToBit64,lpKeyString,addr bKey invoke DES_MakeSubKeys,addr bKey,addr szSubKeys mov ecx,cbInString mov esi,lpInString mov edi,lpOutString xor edx,edx @loop: cmp ecx,8 jb @f invoke memcpy,addr szTemp,esi,8 add esi,8 invoke DES_EncryptBlock,addr szTemp,addr szSubKeys,addr szResult jmp @copy @@: invoke memcpy,addr szTemp,esi,ecx pushfd cld push edi lea edi,szTemp add edi,ecx mov eax,7 sub eax,ecx mov BYTE PTR [edi+7],al mov ecx,eax xor eax,eax rep stosb pop edi popfd invoke DES_EncryptBlock,addr szTemp,addr szSubKeys,addr szResult @copy: invoke memcpy,edi,addr szResult,8 add edi,8 add edx,8 sub ecx,8 jg @loop mov eax,edx ret DES_Encrypt endp DES_Decrypt proc uses esi edi ebx ecx edx lpInString,cbInString,lpKeyString,lpOutString local szSubKeys[768]:BYTE local bKey[64]:BYTE local szResult[8]:BYTE invoke Char8ToBit64,lpKeyString,addr bKey invoke DES_MakeSubKeys,addr bKey,addr szSubKeys mov ecx,cbInString mov esi,lpInString mov edi,lpOutString xor ebx,ebx @@: cmp ecx,0 jbe @Ret invoke DES_DecryptBlock,esi,addr szSubKeys,addr szResult add esi,8 invoke memcpy,edi,addr szResult,8 add edi,8 add ebx,8 sub ecx,8 test ecx,ecx jz @loop jmp @b @loop: pushfd cld push esi lea esi,szResult xor eax,eax mov al,BYTE PTR [esi+7] cmp al,8 jae @Ret ;>=8 跳出 movzx eax,al mov ecx,8 sub ecx,eax ; mov edx,ecx @@: lodsb test al,al jnz @f ;有不为0的跳出 inc ecx cmp ecx,7 jb @b push edx lea eax,szResult push eax sub edi,8 push edi call memcpy add ebx,edx sub ebx,8 @@: pop esi popfd @Ret: mov eax,ebx ret DES_Decrypt endp end