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Delphi AES加密

2018-10-31

(**************************************************************)
(*    Advanced Encryption Standard (AES)    *)
(*    Interface Unit v1.3    *)
(*    *)
(*    Copyright (c) 2002 Jorlen Young    *)
(*    *)
(* 说明：    *)
(*    基于 ElASE.pas 单元封装    *)
(*    *)
(*    这是一个 AES 加密算法的标准接口。    *)
(* 调用示例：    *)
(* if not EncryptStream(src, key, TStream(Dest), keybit) then *)
(* showmessage('encrypt error');    *)
(*    *)
(* if not DecryptStream(src, key, TStream(Dest), keybit) then *)
(* showmessage('encrypt error');    *)
(*    *)
(* *** 一定要对Dest进行TStream(Dest) ***    *)
(* ========================================================== *)
(*    *)
(* 支持 128 / 192 / 256 位的密匙    *)
(* 默认情况下按照 128 位密匙操作    *)
(*    *)
(**************************************************************)

unit AES;

interface

{$IFDEF VER210}
{$WARN IMPLICIT_STRING_CAST OFF} //关闭警告
{$WARN IMPLICIT_STRING_CAST_LOSS OFF}
{$ENDIF}
uses
SysUtils, Classes, Math, ElAES;

const
SDestStreamNotCreated = 'Dest stream not created.';
SEncryptStreamError = 'Encrypt stream error.';
SDecryptStreamError = 'Decrypt stream error.';

type
TKeyBit = (kb128, kb192, kb256);

function StrToHex(Const str: AnsiString): AnsiString;
function HexToStr(const Str: AnsiString): AnsiString;

function EncryptString(Value: AnsiString; Key: AnsiString;
KeyBit: TKeyBit = kb128): AnsiString;
function DecryptString(Value: AnsiString; Key: AnsiString;
KeyBit: TKeyBit = kb128): AnsiString;

function EncryptStream(Src: TStream; Key: AnsiString;
var Dest: TStream; KeyBit: TKeyBit = kb128): Boolean;
function DecryptStream(Src: TStream; Key: AnsiString;
var Dest: TStream; KeyBit: TKeyBit = kb128): Boolean;

procedure EncryptFile(SourceFile, DestFile: String;
Key: AnsiString; KeyBit: TKeyBit = kb128);
procedure DecryptFile(SourceFile, DestFile: String;
Key: AnsiString; KeyBit: TKeyBit = kb128);

implementation

function StrToHex(Const str: Ansistring): Ansistring;
asm
   push ebx
   push esi
   push edi
   test eax,eax
   jz @@Exit
   mov esi,edx    //保存edx值，用来产生新字符串的地址
   mov edi,eax    //保存原字符串
   mov edx,[eax-4] //获得字符串长度
   test edx,edx    //检查长度
   je @@Exit    {Length(S) = 0}
   mov ecx,edx    //保存长度
   Push ecx
   shl edx,1
   mov eax,esi
   {$IFDEF VER210}
   movzx ecx, word ptr [edi-12] {需要设置CodePage}
   {$ENDIF}
   call System.@LStrSetLength //设置新串长度
   mov eax,esi    //新字符串地址
   Call UniqueString //产生一个唯一的新字符串，串位置在eax中
   Pop ecx
@@SetHex:
   xor edx,edx    //清空edx
   mov dl, [edi]    //Str字符串字符
   mov ebx,edx    //保存当前的字符
   shr edx,4    //右移4字节，得到高8位
   mov dl,byte ptr[edx+@@HexChar] //转换成字符
   mov [eax],dl    //将字符串输入到新建串中存放
   and ebx,$0F    //获得低8位
   mov dl,byte ptr[ebx+@@HexChar] //转换成字符
   inc eax    //移动一个字节,存放低位
   mov [eax],dl
   inc edi
   inc eax
   loop @@SetHex
@@Exit:
   pop edi
   pop esi
   pop ebx
   ret
@@HexChar: db '0123456789ABCDEF'
end;

function HexToStr(const Str: AnsiString): AnsiString;
asm
push ebx
push edi
push esi
test eax,eax //为空串
jz @@Exit
mov edi,eax
mov esi,edx
mov edx,[eax-4]
test edx,edx
je @@Exit
mov ecx,edx
push ecx
shr edx,1
mov eax,esi //开始构造字符串
{$IFDEF VER210}
movzx ecx, word ptr [edi-12] {需要设置CodePage}
{$ENDIF}
call System.@LStrSetLength //设置新串长度
mov eax,esi //新字符串地址
Call UniqueString //产生一个唯一的新字符串，串位置在eax中
Pop ecx
xor ebx,ebx
xor esi,esi
@@CharFromHex:
xor edx,edx
mov dl, [edi] //Str字符串字符
cmp dl, '0' //查看是否在0到f之间的字符
JB @@Exit //小于0，退出
cmp dl,'9' //小于=9
ja @@DoChar//CompOkNum
sub dl,'0'
jmp @@DoConvert
@@DoChar:
//先转成大写字符
and dl,$DF
cmp dl,'F'
ja @@Exit //大于F退出
add dl,10
sub dl,'A'
@@DoConvert: //转化
inc ebx
cmp ebx,2
je @@Num1
xor esi,esi
shl edx,4
mov esi,edx
jmp @@Num2
@@Num1:
add esi,edx
mov edx,esi
mov [eax],dl
xor ebx,ebx
inc eax
@@Num2:
dec ecx
inc edi
test ecx,ecx
jnz @@CharFromHex
@@Exit:
pop esi
pop edi
pop ebx
end;

{ -- 字符串加密函数默认按照 128 位密匙加密 -- }
function EncryptString(Value: AnsiString; Key: AnsiString;
KeyBit: TKeyBit = kb128): AnsiString;
var
{$IFDEF VER210}
SS,DS: TMemoryStream;
{$ELSE}
SS, DS: TStringStream;
{$ENDIF}
Size: Int64;
AESKey128: TAESKey128;
AESKey192: TAESKey192;
AESKey256: TAESKey256;
st: AnsiString;
begin
Result := '';
{$IFDEF VER210}
   ss := TMemoryStream.Create;
   SS.WriteBuffer(PAnsiChar(Value)^,Length(Value));
   DS := TMemoryStream.Create;
{$ELSE}
   SS := TStringStream.Create(Value);
   DS := TStringStream.Create('');
{$ENDIF}
try
   Size := SS.Size;
   DS.WriteBuffer(Size, SizeOf(Size));
   { -- 128 位密匙最大长度为 16 个字符 -- }
   if KeyBit = kb128 then
   begin
   FillChar(AESKey128, SizeOf(AESKey128), 0 );
   Move(PAnsiChar(Key)^, AESKey128, Min(SizeOf(AESKey128), Length(Key)));
   EncryptAESStreamECB(SS, 0, AESKey128, DS);
   end;
   { -- 192 位密匙最大长度为 24 个字符 -- }
   if KeyBit = kb192 then
   begin
   FillChar(AESKey192, SizeOf(AESKey192), 0 );
   Move(PAnsiChar(Key)^, AESKey192, Min(SizeOf(AESKey192), Length(Key)));
   EncryptAESStreamECB(SS, 0, AESKey192, DS);
   end;
   { -- 256 位密匙最大长度为 32 个字符 -- }
   if KeyBit = kb256 then
   begin
   FillChar(AESKey256, SizeOf(AESKey256), 0 );
   Move(PAnsiChar(Key)^, AESKey256, Min(SizeOf(AESKey256), Length(Key)));
   EncryptAESStreamECB(SS, 0, AESKey256, DS);
   end;
   {$IFDEF VER210}
   SetLength(st,Ds.Size);
   DS.Position := 0;
   DS.ReadBuffer(PAnsiChar(st)^,DS.Size);
   Result := StrToHex(st);
   {$ELSE}
   Result := StrToHex(DS.DataString);
   {$ENDIF}
finally
   SS.Free;
   DS.Free;
end;
end;

{ -- 字符串解密函数默认按照 128 位密匙解密 -- }
function DecryptString(Value: AnsiString; Key: AnsiString;
KeyBit: TKeyBit = kb128): AnsiString;
var
SS, DS: TStringStream;
Size: Int64;
AESKey128: TAESKey128;
AESKey192: TAESKey192;
AESKey256: TAESKey256;
begin
Result := '';
SS := TStringStream.Create(HexToStr(Value));
DS := TStringStream.Create('');
try
   Size := SS.Size;
   SS.ReadBuffer(Size, SizeOf(Size));
   { -- 128 位密匙最大长度为 16 个字符 -- }
   if KeyBit = kb128 then
   begin
   FillChar(AESKey128, SizeOf(AESKey128), 0 );
   Move(PAnsiChar(Key)^, AESKey128, Min(SizeOf(AESKey128), Length(Key)));
   DecryptAESStreamECB(SS, SS.Size - SS.Position, AESKey128, DS);
   end;
   { -- 192 位密匙最大长度为 24 个字符 -- }
   if KeyBit = kb192 then
   begin
   FillChar(AESKey192, SizeOf(AESKey192), 0 );
   Move(PAnsiChar(Key)^, AESKey192, Min(SizeOf(AESKey192), Length(Key)));
   DecryptAESStreamECB(SS, SS.Size - SS.Position, AESKey192, DS);
   end;
   { -- 256 位密匙最大长度为 32 个字符 -- }
   if KeyBit = kb256 then
   begin
   FillChar(AESKey256, SizeOf(AESKey256), 0 );
   Move(PAnsiChar(Key)^, AESKey256, Min(SizeOf(AESKey256), Length(Key)));
   DecryptAESStreamECB(SS, SS.Size - SS.Position, AESKey256, DS);
   end;
   Result := DS.DataString;
finally
   SS.Free;
   DS.Free;
end;
end;

{ 流加密函数, default keybit: 128bit }
function EncryptStream(Src: TStream; Key: AnsiString;
var Dest: TStream; KeyBit: TKeyBit = kb128): Boolean;
var
Count: Int64;
AESKey128: TAESKey128;
AESKey192: TAESKey192;
AESKey256: TAESKey256;
begin
if Dest = nil then
begin
   raise Exception.Create(SDestStreamNotCreated);
   Result:= False;
   Exit;
end;

try
   Src.Position:= 0;
   Count:= Src.Size;
   Dest.Write(Count, SizeOf(Count));
   { -- 128 位密匙最大长度为 16 个字符 -- }
   if KeyBit = kb128 then
   begin
   FillChar(AESKey128, SizeOf(AESKey128), 0 );
   Move(PAnsiChar(Key)^, AESKey128, Min(SizeOf(AESKey128), Length(Key)));
   EncryptAESStreamECB(Src, 0, AESKey128, Dest);
   end;
   { -- 192 位密匙最大长度为 24 个字符 -- }
   if KeyBit = kb192 then
   begin
   FillChar(AESKey192, SizeOf(AESKey192), 0 );
   Move(PAnsiChar(Key)^, AESKey192, Min(SizeOf(AESKey192), Length(Key)));
   EncryptAESStreamECB(Src, 0, AESKey192, Dest);
   end;
   { -- 256 位密匙最大长度为 32 个字符 -- }
   if KeyBit = kb256 then
   begin
   FillChar(AESKey256, SizeOf(AESKey256), 0 );
   Move(PAnsiChar(Key)^, AESKey256, Min(SizeOf(AESKey256), Length(Key)));
   EncryptAESStreamECB(Src, 0, AESKey256, Dest);
   end;

   Result := True;
except
   raise Exception.Create(SEncryptStreamError);
   Result:= False;
end;
end;

{ 流解密函数, default keybit: 128bit }
function DecryptStream(Src: TStream; Key: AnsiString;
var Dest: TStream; KeyBit: TKeyBit = kb128): Boolean;
var
Count, OutPos: Int64;
AESKey128: TAESKey128;
AESKey192: TAESKey192;
AESKey256: TAESKey256;
begin
if Dest = nil then
begin
   raise Exception.Create(SDestStreamNotCreated);
   Result:= False;
   Exit;
end;

try
   Src.Position:= 0;
   OutPos:= Dest.Position;
   Src.ReadBuffer(Count, SizeOf(Count));
   { -- 128 位密匙最大长度为 16 个字符 -- }
   if KeyBit = kb128 then
   begin
   FillChar(AESKey128, SizeOf(AESKey128), 0 );
   Move(PAnsiChar(Key)^, AESKey128, Min(SizeOf(AESKey128), Length(Key)));
   DecryptAESStreamECB(Src, Src.Size - Src.Position,
   AESKey128, Dest);
   end;
   { -- 192 位密匙最大长度为 24 个字符 -- }
   if KeyBit = kb192 then
   begin
   FillChar(AESKey192, SizeOf(AESKey192), 0 );
   Move(PAnsiChar(Key)^, AESKey192, Min(SizeOf(AESKey192), Length(Key)));
   DecryptAESStreamECB(Src, Src.Size - Src.Position,
   AESKey192, Dest);
   end;
   { -- 256 位密匙最大长度为 32 个字符 -- }
   if KeyBit = kb256 then
   begin
   FillChar(AESKey256, SizeOf(AESKey256), 0 );
   Move(PAnsiChar(Key)^, AESKey256, Min(SizeOf(AESKey256), Length(Key)));
   DecryptAESStreamECB(Src, Src.Size - Src.Position,
   AESKey256, Dest);
   end;
   Dest.Size := OutPos + Count;
   Dest.Position := OutPos;

   Result := True;
except
   raise Exception.Create(SDecryptStreamError);
   Result:= False;
end;
end;

{ -- 文件加密函数默认按照 128 位密匙解密 -- }
procedure EncryptFile(SourceFile, DestFile: String;
Key: AnsiString; KeyBit: TKeyBit = kb128);
var
SFS, DFS: TFileStream;
Size: Int64;
AESKey128: TAESKey128;
AESKey192: TAESKey192;
AESKey256: TAESKey256;
begin
SFS := TFileStream.Create(SourceFile, fmOpenRead);
try
   DFS := TFileStream.Create(DestFile, fmCreate);
   try
   Size := SFS.Size;
   DFS.WriteBuffer(Size, SizeOf(Size));
   { -- 128 位密匙最大长度为 16 个字符 -- }
   if KeyBit = kb128 then
   begin
   FillChar(AESKey128, SizeOf(AESKey128), 0 );
   Move(PAnsiChar(Key)^, AESKey128, Min(SizeOf(AESKey128), Length(Key)));
   EncryptAESStreamECB(SFS, 0, AESKey128, DFS);
   end;
   { -- 192 位密匙最大长度为 24 个字符 -- }
   if KeyBit = kb192 then
   begin
   FillChar(AESKey192, SizeOf(AESKey192), 0 );
   Move(PAnsiChar(Key)^, AESKey192, Min(SizeOf(AESKey192), Length(Key)));
   EncryptAESStreamECB(SFS, 0, AESKey192, DFS);
   end;
   { -- 256 位密匙最大长度为 32 个字符 -- }
   if KeyBit = kb256 then
   begin
   FillChar(AESKey256, SizeOf(AESKey256), 0 );
   Move(PAnsiChar(Key)^, AESKey256, Min(SizeOf(AESKey256), Length(Key)));
   EncryptAESStreamECB(SFS, 0, AESKey256, DFS);
   end;
   finally
   DFS.Free;
   end;
finally
   SFS.Free;
end;
end;

{ -- 文件解密函数默认按照 128 位密匙解密 -- }
procedure DecryptFile(SourceFile, DestFile: String;
Key: AnsiString; KeyBit: TKeyBit = kb128);
var
SFS, DFS: TFileStream;
Size: Int64;
AESKey128: TAESKey128;
AESKey192: TAESKey192;
AESKey256: TAESKey256;
begin
SFS := TFileStream.Create(SourceFile, fmOpenRead);
try
   SFS.ReadBuffer(Size, SizeOf(Size));
   DFS := TFileStream.Create(DestFile, fmCreate);
   try
   { -- 128 位密匙最大长度为 16 个字符 -- }
   if KeyBit = kb128 then
   begin
   FillChar(AESKey128, SizeOf(AESKey128), 0 );
   Move(PAnsiChar(Key)^, AESKey128, Min(SizeOf(AESKey128), Length(Key)));
   DecryptAESStreamECB(SFS, SFS.Size - SFS.Position, AESKey128, DFS);
   end;
   { -- 192 位密匙最大长度为 24 个字符 -- }
   if KeyBit = kb192 then
   begin
   FillChar(AESKey192, SizeOf(AESKey192), 0 );
   Move(PAnsiChar(Key)^, AESKey192, Min(SizeOf(AESKey192), Length(Key)));
   DecryptAESStreamECB(SFS, SFS.Size - SFS.Position, AESKey192, DFS);
   end;
   { -- 256 位密匙最大长度为 32 个字符 -- }
   if KeyBit = kb256 then
   begin
   FillChar(AESKey256, SizeOf(AESKey256), 0 );
   Move(PAnsiChar(Key)^, AESKey256, Min(SizeOf(AESKey256), Length(Key)));
   DecryptAESStreamECB(SFS, SFS.Size - SFS.Position, AESKey256, DFS);
   end;
   DFS.Size := Size;
   finally
   DFS.Free;
   end;
finally
   SFS.Free;
end;
end;
end.

加密解密

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