Delphi AES加密(转)

(**************************************************************)
(*     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,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 [email?protected] //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[[email?protected]@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[[email?protected]@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 [email?protected] //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,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,DS);
    end;
    {  --  192 位密匙最大长度为 24 个字符 --  }
    if KeyBit = kb192 then
    begin
      FillChar(AESKey192,SizeOf(AESKey192),AESKey192,Min(SizeOf(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),AESKey256,Min(SizeOf(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,Length(Key)));
      DecryptAESStreamECB(SS,SS.Size - SS.Position,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,Length(Key)));
      EncryptAESStreamECB(Src,Dest);
    end;
    {  --  192 位密匙最大长度为 24 个字符 --  }
    if KeyBit = kb192 then
    begin
      FillChar(AESKey192,Dest);
    end;
    {  --  256 位密匙最大长度为 32 个字符 --  }
    if KeyBit = kb256 then
    begin
      FillChar(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,Length(Key)));
      DecryptAESStreamECB(Src,Src.Size - Src.Position,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(AESKey128,0 );
        Move(PAnsiChar(Key)^,Length(Key)));
        EncryptAESStreamECB(SFS,DFS);
      end;
      {  --  192 位密匙最大长度为 24 个字符 --  }
      if KeyBit = kb192 then
      begin
        FillChar(AESKey192,DFS);
      end;
      {  --  256 位密匙最大长度为 32 个字符 --  }
      if KeyBit = kb256 then
      begin
        FillChar(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,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,Length(Key)));
        DecryptAESStreamECB(SFS,SFS.Size - SFS.Position,DFS);
      end;
      DFS.Size := Size;
    finally
      DFS.Free;
    end;
  finally
    SFS.Free;
  end;
end;
end.