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Below code shows the way to save the necessary secret information in Delphi. For your information, if you want to increase the size of the message, you should increase the value of CK_MAX_MSG_LEN below.
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const CK_SINGATURE = '!CK!';
const CK_MAX_MSG_LEN = 1024*8;
function CKReadPassword(sFileName:string):string;
var
sFile: TFileStream;
lenPWD, lenPWD_old: WORD;
sEncryptedPWD: AnsiString;
buff: PAnsiChar;
begin
GetMem( buff, CK_MAX_MSG_LEN);
ZeroMemory( buff, CK_MAX_MSG_LEN);
if FileExists(sFileName) then begin
lenPWD_old := 0;
sFile := TFileStream.Create( sFileName, fmOpenRead);
if sFile.Handle<>THandle(nil) then begin
sFile.Seek( -4, soFromEnd);
sFile.Read( PAnsiChar(buff)^, 4);
if buff=CK_SINGATURE then
begin
// has master key, so need to erase it
sFile.Seek( -6, soFromEnd);
sFile.Read( lenPwd, 2);
sFile.Seek( -(lenPWD + 6), soFromEnd);
sFile.Read( PAnsIChar(buff)^, lenPWD);
Result := trim(string(buff));
end;
sFile.Destroy;
end;
end;
FreeMem(buff);
end;
function CKUpdatePassword(sFileName, sPWD:String):Boolean;
var
sFile: TFileStream;
lenPWD, lenPWD_old: WORD;
sEncryptedPWD: AnsiString;
buff: PAnsiChar;
begin
GetMem( buff, CK_MAX_MSG_LEN);
ZeroMemory( buff, CK_MAX_MSG_LEN);
if not FileExists(sFileName) then begin
Result := False;
end else begin
lenPWD_old := 0;
sFile := TFileStream.Create( sFileName, fmOpenReadWrite);
if sFile.Handle<>THandle(nil) then begin
sFile.Seek( -4, soFromEnd);
sFile.Read( PAnsiChar(buff)^, 4);
if buff=CK_SINGATURE then
begin
// has master key, so need to erase it
sFile.Seek( -6, soFromEnd);
sFile.Read( lenPwd, 2);
sFile.Seek( -(lenPWD + 6), soFromEnd);
lenPWD_old := lenPWD;
end else sFile.Seek( 0, soFromEnd);
while Length(sPWD)<lenPWD_old do sPWD := sPWD + ' ';
sEncryptedPWD := AnsiString(sPWD);
lenPWD := Length(sEncryptedPWD);
sFile.Write( PAnsiChar(sEncryptedPWD)^, lenPWD);
sFile.Write( lenPWD, 2);
sFile.Write( PAnsiChar(CK_SINGATURE)^, 4);
sFile.Destroy;
Result := True;
end else Result := False;
end;
FreeMem(buff);
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
if not FileExists(eMasterFile.Text) then begin
ShowMessage( 'Please select program file you want');
end else begin
if (CKUpdatePassword( eMasterFile.Text, ePWD.Text)=True) then begin
ShowMessage('Successfully Changed !!');
Close;
end;
end;
end;
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uses IdCoder, IdCoderMIME, IdGlobal;
.
.
.
const CK_SINGATURE = '!CK!';
const CK_SINGATURE_KEY = 'ChunKang';
const CK_MAX_MSG_LEN = 1024 * 8;
const CK_ENC_VAR_RANGE=10;
function CKEncrypt(const Source:string; Salt:string): string;
var
i, lenSalt, key, keyWeight: Word;
InString: string;
begin
Result := '';
if (Salt = '') then begin
Result := Source;
end else begin
InString := TIdEncoderMIME.EncodeString(Source, IndyTextEncoding_UTF8);
lenSalt := Length(Salt);
keyWeight := 0;
for i := 1 to lenSalt do keyWeight := keyWeight + ord(Salt[i]);
keyWeight := keyWeight mod CK_ENC_VAR_RANGE;
for i := 1 to Length(InString) do
begin
key := ( ord(Salt[(i mod lenSalt) + 1]) mod CK_ENC_VAR_RANGE);
Result := Result + CHAR(Byte(InString[i]) + key - keyWeight);
end;
end;
end;
function CKDecrypt(const InString:string; Salt:string): string;
var
i, lenSalt, key, keyWeight: Word;
Target: string;
begin
if (Salt = '') then begin
Target := InString;
end else begin
lenSalt := Length(Salt);
keyWeight := 0;
for i := 1 to lenSalt do keyWeight := keyWeight + ord(Salt[i]);
keyWeight := keyWeight mod CK_ENC_VAR_RANGE;
Target := '';
for i := 1 to Length(InString) do
begin
key := ( ord(Salt[(i mod lenSalt) + 1]) mod CK_ENC_VAR_RANGE);
Target := Target + CHAR(Byte(InString[i]) - key + keyWeight);
end;
Result := TIdDecoderMIME.DecodeString(Target, IndyTextEncoding_UTF8);
end;
end;
function CKReadPassword(sFileName:string):string;
var
sFile: TFileStream;
lenPWD, lenPWD_old: WORD;
sEncryptedPWD: AnsiString;
buff: PAnsiChar;
tmp: AnsiString;
begin
GetMem( buff, CK_MAX_MSG_LEN);
ZeroMemory( buff, CK_MAX_MSG_LEN);
if FileExists(sFileName) then begin
lenPWD_old := 0;
sFile := TFileStream.Create( sFileName, fmOpenRead);
if sFile.Handle<>THandle(nil) then begin
sFile.Seek( -4, soFromEnd);
sFile.Read( PAnsiChar(buff)^, 4);
if buff=CK_SINGATURE then
begin
// has master key, so need to erase it
sFile.Seek( -6, soFromEnd);
sFile.Read( lenPwd, 2);
sFile.Seek( -(lenPWD + 6), soFromEnd);
sFile.Read( PAnsIChar(buff)^, lenPWD);
tmp := ansiString(string(buff));
tmp := CKDecrypt( tmp, CK_SINGATURE_KEY);
Result := Trim(tmp);
end;
sFile.Destroy;
end;
end;
FreeMem(buff);
end;
function CKUpdatePassword(sFileName, sPWD:String):Boolean;
var
sFile: TFileStream;
lenPWD, lenPWD_old: WORD;
sEncryptedPWD: AnsiString;
buff: PAnsiChar;
begin
GetMem( buff, CK_MAX_MSG_LEN);
ZeroMemory( buff, CK_MAX_MSG_LEN);
if not FileExists(sFileName) then begin
Result := False;
end else begin
lenPWD_old := 0;
sFile := TFileStream.Create( sFileName, fmOpenReadWrite);
if sFile.Handle<>THandle(nil) then begin
sFile.Seek( -4, soFromEnd);
sFile.Read( PAnsiChar(buff)^, 4);
if buff=CK_SINGATURE then
begin
// has master key, so need to erase it
sFile.Seek( -6, soFromEnd);
sFile.Read( lenPwd, 2);
sFile.Seek( -(lenPWD + 6), soFromEnd);
lenPWD_old := lenPWD;
end else sFile.Seek( 0, soFromEnd);
while Length(sPWD)<lenPWD_old do sPWD := sPWD + ' ';
sEncryptedPWD := CKEncrypt(sPWD, CK_SINGATURE_KEY);
lenPWD := Length(sEncryptedPWD);
sFile.Write( PAnsiChar(sEncryptedPWD)^, lenPWD);
sFile.Write( lenPWD, 2);
sFile.Write( PAnsiChar(CK_SINGATURE)^, 4);
sFile.Destroy;
Result := True;
end else Result := False;
end;
FreeMem(buff);
end; |
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