[DEC] WideString ver/entschlüsseln

[negaH]

als nächstes wandeln wir diese Funktionen in WideString Funktionen um

Delphi-Quellcode:

var
  ACipherClass: TDECCipherClass = TCipher_Rijndael;
  ACipherMode: TCipherMode = cmCBCx;
  AHashClass: TDECHashClass = THash_SHA1;
  ATextFormat: TDECFormatClass = TFormat_MIME64;
  AKDFIndex: LongWord = 1;
                            
function Encrypt(const AText: WideString; const APassword: WideString): String;
var   
  ASalt: Binary;
  AData: Binary;
  APass: Binary;
begin
  with ValidCipher(ACipherClass).Create, Context do
  try
    ASalt := RandomBinary(16);
    APass := ValidHash(AHashClass).KDFx(APassword[1], Length(APassword) * 2, ASalt[1], Length(ASalt), KeySize, TFormat_Copy, AKDFIndex);
    Mode := ACipherMode;
    Init(APass);
    SetLength(AData, Length(AText) * 2);
    Encode(AText[1], AData[1], Length(AData));
    Result := ValidFormat(ATextFormat).Encode(ASalt + AData + CalcMAC);
  finally
    Free;
    ProtectBinary(ASalt);
    ProtectBinary(AData);
    ProtectBinary(APass);
  end;
end;

function Decrypt(const AText: String; const APassword: WideString): WideString;
var
  ASalt: Binary;
  AData: Binary;
  ACheck: Binary;
  APass: Binary;
  ALen: Integer;
begin
  with ValidCipher(ACipherClass).Create, Context do
  try
    ASalt := ValidFormat(ATextFormat).Decode(AText);
    ALen := Length(ASalt) -16 -BufferSize;
    AData := System.Copy(ASalt, 17, ALen);
    ACheck := System.Copy(ASalt, ALen +17, BufferSize);
    SetLength(ASalt, 16);
    APass := ValidHash(AHashClass).KDFx(APassword[1], Length(APassword) *2, ASalt[1], Length(ASalt), KeySize, TFormat_Copy, AKDFIndex);
    Mode := ACipherMode;
    Init(APass);
    Result := DecodeBinary(AData);
    if ACheck <> CalcMAC then
      raise Exception.Create('Invalid data');
  finally
    Free;
    ProtectBinary(ASalt);
    ProtectBinary(AData);
    ProtectBinary(ACheck);
    ProtectBinary(APass);
  end;
end;

Beachte dabei das das Datenformat der verschlüsselten Daten als normaler LongString verarbeitet wird, bei MIME64 Format ist dies kein Problem da dieses auf Grund des Zeichensatzes für beide Datentypen, LongString und WideString, kompatibel ist.

Gruß Hagen