Курсовая работа: Програмна реалізація криптографічного алгоритму RC5

end;

end;

////////////////////////////////////////////////////////////////////////////////

function EncryptStream(DataStream: TStream; Count: Int64; Key: string): Boolean;

var

Buffer : TRC5Block;

PrCount : Int64;

begin

Result := True;

try

if Key = '' then

begin

DataStream.Seek(Count, soFromCurrent);

Exit;

end;

Initialize(Key);

CalculateSubKeys;

PrCount := 0;

while Count - PrCount >= 8 do

begin

DataStream.Read(Buffer, BlockSize);

EncipherBlock(Buffer);

DataStream.Seek(-BlockSize, soFromCurrent);

DataStream.Write(Buffer, BlockSize);

Inc(PrCount, 8);

end;

except

Result := False;

end;