function StreamToHexStr(AStream: TStream): String;
const
HexChars: array[0..15] of Char = '0123456789ABCDEF';
var
i,len: Integer;
begin
len := AStream.Size - AStream.Position;
SetLength(Result, len * 2);
AStream.Read(Pointer(Result)^, len);
for i := len downto 1 do begin
Result[i * 2] := HexChars[Byte(Result[i]) and $0F];
Result[i * 2 -1] := HexChars[(Byte(Result[i]) and $F0) shr 4]
end;
end;