AES crypt Delphi/PHP corrupted output

Question

I encrypt some data in Delphi and send it via GET to PHP script which decrypts it and adds result to MySQL database. The problem is it sometimes adds one "�" or more "���" at the end of data. Here is the code:

const
  URL = 'http://127.0.0.1/script.php?data=';
  PACK_SEPARATOR = '|';
  KeySize = 32;
  BlockSize = 16;

function aes_encrypt(const Data: string; const Key: string; const IV: string) : string;
var
  Cipher : TDCP_rijndael;
  tempData, tempKey, tempIV : string;
begin
  tempKey := PadWithZeros(Key,KeySize);
  tempIV := PadWithZeros(IV,BlockSize);
  tempData := PadWithZeros(Data,BlockSize);
  Cipher := TDCP_rijndael.Create(nil);
  if Length(Key) <= 16 then
    Cipher.Init(tempKey[1],128,@tempIV[1])
  else if Length(Key) <= 24 then
    Cipher.Init(tempKey[1],192,@tempIV[1])
  else
    Cipher.Init(tempKey[1],256,@tempIV[1]);
  Cipher.EncryptCBC(tempData[1],tempData[1],Length(tempData));
  Cipher.Free;
  FillChar(tempKey[1],Length(tempKey),0);
  Result := Base64EncodeStr(tempData);
end;


function PadWithZeros(const str : string; size : integer) : string;
var
  origsize, i : integer;
begin
  Result := str;
  origsize := Length(Result);
  if ((origsize mod size) <> 0) or (origsize = 0) then
  begin
    SetLength(Result,((origsize div size)+1)*size);
    for i := origsize+1 to Length(Result) do
      Result[i] := #0;
  end;
end;

function HTTPEncode(const AStr: String): String;
const
  NoConversion = ['A'..'Z','a'..'z','*','@','.','_','-'];
var
  Sp, Rp: PChar;
begin
  SetLength(Result, Length(AStr) * 3);
  Sp := PChar(AStr);
  Rp := PChar(Result);
  while Sp^ <> #0 do
  begin
    if Sp^ in NoConversion then
      Rp^ := Sp^
    else
      if Sp^ = ' ' then
        Rp^ := '+'
      else
      begin
        FormatBuf(Rp^, 3, '%%%.2x', 6, [Ord(Sp^)]);
        Inc(Rp,2);
      end;
    Inc(Rp);
    Inc(Sp);
  end;
  SetLength(Result, Rp - PChar(Result));
end;


packedData := Memo1.Lines.Text + PACK_SEPARATOR + Edit1.Text + PACK_SEPARATOR + Edit2.Text;
encryptedData := aes_encrypt(packedData, KEY, IV);
encryptedData := HTTPEncode(encryptedData);
serverMsg := DownloadFile(URL+encryptedData);

'packedData' length before encryption is about 133. After encryption about 200 so it isn't break some servers GET data limit.

Now PHP code:

function aes_decrypt($dataToDecrypt, $key, $iv)
{
    $decoded = base64_decode($dataToDecrypt);
    $decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $decoded, MCRYPT_MODE_CBC, $iv);
    return $decrypted;
}

$packedData = aes_decrypt($_GET['data'], KEY, IV);
$unpacked = explode(PACK_SEPARATOR, $packedData);
$smth1 = $unpacked[0];
$smth2 = $unpacked[1];
$smth3 = $unpacked[2];
$params = array(':thing' => $somevar, ':data1' => $smth1, ':data2' => $smth2, ':data3' => $smth3);
$query = $pdo->prepare('UPDATE one_table SET somedata1 = :data1 , somedata2 = :data2 , somedata3 = :data3 WHERE something = :thing LIMIT 1'); 
$success = $query->execute($params);

I spend really many hours trying to resolve this problem. Some time ago I had problems with encrypted PHP output with binary data, the problem was aes_decrypt function so I changed it into you can see above. Right now I don't know where is the problem. Delphi encrypt, PHP decrypt or in sending data via GET? Thank you for any help you are able to provide.

Answer 1

Looks like a encoding problem with diffrent character sets. Check the character sets you use in delphi and php. I can imagine that your strings are latin-1 in delphi and UTF-8 in php. And because of that some strange symbols appears.

Answer 2

This is my Delphi XE3 and PHP code :

Delphi XE3 code :

uses IdHash, IdCoderMIME, IdHashMessageDigest,
     DCPrijndael, DCPbase64;

function xBase64Encode(const Input: string): AnsiString;
    begin
      result := TIdEncoderMIME.EncodeString(Input, TEncoding.UTF8);
    end;

    function xBase64Decode(const Input: AnsiString): string;
    begin
      result := TIdDecoderMIME.DecodeString(Input, TEncoding.UTF8);
    end;

    function PadWithZeros(const str: AnsiString; size: integer): AnsiString;
    var
      origsize, i: integer;
    begin
      Result := str;
      origsize := Length(Result);
      if ((origsize mod size) <> 0) or (origsize = 0) then
      begin
        SetLength(Result, ((origsize div size) + 1) * size);
        for i := origsize + 1 to Length(Result) do
          Result[i] := #0;
      end;
    end;

    function AES_Rijndael_Encript(xData, xKey, xIV: string): string;
        var
          Cipher: TDCP_rijndael;
          B64, Data, Key, IV: AnsiString;
        begin
          B64 := xBase64Encode(xData);
          // Pad Key, IV and Data with zeros as appropriate
          Key := PadWithZeros(AnsiString(xKey), KeySize);
          IV := PadWithZeros(AnsiString(xIV), BlockSize);
          Data := PadWithZeros(B64, BlockSize);
          // Create the cipher and initialise according to the key length
          Cipher := TDCP_rijndael.Create(nil);
          if Length(AnsiString(xKey)) <= 16 then
            Cipher.Init(Key[1], 128, @IV[1])
          else if Length(AnsiString(xKey)) <= 24 then
            Cipher.Init(Key[1], 192, @IV[1])
          else
            Cipher.Init(Key[1], 256, @IV[1]);
          // Encrypt the data
          Cipher.EncryptCBC(Data[1], Data[1], Length(Data));
          // Free the cipher and clear sensitive information
          Cipher.Free;
          FillChar(Key[1], Length(Key), 0);
          // Display the Base64 encoded result
          Result := Base64EncodeStr(Data);
        end;

        function AES_Rijndael_Decript(xData, xKey, xIV: string): string;
        var
          Cipher : TDCP_rijndael;
          Data, Key, IV : ansistring;
          xResult : string;
        begin
          // Pad Key and IV with zeros as appropriate
          Key := PadWithZeros(ansistring(xKey),KeySize);
          IV := PadWithZeros(ansistring(xIV),BlockSize);
          // Decode the Base64 encoded string
          Data := Base64DecodeStr(ansistring(xData));
          // Create the cipher and initialise according to the key length
          Cipher := TDCP_rijndael.Create(nil);
          if Length(ansistring(xKey)) <= 16 then
            Cipher.Init(Key[1],128,@IV[1])
          else if Length(ansistring(xKey)) <= 24 then
            Cipher.Init(Key[1],192,@IV[1])
          else
            Cipher.Init(Key[1],256,@IV[1]);
          // Decrypt the data
          Cipher.DecryptCBC(Data[1],Data[1],Length(Data));
          // Free the cipher and clear sensitive information
          Cipher.Free;
          FillChar(Key[1],Length(Key),0);
          // Display the result
          Result :=  Data;
          xResult :=  Trim(Data);
          Result := xBase64Decode(xResult);
        end;

How to user function :

boxKey.Text := 'gmAetc4EydWJg2TcnH34';
boxIV.Text := 'AHsq3SCN7usJzqLi';

Memo2.Lines.Text := AES_Rijndael_Encript(Memo1.Lines.Text, boxKey.Text, boxIV.Text);
Memo1.Lines.Text := AES_Rijndael_Decript(Memo2.Lines.Text, boxKey.Text, boxIV.Text);

PHP code :

public function AES_Rijndael_Decript($data) {
        $key = 'gmAetc4EydWJg2TcnH34';
        $iv = 'AHsq3SCN7usJzqLi';
        return base64_decode(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($data), MCRYPT_MODE_CBC, $iv));
    }
    public function AES_Rijndael_Encript($data) {
        $key = 'gmAetc4EydWJg2TcnH34';
        $iv = 'AHsq3SCN7usJzqLi';
        return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_128,$key,base64_encode($data),MCRYPT_MODE_CBC,$iv));        
    }