different Delphi / PHP Encryption-Decryption using Rijndael

Question

I am trying to encrypt / decrypt a string using Rijndael from php to Delphi and back.

If I decrypt a PHP string from Delphi ... works fine.

If I encrypt a string with Delphi the result string is ok but shorter

for test I used a string with 62 character. the encrypted string with delphi is long 4 char less of PHP

these the strings ... last characters:

PHP: GyLWj1anBJRmE8mBsaO5cvTrcbvvA==

Delphi: GyLWj1anBJRmE8mBsaO5cvTrcbv

thanks for any advices

I use this source code example:

PHP:

function encrypt ($key, $value)
{
  $padSize = 16 - (strlen ($value) % 16) ;
  $value = $value . str_repeat (chr ($padSize), $padSize) ;
  $output = mcrypt_encrypt (MCRYPT_RIJNDAEL_128, $key, $value, MCRYPT_MODE_CBC, 'xxxxxxx') ;
  return base64_encode ($output) ;
}

Delphi encrypt:

function EncryptData3(Data: string; AKey: AnsiString; AIv: AnsiString): string;
var
  cipher: TDCP_rijndael;
  key, iv, src, dest, b64: TBytes;
  index, slen, bsize, pad: integer;
begin
  //key := Base64DecodeBytes(TEncoding.UTF8.GetBytes(AKey));
  //iv := Base64DecodeBytes(TEncoding.UTF8.GetBytes(AIv));
  key := TEncoding.ASCII.GetBytes(AKey);
  iv := TEncoding.ASCII.GetBytes(AIv);

  src := TEncoding.ascii.GetBytes(Data);

  cipher := TDCP_rijndael.Create(nil);
  try
    cipher.CipherMode := cmCBC;
    // Add padding.
    // Resize the Value array to make it a multiple of the block length.
    // If it's already an exact multiple then add a full block of padding.
    slen := Length(src);
    bsize := (cipher.BlockSize div 8);
    pad := bsize - (slen mod bsize);
    Inc(slen, pad);
    SetLength(src, slen);

    for index := pad downto 1 do
    begin
      src[slen - index] := pad;
    end;

    SetLength(dest, slen);
    cipher.Init(key[0], 256, @iv[0]); // DCP uses key size in BITS not BYTES
    cipher.Encrypt(src[0], dest[0], slen);

    b64 := Base64EncodeBytes(dest);
    result := TEncoding.Default.GetString(b64);
  finally
    cipher.Free;
  end;
end;

Delphi decrypt ... not works:

function DecryptData3(Data: string; AKey: AnsiString; AIv: AnsiString): string;
var
  key, iv, src, dest: TBytes;
  cipher: TDCP_rijndael;
  slen, pad: integer;
begin
  //key := Base64DecodeBytes(TEncoding.UTF8.GetBytes(AKey));
  //iv := Base64DecodeBytes(TEncoding.UTF8.GetBytes(AIv));
  key := TEncoding.ASCII.GetBytes(AKey);
  iv := TEncoding.ASCII.GetBytes(AIv);

  src := Base64DecodeBytes(TEncoding.UTF8.GetBytes(Data));

  cipher := TDCP_rijndael.Create(nil);
  try
    cipher.CipherMode := cmCBC;
    slen := Length(src);
    SetLength(dest, slen);
    cipher.Init(key[0], 256, @iv[0]); // DCP uses key size in BITS not BYTES
    cipher.Decrypt(src[0], dest[0], slen);
    // Remove the padding. Get the numerical value of the last byte and remove
    // that number of bytes
    pad := dest[slen - 1];
    SetLength(dest, slen - pad);

    // Base64 encode it
    result := TEncoding.Default.GetString(dest);
  finally
    cipher.Free;
  end;
end;

Answer 1

I don't know if I used a correct way ... but if I convert the Bytes Value in String and I use this Base64Encode in this link:

Simple code to encrypt an .INI file string using a password

now I encrypt correctly. this is the example:

SetString(stringValue, PAnsiChar(@dest[0]), slen); 
result := Base64Encode2(stringValue);