For years, I have been using a bit of code in Xojo to call a php script that decode it.
Unfortunately, my provide chnged php version, and now old mdecrypt_generic does not wotk anymore…
Here is the Xojo code
'dim a as new AESMBS // 1.7f4
Dim a As AESMBS
Dim key256 As String = TheKey256 // 32 characters
dim iv as MemoryBlock = iv // 16 characters
Dim TheKey256 As MemoryBlock = TheKey256
Call a.SetKey TheKey256, 256// 1.7f4 OK
// PHP pads with NULL bytes if $cleartext is not a multiple of the block size..
while lenb(ClearText) mod 16 <> 0
ClearText = ClearText + chrb(0)
Dim idata As MemoryBlock = cleartext
dim odata as new MemoryBlock(idata.Size)
dim cipherText as string
a.EncryptCBC idata, idata.Size, iv, odata, 0, 0
cipherText = odata
return EncodingToHexMBS ( cipherText )
// Your function:
Var my_iv As MemoryBlock = iv
Var mykey As String = TheKey256
Var data_unencrypted As MemoryBlock = cleartext
Var data_encrypted As String = Cryto.AESEncrypt(mykey, data_unencrypted, Crypto.BlockModes.CBC, my_iv)
Var hex_data As String = EncodeHex(data_encrypted)
I believe the padding is automated in xojo, but i’m not sure. Just try the code.
I have tried DerJ’s code without any success.
I have tried different combinaisons :
Algo : aes-128-cbc and aes-128-cbc,
With or without InitVector,
I’m quite sure I have to use the OPENSSL_ZERO_PADDING option, as I add chrb(0) in my Xojo code above.
Concerning the algo to use, I saw here :
that a « aes-256-cbc » should be the way.
Quote at the end of the page :
I believe Mcrypt provides block sizes of 128, 192 and 256 bits. AES only provides the 128 block size. My guess is, MCRYPT_RIJNDAEL_128 is probably referring to Rijndael with 128-bit block size, which is AES. The key size is a different matter, and that is what the 256 denotes in OpenSSL’s AES-256-CBC. If using a Standard Cryptographic Algorithm Name (SCAN), then the Mcrypt algorithm name for the cipher instance would be similar to Rijndael-128(256)/CBC.
Anyway, nothing seems to work.
So, I ‘m still stuck with my php script…
Keeping on searching, I found that
PHP’s AES encryption.
// The first thing to understand is the meaning of these constants:
// You would think that MCRYPT_RIJNDAEL_256 specifies 256-bit encryption,
// but that is wrong. The three choices specify the block-size to be used
// with Rijndael encryption. They say nothing about the key size (i.e. strength)
// of the encryption. (Read further to understand how the strength of the
// AES encryption is set.)
// The Rijndael encyrption algorithm is a block cipher. It operates on discrete
// blocks of data. Padding MUST be added such that
// the data to be encrypted has a length that is a multiple of the block size.
// (PHP pads with NULL bytes)
// Thus, if you specify MCRYPT_RIJNDAEL_256, your encrypted output will always
// be a multiple of 32 bytes (i.e. 256 bits). If you specify MCRYPT_RIJNDAEL_128,
// your encrypted output will always be a multiple of 16 bytes.
// Note: Strictly speaking, AES is not precisely Rijndael (although in practice
// they are used interchangeably) as Rijndael supports a larger range of block
// and key sizes; AES has a fixed block size of 128 bits and a key size of
// 128, 192, or 256 bits, whereas Rijndael can be specified with key and block
// sizes in any multiple of 32 bits, with a minimum of 128 bits and a maximum of
// 256 bits.
// In summary: If you want to be AES compliant, always choose MCRYPT_RIJNDAEL_128.
// So the first step is to create the cipher object:
$cipher = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
// We're using CBC mode (cipher-block chaining). Block cipher modes are detailed
// here: http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation
It does not explain how to decode using OpenSSL, but explain what is done when crypting.