Encryption String From PHP, Decryption String From ASP Big Problem, Urgent !!!

[Kelvin]

Hi All,

I have still problem on Encryption string using, decryption string
using ASP/VB/C#.. I don't know why have different results and using
same algorithm.
Please advise.

PHP Sources Code
<?php
$key = "pg";
$random_number = kelvintai;
$encrypted=encrypt($key,$random_number);
$decrypted=decrypt($key,$encrypted);

echo "NUMBER: $random_number<br>
ENCRYPTED VALUE: $encrypted<br>
DECRYPTED VALUE: $decrypted";

/* Your functions without the comments are below */

function encrypt($key, $plain_text) {
$plain_text = trim($plain_text);
$iv = substr(md5($key), 0,mcrypt_get_iv_size
(MCRYPT_CAST_128,MCRYPT_MODE_ECB));
$c_t = mcrypt_ecb (MCRYPT_CAST_128, $key, $plain_text, MCRYPT_ENCRYPT,
$iv);
return trim(chop(base64_encode($c_t)));
}

function decrypt($key, $c_t) {
$c_t = trim(chop(base64_decode($c_t)));
$iv = substr(md5($key), 0,mcrypt_get_iv_size
(MCRYPT_CAST_128,MCRYPT_MODE_ECB));
$p_t = mcrypt_ecb (MCRYPT_CAST_128, $key, $c_t, MCRYPT_DECRYPT, $iv);
return trim(chop($p_t));
}
?>

ASP.NET/VB.NET Sources Code.

Public Shared Function DecryptTripleDES(ByVal sOut As String, ByVal
sKey As String) As String

Dim DES As New
System.Security.Cryptography.TripleDESCryptoServiceProvider

Dim hashMD5 As New
System.Security.Cryptography.MD5CryptoServiceProvider

' scramble the key
sKey = ScrambleKey(sKey)

' Compute the MD5 hash.
DES.Key = hashMD5.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(sKey))

' Set the cipher mode.
DES.Mode = System.Security.Cryptography.CipherMode.ECB

' Create the decryptor.
Dim DESDecrypt As
System.Security.Cryptography.ICryptoTransform = DES.CreateDecryptor()

Dim Buffer As Byte() = Convert.FromBase64String(sOut)

' Transform and return the string.
Return System.Text.ASCIIEncoding.ASCII.GetString(DESDecrypt.TransformFinalBlock(Buffer,
0, Buffer.Length))

End Function

Private Shared Function ScrambleKey(ByVal v_strKey As String) As
String

Dim sbKey As New System.Text.StringBuilder
Dim intPtr As Integer
For intPtr = 1 To v_strKey.Length
Dim intIn As Integer = v_strKey.Length - intPtr + 1
sbKey.Append(Mid(v_strKey, intIn, 1))
Next

Dim strKey As String = sbKey.ToString

Return sbKey.ToString

End Function

 

[Nick Malik [Microsoft]]

There could be a dozen different reasons... encoding differences, use of
keys, differences in the way null characters are handled, etc. Not being an
expert in PHP and not a full time user of crypto-API, I'm not having much
luck spotting it.

I would like to know why the ASP code feels the need to "scramble the key"
(a misnomer since it appends as series of digits to it: the same digits are
added to every key). The PHP code makes no attempt to do this, as far as I
can tell.

--
--- Nick Malik [Microsoft]
MCSD, CFPS, Certified Scrummaster
http://blogs.msdn.com/nickmalik

Disclaimer: Opinions expressed in this forum are my own, and not
representative of my employer.
I do not answer questions on behalf of my employer. I'm just a
programmer helping programmers.
--