(Classic ASP) AES Encryption ECB Mode with PKCS7 Padding

Duplicates the following C# code:

public static byte[] DecryptBySymmetricKey(string encryptedText, byte[] key)
  {
     string keyAsBase64 = Convert.ToBase64String(key);

     byte[] dataToDecrypt = Convert.FromBase64String(encryptedText);
     var keyBytes = key;
     AesManaged tdes = new AesManaged();
     tdes.KeySize = 256;
     tdes.BlockSize = 128;
     tdes.Key = keyBytes;
     tdes.Mode = CipherMode.ECB;
     tdes.Padding = PaddingMode.PKCS7;
     ICryptoTransform decrypt__1 = tdes.CreateDecryptor();
     byte[] deCipher = decrypt__1.TransformFinalBlock(dataToDecrypt, 0, dataToDecrypt.Length);
     tdes.Clear();
     string EK_result = Convert.ToBase64String(deCipher);
     return EK_result;
}

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Crypt2")
set crypt = Server.CreateObject("Chilkat.Crypt2")

' In the C# code above that is to be duplicated here, use the base64 encoded key.
keyAsBase64 = "..."
encryptedBytesAsBase64 = "...."

crypt.KeyLength = 256
crypt.CryptAlgorithm = "AES"
crypt.CipherMode = "ecb"
crypt.PaddingScheme = 0
crypt.SetEncodedKey keyAsBase64,"base64"

crypt.EncodingMode = "base64"

' Pass the base64 representation of the encrypted data.
' (The EncodingMode indicates you are passing base64.)
EK_result = crypt.DecryptStringENC(encryptedBytesAsBase64)

Response.Write "<pre>" & Server.HTMLEncode( EK_result) & "</pre>"

%>
</body>
</html>