Classic ASP
AES Encrypt and Decrypt a File

_LANGUAGE_ demonstrates how to AES encrypt a file of any size, and then decrypt.
Chilkat Classic ASP Downloads

Classic ASP
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

set crypt = Server.CreateObject("Chilkat.Crypt2")

crypt.CryptAlgorithm = "aes"

'  CipherMode may be "ecb" or "cbc"
crypt.CipherMode = "cbc"

'  KeyLength may be 128, 192, 256
crypt.KeyLength = 256

'  The padding scheme determines the contents of the bytes
'  that are added to pad the result to a multiple of the
'  encryption algorithm's block size.  AES has a block
'  size of 16 bytes, so encrypted output is always
'  a multiple of 16.
crypt.PaddingScheme = 0

'  An initialization vector is required if using CBC mode.
'  ECB mode does not use an IV.
'  The length of the IV is equal to the algorithm's block size.
'  It is NOT equal to the length of the key.
ivHex = "000102030405060708090A0B0C0D0E0F"
crypt.SetEncodedIV ivHex,"hex"

'  The secret key must equal the size of the key.  For
'  256-bit encryption, the binary secret key is 32 bytes.
'  For 128-bit encryption, the binary secret key is 16 bytes.
keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
crypt.SetEncodedKey keyHex,"hex"

'  Encrypt a file, producing the .aes as output.
'  The input file is unchanged, the output .aes contains the encrypted
'  contents of the input file.

'  Note: The .aes output file has no file format.  It is simply a stream
'  of bytes that resembles random binary data.
inFile = "/Users/chilkat/testData/pdf/sample.pdf"
outFile = "/Users/chilkat/testData/p7m/sample.pdf.aes"
success = crypt.CkEncryptFile(inFile,outFile)
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( crypt.LastErrorText) & "</pre>"
    Response.End
End If

'  For demonstration purposes, a different instance of the object will be used
'  for decryption.
set decrypt = Server.CreateObject("Chilkat.Crypt2")

'  All settings must match to be able to decrypt:
decrypt.CryptAlgorithm = "aes"
decrypt.CipherMode = "cbc"
decrypt.KeyLength = 256
decrypt.PaddingScheme = 0
decrypt.SetEncodedIV ivHex,"hex"
decrypt.SetEncodedKey keyHex,"hex"

'  Decrypt the .aes
inFile = "/Users/chilkat/testData/p7m/sample.pdf.aes"
outFile = "/Users/chilkat/testData/pdf/recovered.pdf"
success = decrypt.CkDecryptFile(inFile,outFile)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( decrypt.LastErrorText) & "</pre>"
    Response.End
End If

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

%>
</body>
</html>