Classic ASP

Set the S/MIME Encryption Key Length

Demonstrates the Chilkat Email.Pkcs7KeyLength property, which sets the key length of the symmetric algorithm used for PKCS#7 (S/MIME) encryption. The allowed values depend on Pkcs7CryptAlg: for aes use 128, 192, or 256; for 3des use 192; for des use 40; for rc2 use 40, 56, 64, or 128. The default is 128, and an unsupported algorithm/key-length combination causes encryption to fail. This example pairs AES with a 192-bit key.

Background: Key length is the size, in bits, of the secret key a symmetric cipher uses — a longer key means exponentially more possible keys and thus more resistance to brute-force attack. But length is only meaningful within a given algorithm: AES-128 is already very strong, and a key size must be one the chosen cipher actually supports, which is why Pkcs7KeyLength and Pkcs7CryptAlg have to agree.

Chilkat Classic ASP Downloads

Download Chilkat for Classic ASP

Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
'  Demonstrates the Email.Pkcs7KeyLength property, which sets the key length (in bits)
'  of the symmetric algorithm used for PKCS#7 (S/MIME) encryption.  The allowed values
'  depend on Pkcs7CryptAlg; for aes they are 128, 192, or 256.  The default is 128.

set email = Server.CreateObject("Chilkat.Email")

email.Pkcs7CryptAlg = "aes"
email.Pkcs7KeyLength = 192

Response.Write "<pre>" & Server.HTMLEncode( "Pkcs7CryptAlg = " & email.Pkcs7CryptAlg) & "</pre>"
Response.Write "<pre>" & Server.HTMLEncode( "Pkcs7KeyLength = " & email.Pkcs7KeyLength) & "</pre>"

%>
</body>
</html>