Classic ASP Requires Chilkat v11.0.0+
Generate a CSR with keyUsage, extKeyUsage, and other Extensions

Demonstrates how to generate a CSR containing a 1.2.840.113549.1.9.14 extensionRequest with the following extensions:
1.3.6.1.4.1.311.20.2 enrollCerttypeExtension
2.5.29.15 keyUsage
2.5.29.37 extKeyUsage
2.5.29.14 subjectKeyIdentifier
Chilkat Classic ASP Downloads

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

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

'  This example will generate a secp256r1 ECDSA key for the CSR.
set ecc = Server.CreateObject("Chilkat.Ecc")
set prng = Server.CreateObject("Chilkat.Prng")
set privKey = Server.CreateObject("Chilkat.PrivateKey")
success = ecc.GenKey("secp256r1",prng,privKey)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( "Failed to generate a new ECDSA private key.") & "</pre>"
    Response.End
End If

set csr = Server.CreateObject("Chilkat.Csr")

'  Add common CSR fields:
csr.CommonName = "mysubdomain.mydomain.com"
csr.Country = "GB"
csr.State = "Yorks"
csr.Locality = "York"
csr.Company = "Internet Widgits Pty Ltd"
csr.EmailAddress = "support@mydomain.com"

'  Add the following 1.2.840.113549.1.9.14 extensionRequest
'  Note: The easiest way to know the content and format of the XML to be added is to examine
'  a pre-existing CSR with the same desired extensionRequest.  You can use Chilkat to
'  get the extensionRequest from an existing CSR. 

'  Here is a sample extension request:

'  <?xml version="1.0" encoding="utf-8"?>
'  <set>
'      <sequence>
'          <sequence>
'              <oid>1.3.6.1.4.1.311.20.2</oid>
'              <asnOctets>
'                  <universal tag="30" constructed="0">AEUAbgBkAEUAbgB0AGkAdAB5AEMAbABpAGUAbgB0AEEAdQB0AGgAQwBlAHIAdABpAGYAaQBjAGEAdABl
'  AF8AQwBTAFIAUABhAHMAcwB0AGgAcgBvAHUAZwBoAC8AVgAx</universal>
'              </asnOctets>
'          </sequence>
'          <sequence>
'              <oid>2.5.29.15</oid>
'              <bool>1</bool>
'              <asnOctets>
'                  <bits n="3">A0</bits>
'              </asnOctets>
'          </sequence>
'          <sequence>
'              <oid>2.5.29.37</oid>
'              <asnOctets>
'                  <sequence>
'                      <oid>1.3.6.1.5.5.7.3.3</oid>
'                  </sequence>
'              </asnOctets>
'          </sequence>
'          <sequence>
'              <oid>2.5.29.14</oid>
'              <asnOctets>
'                  <octets>MCzBMQAViXBz8IDt8LsgmJxJ4Xg=</octets>
'              </asnOctets>
'          </sequence>
'      </sequence>
'  </set>

'  Use this online tool to generate code from sample XML: 
'  Generate Code to Create XML

'  A few notes:
'  The string "AEUAbgBkAEUAbgB0AGkAdAB5AEMAbABpAGUAbgB0AEEAdQB0AGgAQwBlAHIAdABpAGYAaQBjAGEAdABlAF8AQwBTAFIAUABhAHMAcwB0AGgAcgBvAHUAZwBoAC8AVgAx"
'  is the base64 encoding of the utf-16be byte representation of the string "EndEntityClientAuthCertificate_CSRPassthrough/V1"

s = "EndEntityClientAuthCertificate_CSRPassthrough/V1"
set bdTemp = Server.CreateObject("Chilkat.BinData")
success = bdTemp.AppendString(s,"utf-16be")
s_base64_utf16be = bdTemp.GetEncoded("base64")
'  The string should be "AEUA....."
Response.Write "<pre>" & Server.HTMLEncode( s_base64_utf16be) & "</pre>"

'  Here's the code to generate the above extension request.

set xml = Server.CreateObject("Chilkat.Xml")
xml.Tag = "set"
xml.UpdateChildContent "sequence|sequence|oid","1.3.6.1.4.1.311.20.2"
success = xml.UpdateAttrAt("sequence|sequence|asnOctets|universal",1,"tag","30")
success = xml.UpdateAttrAt("sequence|sequence|asnOctets|universal",1,"constructed","0")
xml.UpdateChildContent "sequence|sequence|asnOctets|universal",s_base64_utf16be
xml.UpdateChildContent "sequence|sequence[1]|oid","2.5.29.15"
xml.UpdateChildContent "sequence|sequence[1]|bool","1"
success = xml.UpdateAttrAt("sequence|sequence[1]|asnOctets|bits",1,"n","3")
'  A0 is hex for decimal 160.
xml.UpdateChildContent "sequence|sequence[1]|asnOctets|bits","A0"
xml.UpdateChildContent "sequence|sequence[2]|oid","2.5.29.37"
xml.UpdateChildContent "sequence|sequence[2]|asnOctets|sequence|oid","1.3.6.1.5.5.7.3.3"

'  This is the subjectKeyIdentifier extension.
'  The string "MCzBMQAViXBz8IDt8LsgmJxJ4Xg=" is base64 that decodes to 20 bytes, which is a SHA1 hash.
'  This is simply a hash of the DER of the public key.

set pubKey = Server.CreateObject("Chilkat.PublicKey")
success = privKey.ToPublicKey(pubKey)
set bdPubKeyDer = Server.CreateObject("Chilkat.BinData")
success = bdPubKeyDer.AppendEncoded(pubKey.GetEncoded(1,"base64"),"base64")
ski = bdPubKeyDer.GetHash("sha1","base64")

xml.UpdateChildContent "sequence|sequence[3]|oid","2.5.29.14"
xml.UpdateChildContent "sequence|sequence[3]|asnOctets|octets",ski

'  Add the extension request to the CSR
success = csr.SetExtensionRequest(xml)

'  Generate the CSR with the extension request
csrPem = csr.GenCsrPem(privKey)
If (csr.LastMethodSuccess = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( csr.LastErrorText) & "</pre>"
    Response.End
End If

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

%>
</body>
</html>