(Classic ASP) Convert RSA Private Key to Public Key

Demonstrates how to get a public RSA key from a private RSA key.

Note: This example requires Chilkat v11.0.0 or greater.

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>
<%
success = 0

set privKey = Server.CreateObject("Chilkat.PrivateKey")

' Step 1: Load the private key from a source.
' (Chilkat can load private keys from all types of formats, and from in-memory bytes or encoded strings.
' see the online reference documentation for more options.)
success = privKey.LoadPemFile("qa_data/pem/VP_Private.pem")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( privKey.LastErrorText) & "</pre>"
    Response.End
End If

' Step 2: Get the public key object from the private key object.
set pubKey = Server.CreateObject("Chilkat.PublicKey")
success = privKey.ToPublicKey(pubKey)

' Step 3: Save the public key in a desired format. 
' (Chilkat can load or save public and private keys in many different formats.  See
' the online reference documentation for more options.)

' Saves to a PKCS8 PEM file.
bPreferPkcs1 = 0
success = pubKey.SavePemFile(bPreferPkcs1,"qa_data/pem/VP_Public.pem")
If (pubKey.LastMethodSuccess = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( pubKey.LastErrorText) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "Extracted and saved public key from private key.") & "</pre>"

%>
</body>
</html>