(Classic ASP) Convert RSA Private Key to Public Key

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

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

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<%
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.PrivateKey")
set key = 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 = key.LoadPemFile("qa_data/pem/VP_Private.pem")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( key.LastErrorText) & "</pre>"
    Response.End
End If

' Step 2: Get the public key object from the private key object.
' pubKey is a Chilkat.PublicKey
Set pubKey = key.GetPublicKey()
If (key.LastMethodSuccess <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( key.LastErrorText) & "</pre>"
    Response.End
End If

' 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 <> 1) 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>"

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