Classic ASP
Duplicate Java Verify RSA Signature

Demonstrates how to duplicate a snippet of Java code that verifies an RSA signature.
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 duplicates the following Java code:

' import com.sun.org.apache.xml.internal.security.utils.Base64;  
' import java.io.ByteArrayInputStream;  
' import java.security.PublicKey;  
' import java.security.Signature;  
' import java.security.cert.CertificateFactory;  
' import java.security.cert.X509Certificate;  
' public class validateSazetak {  
'   public static void main(String[] args) {  
'   String signatureAlgorithm = "SHA256withRSA";  
'   String base64DataToBeSigned = "Hlp...LE4=";  
'   String base64Certificate = "MII...TlQ==";  
'   String base64Signature = "I00...pZA==";  
'   try {  
'       CertificateFactory cf;  
'       X509Certificate certificate = null;  
'       cf = CertificateFactory.getInstance("X.509");  
'       certificate = (X509Certificate) cf.generateCertificate(new 
'       ByteArrayInputStream(Base64.decode(base64Certificate)));  
'        
'       Signature signature = Signature.getInstance(signatureAlgorithm, "SunRsaSign");  
'       PublicKey pk = (PublicKey) certificate.getPublicKey();  
'       signature.initVerify(pk);  
'        
'       byte[] hashBytes = Base64.decode(base64DataToBeSigned);  
'       signature.update(hashBytes);  
'        
'       byte[] sigBytes = Base64.decode(base64Signature);  
'       boolean validity = signature.verify(sigBytes);  
'       System.out.println("Is valid signature:" + validity);  
'     } catch (Exception e) {  
'         System.out.println(e);  
'     }  
' } 

base64DataToBeSigned = "Hlp...LE4="
base64Certificate = "MII...TlQ=="
base64Signature = "I00...pZA=="

set cert = Server.CreateObject("Chilkat.Cert")
success = cert.LoadFromBase64(base64Certificate)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( cert.LastErrorText) & "</pre>"
    Response.End
End If

set rsa = Server.CreateObject("Chilkat.Rsa")

success = rsa.SetX509Cert(cert,0)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.End
End If

rsa.EncodingMode = "base64"
success = rsa.VerifyStringENC(base64DataToBeSigned,"sha256",base64Signature)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.End
End If

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

%>
</body>
</html>