(Visual FoxPro) Duplicate Java Verify RSA Signature

Demonstrates how to duplicate a snippet of Java code that verifies an RSA signature.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL lcBase64DataToBeSigned
LOCAL lcBase64Certificate
LOCAL lcBase64Signature
LOCAL loCert
LOCAL lnSuccess
LOCAL loRsa

* 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);  
*     }  
* } 

lcBase64DataToBeSigned = "Hlp...LE4="
lcBase64Certificate = "MII...TlQ=="
lcBase64Signature = "I00...pZA=="

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Cert')
loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadFromBase64(lcBase64Certificate)
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loCert
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rsa')
loRsa = CreateObject('Chilkat.Rsa')

lnSuccess = loRsa.SetX509Cert(loCert,0)
IF (lnSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loCert
    RELEASE loRsa
    CANCEL
ENDIF

loRsa.EncodingMode = "base64"
lnSuccess = loRsa.VerifyStringENC(lcBase64DataToBeSigned,"sha256",lcBase64Signature)
IF (lnSuccess = 0) THEN
    ? loRsa.LastErrorText
    RELEASE loCert
    RELEASE loRsa
    CANCEL
ENDIF

? "Signature verified."

RELEASE loCert
RELEASE loRsa