C

Duplicate Java Verify RSA Signature

See more RSA Examples

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

#include <C_CkCert.h>
#include <C_CkRsa.h>

void ChilkatSample(void)
    {
    BOOL success;
    const char *base64DataToBeSigned;
    const char *base64Certificate;
    const char *base64Signature;
    HCkCert cert;
    HCkRsa rsa;

    success = FALSE;

    // 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==";

    cert = CkCert_Create();
    success = CkCert_LoadFromBase64(cert,base64Certificate);
    if (success == FALSE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkCert_Dispose(cert);
        return;
    }

    rsa = CkRsa_Create();

    success = CkRsa_SetX509Cert(rsa,cert,FALSE);
    if (success == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkCert_Dispose(cert);
        CkRsa_Dispose(rsa);
        return;
    }

    CkRsa_putEncodingMode(rsa,"base64");
    success = CkRsa_VerifyStringENC(rsa,base64DataToBeSigned,"sha256",base64Signature);
    if (success == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkCert_Dispose(cert);
        CkRsa_Dispose(rsa);
        return;
    }

    printf("Signature verified.\n");


    CkCert_Dispose(cert);
    CkRsa_Dispose(rsa);

    }