Question

Hi i am using the following code to parse a certificate details.Everything is fine except a bit problem mentioned below.

package android.net.http;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileReader;
import java.io.InputStream;
import java.security.cert.Certif`enter code here`icate;
import java.security.cert.CertificateFactory;
import java.security.cert.CertificateParsingException;
import java.security.cert.X509Certificate;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Base64;
import android.util.Base64InputStream;
import android.util.Log;

 public class SslCertificate1Activity extends Activity
 {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);

try  {
String text = "-----BEGIN CERTIFICATE-----\n"+
    "MIIC/TCCAmagAwIBAgIBKjANBgkqhkiG9w0BAQQFADCBqDEiMCAGA1UEAxMZeG1sZ2F0ZXdheS5p\n"+
    "dHMudXRleGFzLmVkdTEoMCYGA1UECxMfSW5mb3JtYXRpb24gVGVjaG5vbG9neSBTZXJ2aWNlczEq\n"+
    "MCgGA1UEChMhVGhlIFVuaXZlcnNpdHkgb2YgVGV4YXMgYXQgQXVzdGluMQ8wDQYDVQQHEwZBdXN0\n"+
    "aW4xDjAMBgNVBAgTBVRleGFzMQswCQYDVQQGEwJVUzAeFw0wNDA1MDkwNTMwMTBaFw0wNTA1MDQw\n"+
    "NTMwMTBaMIGAMQswCQYDVQQGEwJVUzEOMAwGA1UECBMFVGV4YXMxDzANBgNVBAcTBkF1c3RpbjEq\n"+
    "MCgGA1UEChMhVGhlIFVuaXZlcnNpdHkgb2YgVGV4YXMgYXQgQXVzdGluMRMwEQYDVQQLEwpUb29s\n"+
    "cyBUZWFtMQ8wDQYDVQQDEwZDbGllbnQwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAJ6PABjb\n"+
    "zXUkgo29S4uv1Qz9reo1/tP4pkQTGAldSbtA4hVtA/3sjw2+u3kgxYruAi2cXV2k0RPZhsUZjlDk\n"+
    "jMPb/dlY81bD8gqe3lu3ezugJrlArlpfWN6PlufbTjxHSqIA0XD9R5/ZECaUV9dD43K5KdWUCy99\n"+
    "YKDiSwVPO9F5AgMBAAGjXTBbMB0GA1UdDgQWBBRkCCpscEXxXu8Ba67p6zdh13ypjzAfBgNVHSME\n"+
    "GDAWgBR2RsZH2kSY782kBROo92FAWS6sADAJBgNVHRMEAjAAMA4GA1UdDwQHAwUBEiRIkDANBgkq\n"+
    "hkiG9w0BAQQFAAOBgQCtV1NzpdVBs5vyb8yLXNA3hA1LsmE/2QanXG4T3UN93BI4HQzx0idnkN1Y\n"+
    "0RAQ1rjGeQ1pk3l2DWsPi9mTkCGmYs/EMLkKOBee9ad3BIG6sKwXgbgLyNLgda+Y1bo+SIomq/a7\n"+
    "yP92UHMFEegfS/ssECA+Q3hHuU6in3AqLfWH1w==\n"+
    "-----END CERTIFICATE-----";
int startIndex = 0;
String cert = text.substring(startIndex,text.length()); 
    byte[] certBytes = cert.getBytes();
    InputStream in = new Base64InputStream(new ByteArrayInputStream(
            certBytes), 0);
CertificateFactory certFact = CertificateFactory.getInstance ("X.509");
    Certificate certGen = certFact.generateCertificate(in); 
    X509Certificate x509 = (X509Certificate) certGen; 
     Log.i("","certificate details:"+x509);
    } 
    catch (Exception e)  
    {
        Log.e("testapp", "exception: " + e.getMessage()); 
    }  
}
 }

and I am getting android.util.BASE64DataException:bad base-64 at the foloowing line when I launced debugger:-

Certificate certGen = certFact.generateCertificate(in);

Seems like there is something wrong with Base64InputStream.Please help in rectifying the Exception.
Thanks in advance

Answer 1

No, nothing is wrong with Base64InputStream. When in doubt, you should suspect your own code of being incorrect rather than everyone else’s.

What’s wrong is that you’re giving Base64InputStream data that ends with “—–END CERTIFICATE—–” after the padding part.

You should only be passing in the bit between “—–BEGIN CERTIFICATE—–” and “—–END CERTIFICATE—–“.

It looks like you’ve started thinking about that already here:

int startIndex = 0;
String cert = text.substring(startIndex,text.length()); 

… but that code isn’t going to do anything – when startIndex is 0, substring is going to return the whole string…

Personally I’d consider doing the Base64 conversion first using the Base64 class to convert the base64 part of the string (you still need to get the substring) to a byte[] and then create a ByteArrayInputStream around that.