SmartFrameworkSecurity.java

package com.smart.framework;

import android.content.Context;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;

import java.io.ByteArrayInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

import javax.security.auth.x500.X500Principal;

public class SmartFrameworkSecurity {

    private Context context;
    private PackageManager packageManager;

    public SmartFrameworkSecurity(Context context) {
        this.context = context;
    }

    public boolean matchKey(String key) {
        return ((md5(getApplicationSignature()).equals(key)) ? true : false);
    }

    private String getApplicationSignature() {
        String strSignature = "";
        packageManager = context.getPackageManager();
        try {
            Signature[] signs = packageManager.getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES).signatures;
            for (Signature signature : signs) {
//                Log.d("Test Signature = ", "sign = " + signature.toCharsString());
                strSignature = signature.toCharsString();
            }
        } catch (NameNotFoundException e) {
            e.printStackTrace();
        }

        return strSignature;

    }

    public boolean isDebugKey() {
        boolean debug = false;
        X500Principal DEBUG_DN = new X500Principal("CN=Android Debug,O=Android,C=US");
        /* ... */
        Signature raw;
        try {
            raw = packageManager.getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES).signatures[0];
            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            X509Certificate cert = (X509Certificate) cf.generateCertificate(new ByteArrayInputStream(raw.toByteArray()));
            debug = cert.getSubjectX500Principal().equals(DEBUG_DN);

//	        Log.d("Test Signature = ", "sign = " + ((debug) ? "YES" : "NO"));

        } catch (NameNotFoundException e) {
            e.printStackTrace();
        } catch (CertificateException e) {
            e.printStackTrace();
        }

        return debug;
    }

    private String md5(String s) {
        try {
            // Create MD5 Hash
            MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
            digest.update(s.getBytes());
            byte messageDigest[] = digest.digest();

            // Create Hex String
            StringBuffer hexString = new StringBuffer();
            for (int i = 0; i < messageDigest.length; i++)
                hexString.append(Integer.toHexString(0xFF & messageDigest[i]));
            return hexString.toString();

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }

}