Obtener huella digital del certificado de la aplicación de Android

Question

¿Cómo obtener la huella del certificado de la aplicación desde el interior de esta aplicación? Quiero verificar si la aplicación está chamuscada con mi propio certificado o si fue reenvasado/pirateado.

Encontré parte de la solución aquí: Get Certificate from Android Application. Entonces la pregunta ahora es: cómo verificar la huella dactilar del certificado.

Answer 1

lo puse aquí - la función da el mismo resultado que keytool lo hace.

private String getCertificateSHA1Fingerprint() { 
    PackageManager pm = mContext.getPackageManager(); 
    String packageName = mContext.getPackageName(); 
    int flags = PackageManager.GET_SIGNATURES; 
    PackageInfo packageInfo = null; 
    try { 
     packageInfo = pm.getPackageInfo(packageName, flags); 
    } catch (PackageManager.NameNotFoundException e) { 
     e.printStackTrace(); 
    } 
    Signature[] signatures = packageInfo.signatures; 
    byte[] cert = signatures[0].toByteArray(); 
    InputStream input = new ByteArrayInputStream(cert); 
    CertificateFactory cf = null; 
    try { 
     cf = CertificateFactory.getInstance("X509"); 
    } catch (CertificateException e) { 
     e.printStackTrace(); 
    } 
    X509Certificate c = null; 
    try { 
     c = (X509Certificate) cf.generateCertificate(input); 
    } catch (CertificateException e) { 
     e.printStackTrace(); 
    } 
    String hexString = null; 
    try { 
     MessageDigest md = MessageDigest.getInstance("SHA1"); 
     byte[] publicKey = md.digest(c.getEncoded()); 
     hexString = byte2HexFormatted(publicKey); 
    } catch (NoSuchAlgorithmException e1) { 
     e1.printStackTrace(); 
    } catch (CertificateEncodingException e) { 
     e.printStackTrace(); 
    } 
    return hexString; 
} 

public static String byte2HexFormatted(byte[] arr) { 
    StringBuilder str = new StringBuilder(arr.length * 2); 
    for (int i = 0; i < arr.length; i++) { 
     String h = Integer.toHexString(arr[i]); 
     int l = h.length(); 
     if (l == 1) h = "0" + h; 
     if (l > 2) h = h.substring(l - 2, l); 
     str.append(h.toUpperCase()); 
     if (i < (arr.length - 1)) str.append(':'); 
    } 
    return str.toString(); 
} 

Answer 2

Disculpa, fui más rápido debajo de mi solución, gracias por tu tiempo;

import java.io.ByteArrayInputStream; 
import java.io.InputStream; 
import java.security.MessageDigest; 
import java.security.NoSuchAlgorithmException; 
import java.security.cert.CertificateException; 
import java.security.cert.CertificateFactory; 
import java.security.cert.X509Certificate; 
import android.app.Activity; 
import android.content.pm.PackageInfo; 
import android.content.pm.PackageManager; 
import android.content.pm.PackageManager.NameNotFoundException; 
import android.content.pm.Signature; 
import android.os.Bundle; 
import android.util.Log; 

public class MainActivity extends Activity { 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 

      PackageManager pm = this.getPackageManager(); 
      String packageName = this.getPackageName(); 
      int flags = PackageManager.GET_SIGNATURES; 

      PackageInfo packageInfo = null; 

      try { 
        packageInfo = pm.getPackageInfo(packageName, flags); 
      } catch (NameNotFoundException e) { 
        e.printStackTrace(); 
      } 
      Signature[] signatures = packageInfo.signatures; 

      byte[] cert = signatures[0].toByteArray(); 

      InputStream input = new ByteArrayInputStream(cert); 

      CertificateFactory cf = null; 
      try { 
        cf = CertificateFactory.getInstance("X509"); 


      } catch (CertificateException e) { 
        e.printStackTrace(); 
      } 
      X509Certificate c = null; 
      try { 
        c = (X509Certificate) cf.generateCertificate(input); 
      } catch (CertificateException e) { 
        e.printStackTrace(); 
      } 


      try { 
       MessageDigest md = MessageDigest.getInstance("SHA1"); 
       byte[] publicKey = md.digest(c.getPublicKey().getEncoded()); 


       StringBuffer hexString = new StringBuffer(); 
       for (int i=0;i<publicKey.length;i++) { 
        String appendString = Integer.toHexString(0xFF & publicKey[i]); 
        if(appendString.length()==1)hexString.append("0"); 
        hexString.append(appendString); 
        } 


       Log.d("Example", "Cer: "+ hexString.toString()); 

      } catch (NoSuchAlgorithmException e1) { 
       e1.printStackTrace(); 
      } 

    } 
}