Check signature

app/src/main/java/eu/faircode/email/ActivityView.java

@@ -368,7 +368,11 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
 
                     sb.append(context.getString(R.string.title_crash_info_remark) + "\n\n\n\n");
 
-                    sb.append(String.format("%s: %s\r\n", context.getString(R.string.app_name), BuildConfig.VERSION_NAME));
+                    sb.append(String.format("%s: %s %s/%s\r\n",
+                            context.getString(R.string.app_name),
+                            BuildConfig.APPLICATION_ID,
+                            BuildConfig.VERSION_NAME,
+                            Helper.hasValidFingerprint(context) ? "1" : "3"));
                     sb.append(String.format("Android: %s (SDK %d)\r\n", Build.VERSION.RELEASE, Build.VERSION.SDK_INT));
                     sb.append("\r\n");
 

app/src/main/java/eu/faircode/email/FragmentAbout.java

@@ -88,7 +88,11 @@ public class FragmentAbout extends FragmentEx {
                         sb.append(context.getString(R.string.title_debug_info_remark) + "\n\n\n\n");
 
                         // Get version info
-                        sb.append(String.format("%s: %s\r\n", context.getString(R.string.app_name), BuildConfig.VERSION_NAME));
+                        sb.append(String.format("%s: %s %s/%s\r\n",
+                                context.getString(R.string.app_name),
+                                BuildConfig.APPLICATION_ID,
+                                BuildConfig.VERSION_NAME,
+                                Helper.hasValidFingerprint(context) ? "1" : "3"));
                         sb.append(String.format("Android: %s (SDK %d)\r\n", Build.VERSION.RELEASE, Build.VERSION.SDK_INT));
                         sb.append("\r\n");
 
@@ -250,8 +254,8 @@ public class FragmentAbout extends FragmentEx {
         });
 
         boolean debug = PreferenceManager.getDefaultSharedPreferences(getContext()).getBoolean("debug", false);
-        btnLog.setVisibility(debug ? View.VISIBLE : View.GONE);
-        btnDebugInfo.setVisibility(debug ? View.VISIBLE : View.GONE);
+        btnLog.setVisibility(debug || BuildConfig.DEBUG ? View.VISIBLE : View.GONE);
+        btnDebugInfo.setVisibility(debug || BuildConfig.DEBUG ? View.VISIBLE : View.GONE);
 
         return view;
     }

app/src/main/java/eu/faircode/email/Helper.java

@@ -23,6 +23,8 @@ import android.accounts.Account;
 import android.accounts.AccountManager;
 import android.content.Context;
 import android.content.Intent;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
 import android.content.res.TypedArray;
 import android.net.Uri;
 import android.preference.PreferenceManager;
@@ -328,6 +330,30 @@ public class Helper {
         }
     }
 
+    public static String getFingerprint(Context context) {
+        try {
+            PackageManager pm = context.getPackageManager();
+            String pkg = context.getPackageName();
+            PackageInfo info = pm.getPackageInfo(pkg, PackageManager.GET_SIGNATURES);
+            byte[] cert = info.signatures[0].toByteArray();
+            MessageDigest digest = MessageDigest.getInstance("SHA1");
+            byte[] bytes = digest.digest(cert);
+            StringBuilder sb = new StringBuilder();
+            for (byte b : bytes)
+                sb.append(Integer.toString(b & 0xff, 16).toUpperCase());
+            return sb.toString();
+        } catch (Throwable ex) {
+            Log.e(TAG, ex.toString() + "\n" + Log.getStackTraceString(ex));
+            return null;
+        }
+    }
+
+    public static boolean hasValidFingerprint(Context context) {
+        String signed = getFingerprint(context);
+        String expected = context.getString(R.string.fingerprint);
+        return (signed != null && signed.equals(expected));
+    }
+
     static boolean isPro(Context context) {
         if (false && BuildConfig.DEBUG)
             return true;

app/src/main/res/values/strings.xml

@@ -302,4 +302,6 @@
         <item>@color/grey</item>
         <item>@color/dark_grey</item>
     </array>
+
+    <string name="fingerprint" translatable="false">17BA15C1AF55D925F98B99CEA4375D4CDF4C174B</string>
 </resources>