update display of signing key fingerprint

Update Utils.formatFingerprint() to create a more readible version of the
SHA-256 fingerprint of the signing key of the repo.

res/values/strings.xml

@@ -168,7 +168,7 @@
     <string name="unsigned">Unsigned</string>
     <string name="repo_url">URL</string>
     <string name="repo_num_apps">Number of apps</string>
-    <string name="repo_fingerprint">Fingerprint of Repo Signing Key (SHA1)</string>
+    <string name="repo_fingerprint">Fingerprint of Repo Signing Key (SHA-256)</string>
     <string name="repo_description">Description</string>
     <string name="repo_last_update">Last update</string>
     <string name="repo_update">Update</string>

src/org/fdroid/fdroid/Utils.java

@@ -18,26 +18,20 @@
 
 package org.fdroid.fdroid;
 
-import android.os.Build;
+import android.content.Context;
-import android.util.Log;
+
+import com.nostra13.universalimageloader.utils.StorageUtils;
 
 import java.io.BufferedReader;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileReader;
-import java.io.InputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 import java.text.SimpleDateFormat;
-import java.security.MessageDigest;
-import java.util.Formatter;
 import java.util.Locale;
 
-import android.content.Context;
-
-import com.nostra13.universalimageloader.utils.StorageUtils;
-import org.fdroid.fdroid.data.Repo;
-
 public final class Utils {
 
     public static final int BUFFER_SIZE = 4096;
@@ -48,8 +42,6 @@ public final class Utils {
     public static final SimpleDateFormat LOG_DATE_FORMAT =
             new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ENGLISH);
 
-
-
     public static void copy(InputStream input, OutputStream output)
             throws IOException {
         copy(input, output, null, null);
@@ -160,36 +152,16 @@ public final class Utils {
         return count;
     }
 
-    public static String formatFingerprint(Repo repo) {
+    // return a fingerprint formatted for display
-        return formatFingerprint(repo.pubkey);
+    public static String formatFingerprint(String fingerprint) {
+        if (fingerprint.length() != 62)  // SHA-256 is 62 hex chars
+            return "BAD FINGERPRINT";
+        String displayFP = fingerprint.substring(0, 2);
+        for (int i = 2; i < fingerprint.length(); i = i + 2)
+            displayFP += " " + fingerprint.substring(i, i + 2);
+        return displayFP;
     }
 
-    public static String formatFingerprint(String key) {
-        String fingerprintString;
-        if (key == null) {
-            return "";
-        }
-
-        try {
-            MessageDigest digest = MessageDigest.getInstance("SHA-1");
-            digest.update(Hasher.unhex(key));
-            byte[] fingerprint = digest.digest();
-            Formatter formatter = new Formatter(new StringBuilder());
-            formatter.format("%02X", fingerprint[0]);
-            for (int i = 1; i < fingerprint.length; i++) {
-                formatter.format(i % 5 == 0 ? " %02X" : ":%02X",
-                        fingerprint[i]);
-            }
-            fingerprintString = formatter.toString();
-            formatter.close();
-        } catch (Exception e) {
-            Log.w("FDroid", "Unable to get certificate fingerprint.\n"
-                    + Log.getStackTraceString(e));
-            fingerprintString = "";
-        }
-        return fingerprintString;
-    }
-    
     public static File getApkCacheDir(Context context) {
         File apkCacheDir = new File(
                 StorageUtils.getCacheDirectory(context, true), "apks");

src/org/fdroid/fdroid/views/fragments/RepoDetailsFragment.java

@@ -8,6 +8,7 @@ import android.os.Bundle;
 import android.support.v4.app.Fragment;
 import android.support.v4.view.MenuItemCompat;
 import android.text.Editable;
+import android.text.TextUtils;
 import android.text.TextWatcher;
 import android.util.Log;
 import android.view.*;
@@ -286,15 +287,17 @@ public class RepoDetailsFragment extends Fragment {
         String repoFingerprint;
         int repoFingerprintColor;
 
-        if (repo.pubkey != null && repo.pubkey.length() > 0) {
+// TODO show the current state of the signature check, not just whether there is a key or not
-            repoFingerprint       = Utils.formatFingerprint(repo.pubkey);
+        if (TextUtils.isEmpty(repo.fingerprint) && TextUtils.isEmpty(repo.pubkey)) {
-            repoFingerprintColor = getResources().getColor(R.color.signed);
+            repoFingerprint = getResources().getString(R.string.unsigned);
-            repoFingerprintDescView.setVisibility(View.GONE);
-        } else {
-            repoFingerprint       = getResources().getString(R.string.unsigned);
             repoFingerprintColor = getResources().getColor(R.color.unsigned);
             repoFingerprintDescView.setVisibility(View.VISIBLE);
             repoFingerprintDescView.setText(getResources().getString(R.string.unsigned_description));
+        } else {
+            // this is based on repo.fingerprint always existing, which it should
+            repoFingerprint = Utils.formatFingerprint(repo.fingerprint);
+            repoFingerprintColor = getResources().getColor(R.color.signed);
+            repoFingerprintDescView.setVisibility(View.GONE);
         }
 
         repoFingerprintView.setText(repoFingerprint);