Using longer and mixed case passwords

src/org/kde/kdeconnect/Helpers/RandomHelper.java

@@ -0,0 +1,24 @@
+package org.kde.kdeconnect.Helpers;
+
+
+import android.util.Log;
+
+import java.security.SecureRandom;
+
+public class RandomHelper {
+    public static SecureRandom secureRandom = new SecureRandom();
+
+    private static final char[] symbols = ("ABCDEFGHIJKLMNOPQRSTUVWXYZ"+
+                                           "abcdefghijklmnopqrstuvwxyz"+
+                                           "1234567890").toCharArray();
+
+
+    public static String randomString(int length) {
+        char[] buffer= new char[length];
+        for (int idx = 0; idx < length; ++idx) {
+            buffer[idx] = symbols[secureRandom.nextInt(symbols.length)];
+        }
+        return new String(buffer);
+    }
+
+}

src/org/kde/kdeconnect/Plugins/SftpPlugin/SftpImpl.java

@@ -39,6 +39,7 @@ import org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider;
 import org.apache.sshd.server.session.ServerSession;
 import org.apache.sshd.server.sftp.SftpSubsystem;
 import org.kde.kdeconnect.Device;
+import org.kde.kdeconnect.Helpers.RandomHelper;
 
 import java.io.File;
 import java.net.Inet4Address;
@@ -123,7 +124,8 @@ class SimpleSftpServer {
 
     public boolean start() {
         if (!started) {
-            String password = Long.toHexString(Double.doubleToLongBits(Math.random()));
+
+            String password = RandomHelper.randomString(28);
             passwordAuth.setPassword(password);
 
             port = STARTPORT;