Checking key usage is experimental

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

@@ -4353,6 +4353,7 @@ public class FragmentCompose extends FragmentBase {
                 SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
                 boolean check_certificate = prefs.getBoolean("check_certificate", true);
                 boolean check_key_usage = prefs.getBoolean("check_key_usage", false);
+                boolean experiments = prefs.getBoolean("experiments", false);
 
                 File tmp = Helper.ensureExists(context, "encryption");
 
@@ -4421,7 +4422,7 @@ public class FragmentCompose extends FragmentBase {
                     try {
                         chain[0].checkValidity();
 
-                        if (check_key_usage) {
+                        if (check_key_usage && experiments) {
                             // Signing Key: Key Usage: Digital Signature, Non-Repudiation
                             // Encrypting Key: Key Usage: Key Encipherment, Data Encipherment
 

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

@@ -195,6 +195,7 @@ public class FragmentOptionsEncryption extends FragmentBase
         // Wire controls
 
         final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
+        boolean experiments = prefs.getBoolean("experiments", false);
 
         ibHelp.setOnClickListener(new View.OnClickListener() {
             @Override
@@ -401,6 +402,7 @@ public class FragmentOptionsEncryption extends FragmentBase
             }
         });
 
+        swCheckKeyUsage.setVisibility(experiments ? View.VISIBLE : View.GONE);
         swCheckKeyUsage.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {

app/src/main/res/layout/fragment_options_encryption.xml

@@ -427,7 +427,6 @@
                     android:layout_height="wrap_content"
                     android:layout_marginStart="12dp"
                     android:layout_marginTop="12dp"
-                    android:checked="true"
                     android:text="@string/title_advanced_check_key_usage"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"