diff --git a/src/org/geometerplus/android/fbreader/network/AuthenticationActivity.java b/src/org/geometerplus/android/fbreader/network/AuthenticationActivity.java
index 61000ef8d..4685cb57e 100644
--- a/src/org/geometerplus/android/fbreader/network/AuthenticationActivity.java
+++ b/src/org/geometerplus/android/fbreader/network/AuthenticationActivity.java
@@ -74,7 +74,7 @@ public class AuthenticationActivity extends Activity {
 		}
 	}
 
-	static class CredentialsCreator extends ZLNetworkManager.BasicCredentialsCreator {
+	static class CredentialsCreator extends ZLNetworkManager.CredentialsCreator {
 		private final Context myContext;
 
 		CredentialsCreator(Context context) {
@@ -210,8 +210,8 @@ public class AuthenticationActivity extends Activity {
 	private void finishOk(String username, String password) {
 		final ZLNetworkManager.CredentialsCreator creator =
 			ZLNetworkManager.Instance().getCredentialsCreator();
-		if (creator instanceof CredentialsCreator) {
-			((CredentialsCreator)creator).setCredentials(username, password);
+		if (creator != null) {
+			creator.setCredentials(username, password);
 		}
 		finish();
 	}
@@ -280,8 +280,8 @@ public class AuthenticationActivity extends Activity {
 	protected void onStop() {
 		final ZLNetworkManager.CredentialsCreator creator =
 			ZLNetworkManager.Instance().getCredentialsCreator();
-		if (creator instanceof CredentialsCreator) {
-			((CredentialsCreator)creator).release();
+		if (creator != null) {
+			creator.release();
 		}
 		super.onStop();
 	}
diff --git a/src/org/geometerplus/zlibrary/core/network/ZLNetworkManager.java b/src/org/geometerplus/zlibrary/core/network/ZLNetworkManager.java
index 1c1c43874..b458a34d7 100644
--- a/src/org/geometerplus/zlibrary/core/network/ZLNetworkManager.java
+++ b/src/org/geometerplus/zlibrary/core/network/ZLNetworkManager.java
@@ -52,11 +52,7 @@ public class ZLNetworkManager {
 		return ourManager;
 	}
 
-	public static interface CredentialsCreator {
-		Credentials createCredentials(String scheme, AuthScope scope);
-	}
-
-	public static abstract class BasicCredentialsCreator implements ZLNetworkManager.CredentialsCreator {
+	public static abstract class CredentialsCreator {
 		private volatile String myUsername;
 		private volatile String myPassword;
 
@@ -71,7 +67,9 @@ public class ZLNetworkManager {
 		}
 
 		public Credentials createCredentials(String scheme, AuthScope scope) {
-			if (!"basic".equalsIgnoreCase(scope.getScheme())) {
+			final String authScheme = scope.getScheme();
+			if (!"basic".equalsIgnoreCase(authScheme) &&
+				!"digest".equalsIgnoreCase(authScheme)) {
 				return null;
 			}