diff --git a/Cargo.lock b/Cargo.lock
index 879c9d6a89..e1bce963f6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -642,9 +642,9 @@ dependencies = [
 
 [[package]]
 name = "candid"
-version = "0.6.4"
+version = "0.6.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "27809afd71dc33263f06d5c0cd30d498710954adb8c6e4ae8330a818c644a32b"
+checksum = "3ccf4490c14ff64cac64a3b7dabc3cd7270ebc096eae12c745c3ad6882385198"
 dependencies = [
  "byteorder",
  "candid_derive",
diff --git a/src/dfx/Cargo.toml b/src/dfx/Cargo.toml
index b4c11fb253..f2f10e5a9e 100644
--- a/src/dfx/Cargo.toml
+++ b/src/dfx/Cargo.toml
@@ -21,7 +21,7 @@ actix-server = "1.0.3"
 actix-web = { version = "2.0.0", features = [ "default", "openssl", "rustls" ] }
 atty = "0.2.13"
 base64 = "0.11.0"
-candid = "0.6.4"
+candid = "0.6.6"
 chrono = "0.4.9"
 clap = "2.33.0"
 console = "0.7.7"
diff --git a/src/distributed/assetstorage.mo b/src/distributed/assetstorage.mo
index eb6fa747e3..73c2f73ed3 100644
--- a/src/distributed/assetstorage.mo
+++ b/src/distributed/assetstorage.mo
@@ -1,37 +1,34 @@
-import AssocList "mo:base/AssocList";
 import Error "mo:base/Error";
-import List "mo:base/List";
-import Prim "mo:prim";
+import Tree "mo:base/RBTree";
+import Text "mo:base/Text";
+import Iter "mo:base/Iter";
 
-actor {
+shared {caller = creator} actor class () {
 
     public type Path = Text;
-
     public type Contents = Blob;
 
-    private let initializer : Principal = Prim.caller();
-
-    private stable var db: AssocList.AssocList<Path, Contents> = List.nil();
+    let initializer : Principal = creator;
 
-    func eq(a: Path, b: Path): Bool {
-        return a == b;
-    };
+    let db: Tree.RBTree<Path, Contents> = Tree.RBTree(Text.compare);
 
     public shared { caller } func store(path : Path, contents : Contents) : async () {
         if (caller != initializer) {
             throw Error.reject("not authorized");
         } else {
-            db := AssocList.replace<Path, Contents>(db, path, eq, ?contents).0;
+            db.put(path, contents);
         };
     };
 
     public query func retrieve(path : Path) : async Contents {
-        let result = AssocList.find<Path, Contents>(db, path, eq);
-        switch result {
-            case null {
-                throw Error.reject("not found");
-            };
-            case (?contents) contents;
+        switch (db.get(path)) {
+        case null throw Error.reject("not found");
+        case (?contents) contents;
         };
     };
+
+    public query func list() : async [Path] {
+        let iter = Iter.map<(Path, Contents), Path>(db.entries(), func (path, _) = path);
+        Iter.toArray(iter)
+    };
 };