diff --git a/red/runtime/locales/en-US/runtime.json b/red/runtime/locales/en-US/runtime.json
index 6e9f057ae..f7a4b8a3d 100644
--- a/red/runtime/locales/en-US/runtime.json
+++ b/red/runtime/locales/en-US/runtime.json
@@ -155,5 +155,16 @@
                 "readme": "### About\n\nThis is your project's README.md file. It helps users understand what your\nproject does, how to use it and anything else they may need to know."
             }
         }
+    },
+
+    "context": {
+        "error-module-not-loaded": "'__module__' could not be loaded",
+        "error-module-not-defined": "'module' is not defined in '__storage__' of settings.contextStorage",
+        "error-invalid-default-module": "Invalid storage '__storage__' is specified as a default storage",
+        "error-key-zero-length": "Invalid property expression: zero-length",
+        "error-unexpected-space-character": "Invalid property expression: unexpected ' ' at position __index__",
+        "error-empty-key": "Invalid property expression: key is empty",
+        "error-use-undefined-storage": "Undefined storage '__storage__' is specified"
     }
+
 }
diff --git a/red/runtime/nodes/context/index.js b/red/runtime/nodes/context/index.js
index 2a00d40d3..31721e659 100644
--- a/red/runtime/nodes/context/index.js
+++ b/red/runtime/nodes/context/index.js
@@ -16,6 +16,7 @@
 
 var clone = require("clone");
 var util = require("../../util");
+var log = require("../../log");
 
 var settings;
 var contexts = {};
@@ -55,7 +56,7 @@ function load() {
                     try{
                         plugin = require("./"+plugins[pluginName].module);
                     }catch(err){
-                        throw new Error(plugins[pluginName].module + " could not be loaded");
+                        throw new Error(log._("context.error-module-not-loaded", {module:plugins[pluginName].module}));
                     }
                 } else {
                     plugin = plugins[pluginName].module;
@@ -63,14 +64,14 @@ function load() {
                 plugin.init(config);
                 externalContexts[pluginName] = plugin;
             }else{
-                throw new Error("module is not defined in settings.contextStorage." + pluginName );
+                throw new Error(log._("context.error-module-not-defined", {storage:pluginName}));
             }
         }
         if(alias){
             if(externalContexts.hasOwnProperty(alias)){
                 externalContexts["default"] = externalContexts[alias];
             }else{
-                throw new Error("default is invalid. module name=" + plugins["default"])
+                throw new Error(log._("context.error-invalid-default-module", {storage:plugins["default"]}));
             }
         }
     } else {
@@ -86,31 +87,52 @@ function copySettings(config, settings){
     });
 }
 
-function parseKey(key){
-    if(!key){
-        return null;
+function parseStorage(key) {
+    if (!key || key.charAt(0) !== '$') {
+        return "";
+    } else {
+        var endOfStorageName = key.indexOf(".");
+        if (endOfStorageName == -1) {
+            endOfStorageName = key.length;
+        }
+        return key.substring(1,endOfStorageName)||"default";
     }
-    var keyPath = {storage: "", key: ""};
-    var index_$ = key.indexOf("$");
-    var index_dot = key.indexOf(".", 1);
-    if(index_$===0&&index_dot) {
-        keyPath.storage = key.substring(1,index_dot)||"default";
-        keyPath.key = key.substring(index_dot+1);
+}
+
+function parseKey(key) {
+    if (!key) {
+        throw new Error(log._("context.error-key-zero-length"));
+    }
+    var indexSpace = key.indexOf(" ");
+    if (indexSpace != -1) {
+        throw new Error(log._("context.error-unexpected-space-character", {index:indexSpace}));
+    }
+    var keyPath = { storage: "", key: "" };
+    var indexDot = key.indexOf(".");
+    // The key of "$file" should be treated as a key without persistable context.
+    if (indexDot != -1) {
+        keyPath.storage = parseStorage(key);
+    }
+    if (keyPath.storage) {
+        keyPath.key = key.substring(indexDot + 1);
     } else {
         keyPath.key = key;
     }
+    if(!keyPath.key) {
+        throw new Error(log._("context.error-empty-key"));
+    }
     return keyPath;
 }
 
-function getContextStorage(keyPath) {
-    if (noContextStorage || !keyPath.storage) {
+function getContextStorage(storage) {
+    if (noContextStorage || !storage) {
         return externalContexts["_"];
-    } else if (externalContexts.hasOwnProperty(keyPath.storage)) {
-        return externalContexts[keyPath.storage];
+    } else if (externalContexts.hasOwnProperty(storage)) {
+        return externalContexts[storage];
     } else if (externalContexts.hasOwnProperty("default")) {
         return externalContexts["default"];
     } else {
-        var contextError = new Error(keyPath.storage + " is not defined in contextStorage on settings.js");
+        var contextError = new Error(log._("context.error-use-undefined-storage", {storage:storage}));
         contextError.name = "ContextError";
         throw contextError;
     }
@@ -122,21 +144,19 @@ function createContext(id,seed) {
 
     obj.get = function(key) {
         var keyPath = parseKey(key);
-        var context = getContextStorage(keyPath);
+        var context = getContextStorage(keyPath.storage);
         return context.get(keyPath.key, scope);
     };
     obj.set = function(key, value) {
         var keyPath = parseKey(key);
-        var context = getContextStorage(keyPath);
+        var context = getContextStorage(keyPath.storage);
         return context.set(keyPath.key, value, scope);
     };
-    obj.keys = function() {
+    obj.keys = function(storage) {
         //TODO: discuss about keys() behavior
-        var keys = [];
-        for(var plugin in externalContexts){
-            keys.concat(externalContexts[plugin].keys(scope));
-        }
-        return keys;
+        var storageName = parseStorage(storage);
+        var context = getContextStorage(storageName);
+        return context.keys(scope);
     };
     if(id === "global"){
         externalContexts["_"].setGlobalContext(seed);
diff --git a/test/red/runtime/nodes/context/index_spec.js b/test/red/runtime/nodes/context/index_spec.js
index e339de7e1..bc9e6aff6 100644
--- a/test/red/runtime/nodes/context/index_spec.js
+++ b/test/red/runtime/nodes/context/index_spec.js
@@ -163,21 +163,6 @@ describe('context', function() {
                 config:{}
             }
         };
-        var contextDefaultStorage={
-            default: "test",
-            test:{
-                module: {
-                    init: function() {
-                        return true;
-                    },
-                    get: stubGet,
-                    set: stubSet,
-                    keys: stubKeys,
-                    delete: stubDelete
-                },
-                config:{}
-            }
-        };
 
         afterEach(function(done) {
             stubGet.reset();
@@ -193,7 +178,68 @@ describe('context', function() {
             context =  Context.get("1","flow");
         }
 
+        describe('key name',function() {
+            var memoryStorage = {
+                memory: {
+                    module: "memory"
+                }
+            };
+            beforeEach(function() {
+                Context.init({contextStorage:memoryStorage});
+                Context.load();
+                context =  Context.get("1","flow");
+            });
+            afterEach(function() {
+                Context.clean({allNodes:{}});
+            });
+            it('should work correctly with the valid key name',function() {
+                context.set("$memory.azAZ09$_","valid");
+                context.get("$memory.azAZ09$_").should.eql("valid");
+                context.set("$memory.a.b","ab");
+                context.get("$memory.a.b").should.eql("ab");
+            });
+            it('should treat the key name without dot as a normal context',function() {
+                context.set("$memory","normal");
+                context.get("$memory").should.eql("normal");
+            });
+            it('should fail when specifying invalid characters',function() {
+                (function() {
+                    context.set("$memory.a.-","invalid1");
+                }).should.throw();
+                (function() {
+                    context.set("$memory.'abc","invalid2");
+                }).should.throw();
+            });
+            it('should fail when specifying unnecesary space characters for key name',function() {
+                (function() {
+                    context.set("$ memory.space","space1");
+                }).should.throw();
+                (function() {
+                    context.set("$memory .space","space2");
+                }).should.throw();
+                (function() {
+                    context.set("$memory. space","space3");
+                }).should.throw();
+            });
+        });
+
         describe('if external context storage exists',function() {
+            var contextDefaultStorage={
+                default: "test",
+                test:{
+                    module: {
+                        init: function() {
+                            return true;
+                        },
+                        get: stubGet,
+                        set: stubSet,
+                        keys: stubKeys,
+                        delete: stubDelete
+                    },
+                    config:{}
+                }
+            };
+
             it('should store local property to external context storage',function() {
                 initializeContext();
                 should.not.exist(context.get("$test.foo"));
@@ -224,7 +270,7 @@ describe('context', function() {
                 stubSet.called.should.be.true();
                 stubKeys.called.should.be.true();
             });
-            it('should store data on default context', function() {
+            it('should store data when non-existent context storage was specified', function() {
                 Context.init({contextStorage:contextDefaultStorage});
                 Context.load();
                 context =  Context.get("1","flow");
@@ -236,12 +282,39 @@ describe('context', function() {
                 stubSet.called.should.be.true();
                 stubKeys.called.should.be.true();
             });
+            it('should use the default context', function() {
+                Context.init({contextStorage:contextDefaultStorage});
+                Context.load();
+                context =  Context.get("1","flow");
+                should.not.exist(context.get("$default.foo"));
+                context.set("$default.foo","default");
+                context.get("$default.foo");
+                context.keys("$default");
+                stubGet.called.should.be.true();
+                stubSet.called.should.be.true();
+                stubKeys.called.should.be.true();
+            });
+            it('should use the alias of default context', function() {
+                Context.init({contextStorage:contextDefaultStorage});
+                Context.load();
+                context =  Context.get("1","flow");
+                should.not.exist(context.get("$.foo"));
+                context.set("$.foo","alias");
+                context.get("$.foo");
+                context.keys("$");
+                stubGet.called.should.be.true();
+                stubSet.called.should.be.true();
+                stubKeys.called.should.be.true();
+            });
             it('should load memory module', function(done) {
                 Context.init({ contextStorage: { _: {}}});
                 try {
                     Context.load();
-                    context.set("_.foo","test");
-                    context.get("$_.foo");
+                    context.set("$_.foo","mem1");
+                    context.get("$_.foo").should.eql("mem1");
+                    var keys = context.keys("$_");
+                    keys.should.have.length(1);
+                    keys[0].should.eql("foo");
                     done();
                 } catch (err) {
                     done(err);
@@ -256,6 +329,27 @@ describe('context', function() {
                     done(err);
                 }
             });
+            it('should accept special storage name', function(done) {
+                Context.init({
+                    contextStorage:{
+                        "#%&":{module:"memory"},
+                        \u3042:{module:"memory"},
+                        1:{module:"localfilesystem"},
+                    }
+                });
+                try {
+                    Context.load();
+                    context.set("$#%&.sign","sign1");
+                    context.get("$#%&.sign").should.eql("sign1");
+                    context.set("$\u3042.file2","file2");
+                    context.get("$\u3042.file2").should.eql("file2");
+                    context.set("$1.num","num3");
+                    context.get("$1.num").should.eql("num3");
+                    done();
+                } catch (err) {
+                    done(err);
+                }
+            });
         });
 
         describe('if external context storage does not exist',function() {
@@ -285,18 +379,11 @@ describe('context', function() {
                     }
                 }
             });
-            it('should fail when using invalid default context', function(done) {
+            it('should fail when using invalid default context', function() {
                 Context.init({contextStorage:{default:"noexist"}});
-                try {
+                (function() {
                     Context.load();
-                    try {
-                        should.fail(null, null, "An error was not thrown using undefined storage for flow context");
-                    } catch (err) {
-                        done(err);
-                    }
-                } catch (err) {
-                    done();
-                }
+                }).should.throw();
             });
             it('should store data on memory when contextStorage is not defined', function() {
                 Context.init({});
@@ -309,31 +396,17 @@ describe('context', function() {
                 context.global.set("$nonexist.key1", "val3");
                 context.global.get("$nonexist.key1").should.eql("val3");
             });
-            it('should fail for the storage with no module', function(done) {
+            it('should fail for the storage with no module', function() {
                 Context.init({ contextStorage: { test: {}}});
-                try {
+                (function() {
                     Context.load();
-                    try {
-                        should.fail(null, null, "Should fail when no module was specified");
-                    } catch (err) {
-                        done(err);
-                    }
-                } catch (err) {
-                    done();
-                }
+                }).should.throw();
             });
-            it('should fail to load non-existent module', function(done) {
+            it('should fail to load non-existent module', function() {
                 Context.init({contextStorage:{ file:{module:"nonexistent"} }});
-                try {
+                (function() {
                     Context.load();
-                    try {
-                        should.fail(null, null, "Should fail to load non-existent module");
-                    } catch (err) {
-                        done(err);
-                    }
-                } catch (err) {
-                    done();
-                }
+                }).should.throw();
             });
         });
     });
@@ -347,12 +420,6 @@ describe('context', function() {
             result.key.should.eql(expectedKey);
         };
 
-        function returnModule(input, expectedModule) {
-            var result = parseKey(input);
-            result.storage.should.eql(expectedModule);
-            should(result.key).be.null();
-        };
-
         it('should return module and key', function() {
             returnModuleAndKey("$test.aaa","test","aaa");
             returnModuleAndKey("$test.aaa.bbb","test","aaa.bbb");
@@ -362,32 +429,48 @@ describe('context', function() {
             returnModuleAndKey("$test.$foo.$bar","test","$foo.$bar"); 
             returnModuleAndKey("$test..foo","test",".foo");
             returnModuleAndKey("$test..","test",".");
+            returnModuleAndKey("$te-_st.aaa","te-_st","aaa");
+            returnModuleAndKey("$te{st.a2","te{st","a2");
+            returnModuleAndKey("$te[st.a3","te[st","a3");
+            returnModuleAndKey("$te'st.a4","te'st","a4");
+            returnModuleAndKey("$te\"st.a5","te\"st","a5");
         });
 
-        // it('should return only module', function() {
-        //     returnModule("$test","test",null);
-        //     returnModule("$1","1",null);
-        //     returnModule("$$test","$test",null);
-        //     returnModule("$test.","test.",null);
-        // });
-
         it('should return module as default', function() {
             returnModuleAndKey("$default.foo","default","foo");
             returnModuleAndKey("$.foo","default","foo");
-            // returnModule("$default","default");
-            // returnModule("$","default");
         });
 
-        it('should return null', function() {
-            var keyPath = parseKey("test.aaa");
-            keyPath.storage.should.eql("");
-            keyPath.key.should.eql("test.aaa");
+        it('should return only keys', function() {
+            returnModuleAndKey("test.aaa", "", "test.aaa");
+            returnModuleAndKey("test", "", "test");
+            returnModuleAndKey("$test", "", "$test");
+        });
 
-            keyPath = parseKey("test");
-            keyPath.storage.should.eql("");
-            keyPath.key.should.eql("test");
+        it('should fail with null key', function() {
+            (function() {
+                parseKey("");
+            }).should.throw();
 
-            should(parseKey(null)).be.null();
+            (function() {
+                parseKey(null);
+            }).should.throw();
+        });
+
+        it('should fail with space character', function() {
+            (function() {
+                parseKey(" $test");
+            }).should.throw();
+
+            (function() {
+                parseKey("$test .a");
+            }).should.throw();
+        });
+
+        it('should fail with empty key', function() {
+            (function() {
+                parseKey("$test.");
+            }).should.throw();
         });
     });