diff --git a/storage/externalStorage.go b/storage/externalStorage.go
new file mode 100644
index 0000000000000000000000000000000000000000..3f41d0bc7f8b764dfe4c712e80aa48a663ffd725
--- /dev/null
+++ b/storage/externalStorage.go
@@ -0,0 +1,405 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright © 2022 xx foundation                                             //
+//                                                                            //
+// Use of this source code is governed by a license that can be found in the  //
+// LICENSE file.                                                              //
+////////////////////////////////////////////////////////////////////////////////
+
+//go:build js && wasm
+
+package storage
+
+import (
+	"errors"
+	"os"
+	"strings"
+	"syscall/js"
+
+	"github.com/Max-Sum/base32768"
+
+	"gitlab.com/elixxir/wasm-utils/exception"
+	"gitlab.com/elixxir/wasm-utils/utils"
+)
+
+// externalStorageWasmPrefix is prefixed to every keyName saved to external storage by
+// externalStorage. It allows the identification and deletion of keys only created
+// by this WASM binary while ignoring keys made by other scripts on the same
+// page.
+//
+// The chosen prefix is two characters, that when converted to UTF16, take up 4
+// bytes without any zeros to make them more unique.
+const externalStorageWasmPrefix = "🞮🞮"
+
+var UnimplementedErr = errors.New("not implemented")
+
+// ExternalStorage defines an interface for setting persistent state in a KV format
+// specifically for web-based implementations.
+type ExternalStorage interface {
+	// Get decodes and returns the value from the external storage given its key
+	// name. Returns os.ErrNotExist if the key does not exist.
+	Get(key string) ([]byte, error)
+
+	// Set encodes the bytes to a string and adds them to external storage at the
+	// given key name. Returns an error if external storage quota has been reached.
+	Set(key string, value []byte) error
+
+	// Delete removes a key's value from external storage given its name. If
+	// there is no item with the given key, this function does nothing.
+	Delete(keyName string) error
+
+	// Clear clears all the keys in storage. Returns the number of keys cleared and any error.
+	Clear() (int, error)
+
+	// ClearPrefix clears all keys with the given prefix. Returns the number of
+	// keys cleared and any error.
+	ClearPrefix(prefix string) (int, error)
+
+	// Key returns the name of the nth key in externalStorage. Returns
+	// os.ErrNotExist if the key does not exist. The order of keys is not
+	// defined.
+	Key(n int) (string, error)
+
+	// Keys returns a list of all key names in external storage.
+	Keys() ([]string, error)
+
+	// GetPrefix returns the full Prefix of the KV
+	GetPrefix() string
+
+	// HasPrefix returns whether this prefix exists in the KV
+	HasPrefix(prefix string) bool
+
+	// Prefix returns a new KV with the new prefix appending
+	Prefix(prefix string) (ExternalStorage, error)
+
+	// Root returns the KV with no prefixes
+	Root() ExternalStorage
+
+	// IsMemStore returns true if the underlying KV is memory based
+	IsMemStore() (bool, error)
+
+	// Length returns the number of keys in localStorage.
+	Length() int
+
+	// ExternalStorageUNSAFE returns the underlying external storage wrapper. This can
+	// be UNSAFE and should only be used if you know what you are doing.
+	//
+	// The returned wrapper wraps all the functions and fields on the Javascript
+	// havenStorage object to handle type conversions and errors. But it does
+	// not decode/sanitize the inputs/outputs or track entries using the prefix
+	// system. If using it, make sure all key names and values can be converted
+	// to valid UCS-2 strings.
+	ExternalStorageUNSAFE() *HavenStorageJS
+}
+
+// externalStorage contains the js.Value representation of havenStorage.
+type externalStorage struct {
+	// The Javascript value containing the havenStorage object
+	v *HavenStorageJS
+
+	// The prefix appended to each key name. This is so that all keys created by
+	// this structure can be deleted without affecting other keys in external
+	// storage.
+	prefix string
+}
+
+// jsStorage is the global that stores Javascript as window.havenStorage.
+var jsExternalStorage ExternalStorage = newExternalStorage(externalStorageWasmPrefix)
+
+// checkUnimplementedErr checks if the error is UnimplementedErr, if yes return
+// UnimplementedErr otherwise return the error
+func checkUnimplementedErr(jsErr []js.Value) error {
+	// todo it can be of non error type
+	jsError := js.Error{Value: jsErr[0]}
+	if jsError.Error() == "JavaScript error: not implemented" {
+		return UnimplementedErr
+	}
+	return jsError
+}
+
+// newExternalStorage creates a new externalStorage object with the specified prefix.
+func newExternalStorage(prefix string) *externalStorage {
+	return &externalStorage{
+		v:      &HavenStorageJS{js.Global().Get("havenStorage")},
+		prefix: prefix,
+	}
+}
+
+// GetExternalStorage returns Javascript's external storage.
+func GetExternalStorage() ExternalStorage {
+	return jsExternalStorage
+}
+
+// Get decodes and returns the value from the external storage given its key
+// name. Returns os.ErrNotExist if the key does not exist.
+func (ls *externalStorage) Get(keyName string) ([]byte, error) {
+	value, err := ls.v.GetItem(ls.prefix + keyName)
+	if err != nil {
+		return nil, err
+	}
+
+	return base32768.SafeEncoding.DecodeString(value)
+}
+
+// Set encodes the bytes to a string and adds them to external storage at the
+// given key name. Returns an error if external storage quota has been reached.
+func (ls *externalStorage) Set(keyName string, keyValue []byte) error {
+	encoded := base32768.SafeEncoding.EncodeToString(keyValue)
+	return ls.v.SetItem(ls.prefix+keyName, encoded)
+}
+
+// RemoveItem removes a key's value from external storage given its name. If there
+// is no item with the given key, this function does nothing.
+func (ls *externalStorage) Delete(keyName string) error {
+	return ls.v.Delete(ls.prefix + keyName)
+}
+
+// Clear clears all the keys in storage. Returns the number of keys cleared and any error.
+func (ls *externalStorage) Clear() (int, error) {
+	// Get a copy of all key names at once
+	keys, err := ls.v.KeysPrefix(ls.prefix)
+	if err != nil {
+		return 0, err
+	}
+
+	// Loop through each key
+	for _, keyName := range keys {
+		if err := ls.Delete(keyName); err != nil {
+			return 0, err
+		}
+	}
+
+	return len(keys), nil
+}
+
+// ClearPrefix clears all keys with the given prefix. Returns the number of
+// keys cleared and any error.
+func (ls *externalStorage) ClearPrefix(prefix string) (int, error) {
+	// Get a copy of all key names at once
+	keys, err := ls.v.KeysPrefix(ls.prefix + prefix)
+	if err != nil {
+		return 0, err
+	}
+
+	// Loop through each key
+	for _, keyName := range keys {
+		if err := ls.Delete(prefix + keyName); err != nil {
+			return 0, err
+		}
+	}
+
+	return len(keys), nil
+}
+
+// Key returns the name of the nth key in externalStorage. Return [os.ErrNotExist]
+// if the key does not exist. The order of keys is not defined.
+func (ls *externalStorage) Key(n int) (string, error) {
+	keyName, err := ls.v.Key(n)
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimPrefix(keyName, ls.prefix), nil
+}
+
+// Keys returns a list of all key names in external storage.
+func (ls *externalStorage) Keys() ([]string, error) {
+	keys, err := ls.v.KeysPrefix(ls.prefix)
+	if err != nil {
+		return nil, err
+	}
+	return keys, nil
+}
+
+func (ls *externalStorage) GetPrefix() string {
+	return ls.prefix
+}
+
+func (ls *externalStorage) HasPrefix(prefix string) bool {
+	return strings.HasPrefix(ls.prefix, prefix)
+}
+
+func (ls *externalStorage) Prefix(prefix string) (ExternalStorage, error) {
+	return newExternalStorage(ls.prefix + prefix), nil
+}
+
+func (ls *externalStorage) Root() ExternalStorage {
+	return newExternalStorage("")
+}
+
+func (ls *externalStorage) IsMemStore() (bool, error) {
+	return ls.v.IsMemStore()
+}
+
+func (ls *externalStorage) Length() int {
+	return ls.v.Length()
+}
+
+// ExternalStorageUNSAFE returns the underlying external storage wrapper. This can be
+// UNSAFE and should only be used if you know what you are doing.
+//
+// The returned wrapper wraps all the functions and fields on the Javascript
+// havenStorage object to handle type conversions and errors. But it does not
+// decode/sanitize the inputs/outputs or track entries using the prefix system.
+// If using it, make sure all key names and values can be converted to valid
+// UCS-2 strings.
+func (ls *externalStorage) ExternalStorageUNSAFE() *HavenStorageJS {
+	return ls.v
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Javascript Wrappers                                                        //
+////////////////////////////////////////////////////////////////////////////////
+
+// StorageOperation defines the supported operations for HavenStorageJS
+type StorageOperation string
+
+const (
+	// GetItemOp represents the "getItem" operation
+	GetItemOp StorageOperation = "getItem"
+	// SetItemOp represents the "setItem" operation
+	SetItemOp StorageOperation = "setItem"
+	// DeleteOp represents the "delete" operation
+	DeleteOp StorageOperation = "delete"
+	// ClearOp represents the "clear" operation
+	ClearOp StorageOperation = "clear"
+	// KeysOp represents the "getKeys" operation
+	KeysOp StorageOperation = "getKeys"
+
+	// IsMemStoreOp represents the "isMemStore" operation
+	IsMemStoreOp StorageOperation = "isMemStore"
+)
+
+// HavenStorageJS stores the Javascript window.havenStorage object and wraps all
+// of its methods and fields to handle type conversations and errors.
+type HavenStorageJS struct {
+	js.Value
+}
+
+// callStorage is a helper function that calls the specified operation on the storage object
+// with the provided arguments and returns the result.
+func (ls *HavenStorageJS) callStorage(op StorageOperation, args ...interface{}) js.Value {
+	return ls.Call(string(op), args...)
+}
+
+// GetItem returns the value from the external storage given its key name. Returns
+// [os.ErrNotExist] if the key does not exist.
+//
+// Doc: https://developer.mozilla.org/en-US/docs/Web/API/Storage/getItem
+func (ls *HavenStorageJS) GetItem(keyName string) (keyValue string, err error) {
+	defer exception.Catch(&err)
+	promise := ls.callStorage(GetItemOp, keyName)
+	result, jsErr := utils.Await(promise)
+	if jsErr != nil {
+		return "", checkUnimplementedErr(jsErr)
+	}
+	if result[0].IsNull() {
+		return "", os.ErrNotExist
+	}
+	return result[0].String(), nil
+}
+
+// SetItem adds the value to external storage at the given key name. Returns an
+// error if external storage quota has been reached.
+//
+// Doc: https://developer.mozilla.org/en-US/docs/Web/API/Storage/setItem
+func (ls *HavenStorageJS) SetItem(keyName, keyValue string) (err error) {
+	defer exception.Catch(&err)
+	promise := ls.callStorage(SetItemOp, keyName, keyValue)
+	_, jsErr := utils.Await(promise)
+	if jsErr != nil {
+		return checkUnimplementedErr(jsErr)
+	}
+	return nil
+}
+
+// RemoveItem removes a key's value from external storage given its name. If there
+// is no item with the given key, this function does nothing.
+//
+// Doc: https://developer.mozilla.org/en-US/docs/Web/API/Storage/removeItem
+func (ls *HavenStorageJS) Delete(keyName string) error {
+	promise := ls.callStorage(DeleteOp, keyName)
+	_, jsErr := utils.Await(promise)
+	if jsErr != nil {
+		return checkUnimplementedErr(jsErr)
+	}
+	return nil
+}
+
+// Clear clears all the keys in storage.
+//
+// Doc: https://developer.mozilla.org/en-US/docs/Web/API/Storage/clear
+func (ls *HavenStorageJS) Clear() error {
+	promise := ls.callStorage(ClearOp)
+	_, jsErr := utils.Await(promise)
+	if jsErr != nil {
+		return checkUnimplementedErr(jsErr)
+	}
+	return nil
+}
+
+// Key returns the name of the nth key in externalStorage. Return [os.ErrNotExist]
+// if the key does not exist. The order of keys is not defined.
+//
+// Doc: https://developer.mozilla.org/en-US/docs/Web/API/Storage/key
+func (ls *HavenStorageJS) Key(n int) (keyName string, err error) {
+	defer exception.Catch(&err)
+	promise := ls.Call("key", n)
+	result, jsErr := utils.Await(promise)
+	if jsErr != nil {
+		return "", checkUnimplementedErr(jsErr)
+	}
+	if result[0].IsNull() {
+		return "", os.ErrNotExist
+	}
+	return result[0].String(), nil
+}
+
+// Keys returns a list of all key names in external storage.
+func (ls *HavenStorageJS) Keys() ([]string, error) {
+	promise := ls.callStorage(KeysOp)
+	result, jsErr := utils.Await(promise)
+	if jsErr != nil {
+		return []string{}, checkUnimplementedErr(jsErr)
+	}
+
+	keysJS := result[0]
+	keys := make([]string, keysJS.Length())
+	for i := range keys {
+		keys[i] = keysJS.Index(i).String()
+	}
+	return keys, nil
+}
+
+// KeysPrefix returns a list of all key names in external storage with the given
+// prefix and trims the prefix from each key name.
+func (ls *HavenStorageJS) KeysPrefix(prefix string) ([]string, error) {
+	promise := ls.callStorage(KeysOp)
+	result, jsErr := utils.Await(promise)
+	if jsErr != nil {
+		return []string{}, checkUnimplementedErr(jsErr)
+	}
+
+	keysJS := result[0]
+	keys := make([]string, 0, keysJS.Length())
+	for i := 0; i < keysJS.Length(); i++ {
+		keyName := keysJS.Index(i).String()
+		if strings.HasPrefix(keyName, prefix) {
+			keys = append(keys, strings.TrimPrefix(keyName, prefix))
+		}
+	}
+	return keys, nil
+}
+
+func (ls *HavenStorageJS) IsMemStore() (bool, error) {
+	result := ls.callStorage(IsMemStoreOp)
+	var err error
+	defer exception.Catch(&err)
+	if err != nil {
+		//TODO
+		jsErr, ok := err.(js.Error)
+		if ok {
+			return false, checkUnimplementedErr([]js.Value{js.ValueOf(jsErr)})
+		}
+		return false, err
+	}
+	return result.Bool(), nil
+}
diff --git a/storage/externalStorage_test.go b/storage/externalStorage_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..418d2e0f632ba84fa13bdcd92b81c8a66003d315
--- /dev/null
+++ b/storage/externalStorage_test.go
@@ -0,0 +1,379 @@
+////////////////////////////////////////////////////////////////////////////////
+// Copyright © 2022 xx foundation                                             //
+//                                                                            //
+// Use of this source code is governed by a license that can be found in the  //
+// LICENSE file.                                                              //
+////////////////////////////////////////////////////////////////////////////////
+
+//go:build js && wasm
+
+package storage
+
+import (
+	"bytes"
+	"os"
+	"reflect"
+	"strconv"
+	"syscall/js"
+	"testing"
+
+	"github.com/pkg/errors"
+)
+
+// setupMockHavenStorage sets up a mock implementation of havenStorage in the JavaScript environment
+func setupMockHavenStorage(_ *testing.T) {
+	const setupScript = `
+	const havenStorage = {
+		getItem: function(key) {
+			return Promise.resolve(localStorage.getItem(key));
+		},
+
+		setItem: function(key, value) {
+			localStorage.setItem(key, value);
+			return Promise.resolve();
+		},
+
+		delete: function(key) {
+			localStorage.removeItem(key);
+			return Promise.resolve();
+		},
+
+		clear: function() {
+			localStorage.clear();
+			return Promise.resolve();
+		},
+
+		getKeys: function() {
+			return Promise.resolve(Object.keys(localStorage));
+		},
+
+		key: function(index) {
+			// To Test unimplemented error
+			return Promise.reject(new Error('not implemented'));
+		},
+
+		isMemStore: function() {
+			return Promise.resolve(false);
+		},
+
+		length: function() {
+			return Promise.resolve(0);
+		},
+	};
+
+	// Initialize mock storage
+	window._mockHavenStorage = {};
+	window.havenStorage = havenStorage;
+	`
+	js.Global().Call("eval", setupScript)
+	jsExternalStorage = newExternalStorage(externalStorageWasmPrefix)
+}
+
+func TestExternalStorage_GetPrefix(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	es := GetExternalStorage()
+
+	prefix := es.GetPrefix()
+	if prefix != externalStorageWasmPrefix {
+		t.Errorf("Expected prefix to be %q, got %q", externalStorageWasmPrefix, prefix)
+	}
+}
+
+func TestExternalStorage_HasPrefix(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	es := GetExternalStorage()
+
+	hasPrefix := es.HasPrefix(externalStorageWasmPrefix)
+	if !hasPrefix {
+		t.Errorf("Expected hasPrefix to be true")
+	}
+
+	hasPrefix = es.HasPrefix("someOtherPrefix")
+	if hasPrefix {
+		t.Errorf("Expected hasPrefix to be false")
+	}
+}
+
+func TestExternalStorage_Prefix(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	es := GetExternalStorage()
+
+	prefix, err := es.Prefix("testPrefix")
+	if err != nil {
+		t.Errorf("Failed to get prefix: %+v", err)
+	}
+
+	if prefix.GetPrefix() != externalStorageWasmPrefix+"testPrefix" {
+		t.Errorf("Expected prefix to be %q, got %q", externalStorageWasmPrefix+"testPrefix", prefix.GetPrefix())
+	}
+}
+
+func TestExternalStorage_Root(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	es := GetExternalStorage()
+
+	root := es.Root()
+	if root.GetPrefix() != "" {
+		t.Errorf("Expected prefix to be %q, got %q", "", root.GetPrefix())
+	}
+}
+
+func TestExternalStorage_IsMemStore(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	es := GetExternalStorage()
+
+	isMemStore, err := es.IsMemStore()
+	if err != nil {
+		t.Errorf("Failed to get isMemStore: %+v", err)
+	}
+
+	if isMemStore {
+		t.Errorf("Expected memstore to be false")
+	}
+}
+
+func TestExternalStorage_Length(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	es := GetExternalStorage()
+
+	length := es.Length()
+	if length != 0 {
+		t.Errorf("Expected length to be %d, got %d", 0, length)
+	}
+}
+
+// Unit test of GetExternalStorage.
+func TestGetExternalStorage(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	expected := &externalStorage{
+		v:      &HavenStorageJS{js.Global().Get("havenStorage")},
+		prefix: externalStorageWasmPrefix,
+	}
+
+	es := GetExternalStorage()
+
+	if !reflect.DeepEqual(expected, es) {
+		t.Errorf("Did not receive expected externalStorage."+
+			"\nexpected: %+v\nreceived: %+v", expected, es)
+	}
+}
+
+// Tests that a value set with externalStorage.Set and retrieved with
+// externalStorage.Get matches the original.
+func TestExternalStorage_Get_Set(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	values := map[string][]byte{
+		"key1": []byte("key value"),
+		"key2": {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
+		"key3": {0, 49, 0, 0, 0, 38, 249, 93, 242, 189, 222, 32, 138, 248, 121,
+			151, 42, 108, 82, 199, 163, 61, 4, 200, 140, 231, 225, 20, 35, 243,
+			253, 161, 61, 2, 227, 208, 173, 183, 33, 66, 236, 107, 105, 119, 26,
+			42, 44, 60, 109, 172, 38, 47, 220, 17, 129, 4, 234, 241, 141, 81,
+			84, 185, 32, 120, 115, 151, 128, 196, 143, 117, 222, 78, 44, 115,
+			109, 20, 249, 46, 158, 139, 231, 157, 54, 219, 141, 252},
+	}
+
+	for keyName, keyValue := range values {
+		err := jsExternalStorage.Set(keyName, keyValue)
+		if err != nil {
+			t.Errorf("Failed to set %q: %+v", keyName, err)
+		}
+
+		loadedValue, err := jsExternalStorage.Get(keyName)
+		if err != nil {
+			t.Errorf("Failed to load %q: %+v", keyName, err)
+		} else if !bytes.Equal(keyValue, loadedValue) {
+			t.Errorf("Loaded value does not match original for %q"+
+				"\nexpected: %q\nreceived: %q", keyName, keyValue, loadedValue)
+		}
+	}
+}
+
+// Tests that externalStorage.Delete deletes a key from the store and that it
+// cannot be retrieved.
+func TestExternalStorage_Delete(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	keyName := "key"
+	if err := jsExternalStorage.Set(keyName, []byte("value")); err != nil {
+		t.Errorf("Failed to set %q: %+v", keyName, err)
+	}
+
+	err := jsExternalStorage.Delete(keyName)
+	if err != nil {
+		t.Errorf("Failed to delete key %q: %+v", keyName, err)
+	}
+
+	_, err = jsExternalStorage.Get(keyName)
+	if err == nil || !errors.Is(err, os.ErrNotExist) {
+		t.Errorf("Failed to remove %q: %+v", keyName, err)
+	}
+}
+
+// Tests that externalStorage.Clear deletes all the WASM keys from storage and
+// does not remove any others
+func TestExternalStorage_Clear(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	// Clear any existing data
+	jsExternalStorage.ExternalStorageUNSAFE().Clear()
+
+	const numKeys = 10
+	var yesPrefix, noPrefix []string
+
+	for i := 0; i < numKeys; i++ {
+		keyName := "keyNum" + strconv.Itoa(i)
+		if i%2 == 0 {
+			yesPrefix = append(yesPrefix, keyName)
+			err := jsExternalStorage.Set(keyName, []byte(strconv.Itoa(i)))
+			if err != nil {
+				t.Errorf("Failed to set with prefix %q: %+v", keyName, err)
+			}
+		} else {
+			noPrefix = append(noPrefix, keyName)
+			err := jsExternalStorage.ExternalStorageUNSAFE().SetItem(keyName, strconv.Itoa(i))
+			if err != nil {
+				t.Errorf("Failed to set with no prefix %q: %+v", keyName, err)
+			}
+		}
+	}
+
+	n, err := jsExternalStorage.Clear()
+	if err != nil {
+		t.Errorf("Failed to clear storage: %+v", err)
+	}
+	if n != numKeys/2 {
+		t.Errorf("Incorrect number of keys.\nexpected: %d\nreceived: %d",
+			numKeys/2, n)
+	}
+
+	for _, keyName := range noPrefix {
+		if _, err := jsExternalStorage.ExternalStorageUNSAFE().GetItem(keyName); err != nil {
+			t.Errorf("Could not get keyName %q: %+v", keyName, err)
+		}
+	}
+	for _, keyName := range yesPrefix {
+		keyValue, err := jsExternalStorage.Get(keyName)
+		if err == nil || !errors.Is(err, os.ErrNotExist) {
+			t.Errorf("Found keyName %q: %q", keyName, keyValue)
+		}
+	}
+}
+
+// Tests that externalStorage.ClearPrefix deletes only the keys with the given
+// prefix.
+func TestExternalStorage_ClearPrefix(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	// Clear any existing data
+	jsExternalStorage.ExternalStorageUNSAFE().Clear()
+
+	const numKeys = 10
+	var yesPrefix, noPrefix []string
+	prefix := "keyNamePrefix/"
+
+	for i := 0; i < numKeys; i++ {
+		keyName := "keyNum " + strconv.Itoa(i)
+		if i%2 == 0 {
+			keyName = prefix + keyName
+			yesPrefix = append(yesPrefix, keyName)
+		} else {
+			noPrefix = append(noPrefix, keyName)
+		}
+
+		if err := jsExternalStorage.Set(keyName, []byte(strconv.Itoa(i))); err != nil {
+			t.Errorf("Failed to set %q: %+v", keyName, err)
+		}
+	}
+
+	n, err := jsExternalStorage.ClearPrefix(prefix)
+	if err != nil {
+		t.Errorf("Failed to clear prefix: %+v", err)
+	}
+	if n != numKeys/2 {
+		t.Errorf("Incorrect number of keys.\nexpected: %d\nreceived: %d",
+			numKeys/2, n)
+	}
+
+	for _, keyName := range noPrefix {
+		if _, err := jsExternalStorage.Get(keyName); err != nil {
+			t.Errorf("Could not get keyName %q: %+v", keyName, err)
+		}
+	}
+	for _, keyName := range yesPrefix {
+		keyValue, err := jsExternalStorage.Get(keyName)
+		if err == nil || !errors.Is(err, os.ErrNotExist) {
+			t.Errorf("Found keyName %q: %q", keyName, keyValue)
+		}
+	}
+}
+
+// Tests that externalStorage.Key return all added keys when looping through all
+// indexes.
+func TestExternalStorage_Key(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	// This test will verify that the UnimplementedErr is properly returned
+	// since the mock implementation rejects the key method
+	_, err := jsExternalStorage.Key(0)
+	if err == nil || !errors.Is(err, UnimplementedErr) {
+		t.Errorf("Expected UnimplementedErr for Key method.\nexpected: %v\nreceived: %v",
+			UnimplementedErr, err)
+	}
+}
+
+// Tests that externalStorage.Get returns the error os.ErrNotExist when the key
+// does not exist in storage.
+func TestExternalStorage_Get_NotExistError(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	_, err := jsExternalStorage.Get("someKey")
+	if err == nil || !errors.Is(err, os.ErrNotExist) {
+		t.Errorf("Incorrect error for non existant key."+
+			"\nexpected: %v\nreceived: %v", os.ErrNotExist, err)
+	}
+}
+
+// Tests that externalStorage.Keys return a list that contains all the added keys.
+func TestExternalStorage_Keys(t *testing.T) {
+	setupMockHavenStorage(t)
+
+	// Clear any existing data
+	jsExternalStorage.ExternalStorageUNSAFE().Clear()
+
+	values := map[string][]byte{
+		"key1": []byte("key value"),
+		"key2": {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
+		"key3": {0, 49, 0, 0, 0, 38, 249, 93},
+	}
+
+	for keyName, keyValue := range values {
+		if err := jsExternalStorage.Set(keyName, keyValue); err != nil {
+			t.Errorf("Failed to set %q: %+v", keyName, err)
+		}
+	}
+
+	keys, err := jsExternalStorage.Keys()
+	if err != nil {
+		t.Errorf("Failed to get keys: %+v", err)
+	}
+
+	if len(keys) != len(values) {
+		t.Errorf("Incorrect number of keys.\nexpected: %d\nreceived: %d",
+			len(values), len(keys))
+	}
+
+	for i, keyName := range keys {
+		if _, exists := values[keyName]; !exists {
+			t.Errorf("Key %q does not exist (%d).", keyName, i)
+		}
+	}
+}