diff --git a/README.md b/README.md
index 5628e55..cd03179 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ The project also includes a watchOS companion app target for watch-specific demo
 1. Open `SecureStorgageSample.xcodeproj`
 2. Select an iOS simulator or device
 3. Build and run (⌘R)
-4. To use App Group demos, set your App Group identifier in `SecureStorgageSample/SecureStorgageSample/Models/AppGroupConfiguration.swift` and enable the entitlement for each target that should share data.
+4. To use App Group demos, enable the App Group entitlement for each target that should share data. The identifier is derived from the bundle ID via SharedKit constants.
 
 ## Project Structure
 
@@ -37,7 +37,8 @@ SharedPackage/
 └── Sources/
     └── SharedKit/
         ├── Constants/
-        │   └── StorageKeyNames.swift
+        │   ├── StorageKeyNames.swift
+        │   └── StorageServiceIdentifiers.swift
         └── Models/
             └── UserProfile.swift
 SecureStorgageSample/
@@ -117,6 +118,7 @@ The app demonstrates various storage configurations:
 
 - Storage keys are now split into one file per key and grouped by domain; platform-focused keys live in `StorageKeys/Platform` with comments calling out availability/sync focus.
 - The shared model/constants live in `SharedPackage` (`SharedKit`) to keep the watch/iOS data contract centralized.
+- Keychain service IDs and App Group identifiers are centralized in `SharedKit/Constants/StorageServiceIdentifiers.swift` to avoid hardcoded strings in keys.
 - The watch app uses a handler-based WatchConnectivity layer so new payload types can be added in `Services/Handlers` without bloating the main service.
 - A `StorageKeyCatalog` sample is included to generate a security audit report of all storage keys.
 - Each `StorageKey` includes a `description` used in audit reports.
diff --git a/SecureStorgageSample/Models/AppGroupConfiguration.swift b/SecureStorgageSample/Models/AppGroupConfiguration.swift
deleted file mode 100644
index 4ec4ad5..0000000
--- a/SecureStorgageSample/Models/AppGroupConfiguration.swift
+++ /dev/null
@@ -1,8 +0,0 @@
-import Foundation
-import SharedKit
-
-enum AppGroupConfiguration {
-    static var identifier: String {
-        StorageServiceIdentifiers.appGroupIdentifier
-    }
-}
diff --git a/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserDefaultsKey.swift b/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserDefaultsKey.swift
index de15c57..93e0a13 100644
--- a/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserDefaultsKey.swift
+++ b/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserDefaultsKey.swift
@@ -1,6 +1,6 @@
 import Foundation
 import LocalData
-
+import SharedKit
 extension StorageKeys {
     /// Stores a shared setting in App Group UserDefaults.
     /// - Domain: App Group UserDefaults
@@ -10,7 +10,7 @@ extension StorageKeys {
         typealias Value = String
 
         let name = "app_group_setting"
-        let domain: StorageDomain = .appGroupUserDefaults(identifier: AppGroupConfiguration.identifier)
+        let domain: StorageDomain = .appGroupUserDefaults(identifier: StorageServiceIdentifiers.appGroupIdentifier)
         let security: SecurityPolicy = .none
         let serializer: Serializer<String> = .json
         let owner = "SampleApp"
diff --git a/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserProfileKey.swift b/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserProfileKey.swift
index 8ade156..ebca327 100644
--- a/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserProfileKey.swift
+++ b/SecureStorgageSample/StorageKeys/AppGroup/AppGroupUserProfileKey.swift
@@ -24,7 +24,7 @@ extension StorageKeys {
         }
 
         var domain: StorageDomain {
-            .appGroupFileSystem(identifier: AppGroupConfiguration.identifier, directory: directory)
+            .appGroupFileSystem(identifier: StorageServiceIdentifiers.appGroupIdentifier, directory: directory)
         }
     }
 }
diff --git a/SecureStorgageSample/StorageKeys/AppGroup/UserPreferencesKey.swift b/SecureStorgageSample/StorageKeys/AppGroup/UserPreferencesKey.swift
index ec216bd..b36c426 100644
--- a/SecureStorgageSample/StorageKeys/AppGroup/UserPreferencesKey.swift
+++ b/SecureStorgageSample/StorageKeys/AppGroup/UserPreferencesKey.swift
@@ -1,5 +1,6 @@
 import Foundation
 import LocalData
+import SharedKit
 
 extension StorageKeys {
     /// Stores user preferences in App Group UserDefaults.
@@ -10,7 +11,7 @@ extension StorageKeys {
         typealias Value = [String: AnyCodable]
 
         let name = "user_preferences"
-        let domain: StorageDomain = .appGroupUserDefaults(identifier: AppGroupConfiguration.identifier)
+        let domain: StorageDomain = .appGroupUserDefaults(identifier: StorageServiceIdentifiers.appGroupIdentifier)
         let security: SecurityPolicy = .none
         let serializer: Serializer<[String: AnyCodable]> = .json
         let owner = "SampleApp"