diff --git a/Sources/XuqmSDK/License/DeviceInfoProvider.swift b/Sources/XuqmSDK/License/DeviceInfoProvider.swift
new file mode 100644
index 0000000..bdc87cb
--- /dev/null
+++ b/Sources/XuqmSDK/License/DeviceInfoProvider.swift
@@ -0,0 +1,45 @@
+#if canImport(UIKit)
+import UIKit
+#endif
+import Foundation
+
+enum DeviceInfoProvider {
+
+    static func getDeviceId(store: LicenseStore) -> String {
+        if let existing = store.deviceId { return existing }
+        #if canImport(UIKit)
+        let id = UIDevice.current.identifierForVendor?.uuidString ?? UUID().uuidString
+        #else
+        let id = UUID().uuidString
+        #endif
+        store.deviceId = id
+        return id
+    }
+
+    static func getDeviceName() -> String {
+        #if canImport(UIKit)
+        return UIDevice.current.name
+        #else
+        return Host.current().localizedName ?? "Mac"
+        #endif
+    }
+
+    static func getDeviceModel() -> String {
+        #if canImport(UIKit)
+        return UIDevice.current.model
+        #else
+        return "Mac"
+        #endif
+    }
+
+    static func getDeviceVendor() -> String { "Apple" }
+
+    static func getOsVersion() -> String {
+        #if canImport(UIKit)
+        return "iOS \(UIDevice.current.systemVersion)"
+        #else
+        let v = ProcessInfo.processInfo.operatingSystemVersion
+        return "macOS \(v.majorVersion).\(v.minorVersion).\(v.patchVersion)"
+        #endif
+    }
+}
diff --git a/Sources/XuqmSDK/License/LicenseFileCrypto.swift b/Sources/XuqmSDK/License/LicenseFileCrypto.swift
new file mode 100644
index 0000000..1482bbd
--- /dev/null
+++ b/Sources/XuqmSDK/License/LicenseFileCrypto.swift
@@ -0,0 +1,66 @@
+import Foundation
+import CryptoKit
+import CommonCrypto
+
+enum LicenseFileCryptoError: Error {
+    case invalidFormat
+    case keyDerivationFailed
+    case decryptionFailed
+}
+
+enum LicenseFileCrypto {
+    private static let magic = "XUQM-LICENSE-V1"
+    private static let passphrase = "xuqm-license-file-v1.2026.internal"
+    private static let keyByteCount = 32
+    private static let pbkdf2Iterations: UInt32 = 120_000
+
+    // Format: MAGIC.base64UrlSalt.base64UrlIV.base64UrlCiphertext
+    // Base64: URL-safe, no padding, no wrap
+    // Algorithm: AES/GCM/NoPadding, PBKDF2WithHmacSHA256, 256-bit key, 128-bit tag
+    static func decrypt(_ content: String) throws -> String {
+        let parts = content.trimmingCharacters(in: .whitespacesAndNewlines).components(separatedBy: ".")
+        guard parts.count == 4, parts[0] == magic else {
+            throw LicenseFileCryptoError.invalidFormat
+        }
+        guard let salt = base64UrlDecode(parts[1]),
+              let iv = base64UrlDecode(parts[2]),
+              let ciphertext = base64UrlDecode(parts[3]) else {
+            throw LicenseFileCryptoError.invalidFormat
+        }
+        let key = try deriveKey(salt: salt)
+        // CryptoKit SealedBox(combined:) expects nonce(12) || ciphertext || tag(16)
+        // Android JCE appends the 16-byte GCM tag at end of ciphertext — matches this format exactly
+        let combined = iv + ciphertext
+        let sealedBox = try AES.GCM.SealedBox(combined: combined)
+        let decrypted = try AES.GCM.open(sealedBox, using: key)
+        guard let plaintext = String(data: decrypted, encoding: .utf8) else {
+            throw LicenseFileCryptoError.decryptionFailed
+        }
+        return plaintext
+    }
+
+    private static func deriveKey(salt: Data) throws -> SymmetricKey {
+        let passphraseBytes = Array(passphrase.utf8)
+        let saltBytes = Array(salt)
+        var derivedKey = [UInt8](repeating: 0, count: keyByteCount)
+        let status = CCKeyDerivationPBKDF(
+            CCPBKDFAlgorithm(kCCPBKDF2),
+            passphrase, passphraseBytes.count,
+            saltBytes, saltBytes.count,
+            CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA256),
+            pbkdf2Iterations,
+            &derivedKey, keyByteCount
+        )
+        guard status == kCCSuccess else {
+            throw LicenseFileCryptoError.keyDerivationFailed
+        }
+        return SymmetricKey(data: Data(derivedKey))
+    }
+
+    private static func base64UrlDecode(_ value: String) -> Data? {
+        var s = value.replacingOccurrences(of: "-", with: "+").replacingOccurrences(of: "_", with: "/")
+        let rem = s.count % 4
+        if rem > 0 { s += String(repeating: "=", count: 4 - rem) }
+        return Data(base64Encoded: s)
+    }
+}
diff --git a/Sources/XuqmSDK/License/LicenseFileReader.swift b/Sources/XuqmSDK/License/LicenseFileReader.swift
new file mode 100644
index 0000000..ecdc51d
--- /dev/null
+++ b/Sources/XuqmSDK/License/LicenseFileReader.swift
@@ -0,0 +1,21 @@
+import Foundation
+
+enum LicenseFileReader {
+
+    static func read() -> LicenseFile? {
+        guard let url = Bundle.main.url(forResource: "license", withExtension: "xuqm", subdirectory: "xuqm"),
+              let encrypted = try? String(contentsOf: url, encoding: .utf8) else {
+            return nil
+        }
+        return parse(encrypted)
+    }
+
+    static func parse(_ encrypted: String) -> LicenseFile? {
+        guard let json = try? LicenseFileCrypto.decrypt(encrypted),
+              let data = json.data(using: .utf8),
+              let file = try? JSONDecoder().decode(LicenseFile.self, from: data) else {
+            return nil
+        }
+        return file
+    }
+}
diff --git a/Sources/XuqmSDK/License/LicenseModels.swift b/Sources/XuqmSDK/License/LicenseModels.swift
new file mode 100644
index 0000000..0db7507
--- /dev/null
+++ b/Sources/XuqmSDK/License/LicenseModels.swift
@@ -0,0 +1,70 @@
+import Foundation
+
+struct LicenseFile: Codable {
+    let appKey: String
+    let appName: String?
+    let companyName: String?
+    let baseUrl: String?
+    let issuedAt: String?
+    let expiresAt: String?
+}
+
+public struct LicenseUserInfo: Sendable {
+    public let userId: String?
+    public let name: String?
+    public let email: String?
+    public let phone: String?
+
+    public init(userId: String? = nil, name: String? = nil, email: String? = nil, phone: String? = nil) {
+        self.userId = userId
+        self.name = name
+        self.email = email
+        self.phone = phone
+    }
+}
+
+public enum LicenseStatus: Sendable {
+    case ok
+    case denied
+    case unknown
+}
+
+public enum LicenseResult: Sendable {
+    case success(String)
+    case error(String)
+}
+
+struct UserInfoPayload: Encodable {
+    let userId: String?
+    let name: String?
+    let email: String?
+    let phone: String?
+}
+
+struct RegisterRequest: Encodable {
+    let appKey: String
+    let deviceId: String
+    let deviceName: String?
+    let deviceModel: String
+    let deviceVendor: String
+    let osVersion: String
+    let userInfo: UserInfoPayload?
+}
+
+struct VerifyRequest: Encodable {
+    let appKey: String
+    let deviceId: String
+    let token: String
+    let userInfo: UserInfoPayload?
+}
+
+struct RegisterResponse: Decodable {
+    let success: Bool
+    let token: String?
+    let message: String?
+}
+
+struct VerifyResponse: Decodable {
+    let valid: Bool
+    let error: String?
+}
diff --git a/Sources/XuqmSDK/License/LicenseSDK.swift b/Sources/XuqmSDK/License/LicenseSDK.swift
new file mode 100644
index 0000000..f4a3c88
--- /dev/null
+++ b/Sources/XuqmSDK/License/LicenseSDK.swift
@@ -0,0 +1,131 @@
+import Foundation
+
+public final class LicenseSDK: @unchecked Sendable {
+
+    public static let shared = LicenseSDK()
+
+    private static let defaultBaseUrl = "https://auth.dev.xuqinmin.com/"
+    private static let statusOk = "ok"
+    private static let statusDenied = "denied"
+    private static let cacheWindowMs: Double = 10 * 60 * 1000
+
+    private var appKey: String?
+    private var baseUrl: String = defaultBaseUrl
+    private var deviceName: String?
+    private let store = LicenseStore()
+    private var initialized = false
+
+    private init() {}
+
+    /// Manual initialization. Most apps only need to place the license file at
+    /// assets/xuqm/license.xuqm (bundle) and call checkLicense() — auto-init handles the rest.
+    public func initialize(appKey: String, baseUrl: String? = nil, deviceName: String? = nil) {
+        let url = normalize(baseUrl ?? Self.defaultBaseUrl)
+        if store.appKey != nil && store.appKey != appKey { store.clear() }
+        self.appKey = appKey
+        self.baseUrl = url
+        self.deviceName = deviceName ?? DeviceInfoProvider.getDeviceName()
+        store.appKey = appKey
+        initialized = true
+    }
+
+    /// Check license validity. Returns cached result within 10-minute window.
+    /// On network error, falls back to last cached OK status.
+    public func checkLicense(userInfo: LicenseUserInfo? = nil) async -> LicenseResult {
+        if !initialized { tryAutoInitialize() }
+        guard initialized, let appKey else {
+            return .error("LicenseSDK not initialized")
+        }
+
+        let cachedStatus = store.status
+        let cachedTime = store.statusTime
+        if cachedStatus == Self.statusOk && (Date().timeIntervalSince1970 * 1000 - cachedTime) < Self.cacheWindowMs {
+            return .success("Cached")
+        }
+
+        let deviceId = DeviceInfoProvider.getDeviceId(store: store)
+        let payload = userInfo.map { UserInfoPayload(userId: $0.userId, name: $0.name, email: $0.email, phone: $0.phone) }
+
+        do {
+            if let token = store.token {
+                let req = VerifyRequest(appKey: appKey, deviceId: deviceId, token: token, userInfo: payload)
+                if let resp = try? await post(VerifyResponse.self, path: "api/license/verify", body: req), resp.valid {
+                    persistStatus(Self.statusOk)
+                    return .success("Verified")
+                }
+                store.token = nil
+            }
+
+            let req = RegisterRequest(
+                appKey: appKey,
+                deviceId: deviceId,
+                deviceName: deviceName ?? DeviceInfoProvider.getDeviceName(),
+                deviceModel: DeviceInfoProvider.getDeviceModel(),
+                deviceVendor: DeviceInfoProvider.getDeviceVendor(),
+                osVersion: DeviceInfoProvider.getOsVersion(),
+                userInfo: payload
+            )
+            let resp = try await post(RegisterResponse.self, path: "api/license/register", body: req)
+            if resp.success, let token = resp.token {
+                store.token = token
+                persistStatus(Self.statusOk)
+                return .success("Registered")
+            }
+            persistStatus(Self.statusDenied)
+            return .error(resp.message ?? "Registration denied")
+        } catch {
+            if cachedStatus == Self.statusOk { return .success("Offline - cached ok") }
+            return .error(error.localizedDescription)
+        }
+    }
+
+    public func getStatus() -> LicenseStatus {
+        if !initialized { tryAutoInitialize() }
+        switch store.status {
+        case Self.statusOk: return .ok
+        case Self.statusDenied: return .denied
+        default: return .unknown
+        }
+    }
+
+    public func getDeviceId() -> String? {
+        if !initialized && !tryAutoInitialize() { return nil }
+        return store.deviceId
+    }
+
+    public func clear() { store.clear() }
+
+    @discardableResult
+    private func tryAutoInitialize() -> Bool {
+        guard let file = LicenseFileReader.read(), !file.appKey.isEmpty else { return false }
+        initialize(appKey: file.appKey, baseUrl: file.baseUrl)
+        return true
+    }
+
+    private func persistStatus(_ status: String) {
+        store.status = status
+        store.statusTime = Date().timeIntervalSince1970 * 1000
+    }
+
+    private func normalize(_ url: String) -> String {
+        let s = url.trimmingCharacters(in: .whitespaces)
+        return s.hasSuffix("/") ? s : s + "/"
+    }
+
+    private func post<T: Decodable, B: Encodable>(_ type: T.Type, path: String, body: B) async throws -> T {
+        guard let url = URL(string: baseUrl + path) else { throw URLError(.badURL) }
+        var req = URLRequest(url: url)
+        req.httpMethod = "POST"
+        req.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        req.httpBody = try JSONEncoder().encode(body)
+        let (data, response) = try await URLSession.shared.data(for: req)
+        guard let http = response as? HTTPURLResponse, (200..<300).contains(http.statusCode) else {
+            throw URLError(.badServerResponse)
+        }
+        struct Wrapper<U: Decodable>: Decodable { let data: U? }
+        guard let wrapper = try? JSONDecoder().decode(Wrapper<T>.self, from: data), let result = wrapper.data else {
+            throw URLError(.cannotDecodeContentData)
+        }
+        return result
+    }
+}
diff --git a/Sources/XuqmSDK/License/LicenseStore.swift b/Sources/XuqmSDK/License/LicenseStore.swift
new file mode 100644
index 0000000..4a566e6
--- /dev/null
+++ b/Sources/XuqmSDK/License/LicenseStore.swift
@@ -0,0 +1,85 @@
+import Foundation
+import Security
+
+final class LicenseStore {
+    private let keychainService = "com.xuqm.license"
+    private let defaults: UserDefaults
+
+    init() {
+        defaults = UserDefaults(suiteName: "xuqm_license") ?? .standard
+    }
+
+    var token: String? {
+        get { keychainGet("token") }
+        set { keychainSet("token", value: newValue) }
+    }
+
+    var deviceId: String? {
+        get { keychainGet("deviceId") }
+        set { keychainSet("deviceId", value: newValue) }
+    }
+
+    var status: String? {
+        get { defaults.string(forKey: "status") }
+        set { defaults.set(newValue, forKey: "status") }
+    }
+
+    // Stored as Double (milliseconds since epoch) to match Android's currentTimeMillis
+    var statusTime: Double {
+        get { defaults.double(forKey: "statusTime") }
+        set { defaults.set(newValue, forKey: "statusTime") }
+    }
+
+    var appKey: String? {
+        get { defaults.string(forKey: "appKey") }
+        set { defaults.set(newValue, forKey: "appKey") }
+    }
+
+    func clear() {
+        token = nil
+        deviceId = nil
+        status = nil
+        statusTime = 0
+        appKey = nil
+    }
+
+    private func keychainGet(_ key: String) -> String? {
+        let query: [CFString: Any] = [
+            kSecClass: kSecClassGenericPassword,
+            kSecAttrService: keychainService,
+            kSecAttrAccount: key,
+            kSecReturnData: true,
+            kSecMatchLimit: kSecMatchLimitOne,
+        ]
+        var result: AnyObject?
+        guard SecItemCopyMatching(query as CFDictionary, &result) == errSecSuccess,
+              let data = result as? Data else { return nil }
+        return String(data: data, encoding: .utf8)
+    }
+
+    private func keychainSet(_ key: String, value: String?) {
+        guard let value else { keychainDelete(key); return }
+        let data = Data(value.utf8)
+        let query: [CFString: Any] = [
+            kSecClass: kSecClassGenericPassword,
+            kSecAttrService: keychainService,
+            kSecAttrAccount: key,
+        ]
+        if SecItemCopyMatching(query as CFDictionary, nil) == errSecSuccess {
+            SecItemUpdate(query as CFDictionary, [kSecValueData: data] as CFDictionary)
+        } else {
+            var item = query
+            item[kSecValueData] = data
+            SecItemAdd(item as CFDictionary, nil)
+        }
+    }
+
+    private func keychainDelete(_ key: String) {
+        let query: [CFString: Any] = [
+            kSecClass: kSecClassGenericPassword,
+            kSecAttrService: keychainService,
+            kSecAttrAccount: key,
+        ]
+        SecItemDelete(query as CFDictionary)
+    }
+}