From 07bcbf0c08a0b2246f9ae0c17c25b195fbca4ce3 Mon Sep 17 00:00:00 2001
From: Yaojia Wang <yaojia.wang@colacoder.com>
Date: Sat, 18 Jul 2026 13:32:05 +0200
Subject: [PATCH] feat(ios): device enrollment flow + silent cert rotation (B3)

Wire the SecureEnclave enroll library into a real flow (login->bearer->CSR->
/device/enroll->keychain identity), presented on the existing mTLS path; add a
rotation scheduler. Atomic keychain replace (add-before-delete); renew body is
{csr}-only; renewal-failing surfaced in the UI. ClientTLS 48 tests pass.
---
 .../WebTerm/Screens/EnrollmentScreen.swift    | 275 ++++++++++++++++++
 .../WebTerm/Screens/SessionListScreen.swift   |  12 +
 ios/App/WebTerm/Wiring/AdaptiveRootView.swift |  23 ++
 ios/App/WebTerm/Wiring/AppCoordinator.swift   |  61 ++++
 .../Wiring/DeviceEnrollmentWiring.swift       |  90 ++++++
 ios/App/WebTerm/Wiring/RootView.swift         |  43 ++-
 ios/App/WebTerm/Wiring/SplitRootView.swift    |   3 +-
 .../EnrollmentViewModelTests.swift            | 142 +++++++++
 .../CertificateRotationScheduler.swift        | 107 +++++++
 .../ClientTLS/ControlPlaneLoginClient.swift   | 108 +++++++
 .../ClientTLS/DeviceEnrollmentClient.swift    |  24 +-
 .../ClientTLS/DeviceEnrollmentFlow.swift      |  63 ++++
 .../KeychainClientIdentityStore.swift         | 115 ++++++--
 .../ClientTLS/KeychainItemReplace.swift       |  30 ++
 .../CertificateRotationSchedulerTests.swift   | 107 +++++++
 .../ControlPlaneLoginClientTests.swift        | 123 ++++++++
 .../DeviceEnrollmentClientTests.swift         |  43 +++
 .../DeviceEnrollmentFlowTests.swift           | 136 +++++++++
 .../KeychainItemReplaceTests.swift            |  76 +++++
 19 files changed, 1549 insertions(+), 32 deletions(-)
 create mode 100644 ios/App/WebTerm/Screens/EnrollmentScreen.swift
 create mode 100644 ios/App/WebTerm/Wiring/DeviceEnrollmentWiring.swift
 create mode 100644 ios/App/WebTermTests/EnrollmentViewModelTests.swift
 create mode 100644 ios/Packages/ClientTLS/Sources/ClientTLS/CertificateRotationScheduler.swift
 create mode 100644 ios/Packages/ClientTLS/Sources/ClientTLS/ControlPlaneLoginClient.swift
 create mode 100644 ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentFlow.swift
 create mode 100644 ios/Packages/ClientTLS/Sources/ClientTLS/KeychainItemReplace.swift
 create mode 100644 ios/Packages/ClientTLS/Tests/ClientTLSTests/CertificateRotationSchedulerTests.swift
 create mode 100644 ios/Packages/ClientTLS/Tests/ClientTLSTests/ControlPlaneLoginClientTests.swift
 create mode 100644 ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentFlowTests.swift
 create mode 100644 ios/Packages/ClientTLS/Tests/ClientTLSTests/KeychainItemReplaceTests.swift

diff --git a/ios/App/WebTerm/Screens/EnrollmentScreen.swift b/ios/App/WebTerm/Screens/EnrollmentScreen.swift
new file mode 100644
index 0000000..068f6d1
--- /dev/null
+++ b/ios/App/WebTerm/Screens/EnrollmentScreen.swift
@@ -0,0 +1,275 @@
+import ClientTLS
+import Foundation
+import Observation
+import SwiftUI
+import UIKit
+import WireProtocol
+
+/// B3 · Zero-`.p12` device-enrollment screen — the phone half of zero-touch.
+///
+/// Flow: one operator login → a short-lived `device:enroll` bearer → a
+/// NON-EXPORTABLE Secure-Enclave key + PKCS#10 CSR → `POST /device/enroll` →
+/// the returned leaf is stored against the SE key and presents AUTOMATICALLY on
+/// the existing mTLS path (no manual certificate import, ever). After this one
+/// login the cert renews itself silently (`CertificateRotationScheduler`).
+///
+/// Pure presentation over `EnrollmentViewModel`; validation, the flow, and error
+/// mapping live in the VM. Presented from the host-menu ("自动获取证书").
+struct EnrollmentScreen: View {
+    @State private var model: EnrollmentViewModel
+
+    init(model: EnrollmentViewModel) {
+        _model = State(initialValue: model)
+    }
+
+    var body: some View {
+        Form {
+            installedSection
+            enrollSection
+        }
+        .navigationTitle(EnrollmentCopy.title)
+        .task { model.refresh() }
+    }
+
+    // MARK: - Sections
+
+    @ViewBuilder private var installedSection: some View {
+        Section(EnrollmentCopy.installedHeader) {
+            if let summary = model.summary {
+                LabeledContent(EnrollmentCopy.subject, value: summary.subjectCommonName ?? "—")
+                LabeledContent(EnrollmentCopy.issuer, value: summary.issuerCommonName ?? "—")
+                LabeledContent(EnrollmentCopy.expiry, value: model.expiryText(summary))
+                if summary.isExpired() {
+                    Label(EnrollmentCopy.expiredWarning, systemImage: "exclamationmark.triangle")
+                        .foregroundStyle(.orange)
+                }
+            } else {
+                Text(EnrollmentCopy.noneInstalled).foregroundStyle(.secondary)
+            }
+        }
+    }
+
+    @ViewBuilder private var enrollSection: some View {
+        Section {
+            TextField(EnrollmentCopy.controlPlaneURL, text: $model.controlPlaneURLText)
+                .textContentType(.URL)
+                .keyboardType(.URL)
+                .textInputAutocapitalization(.never)
+                .autocorrectionDisabled()
+            TextField(EnrollmentCopy.subdomain, text: $model.subdomain)
+                .textInputAutocapitalization(.never)
+                .autocorrectionDisabled()
+            TextField(EnrollmentCopy.deviceName, text: $model.deviceName)
+            SecureField(EnrollmentCopy.password, text: $model.password)
+                .textContentType(.password)
+                .autocorrectionDisabled()
+            Button {
+                Task { await model.enroll() }
+            } label: {
+                if model.isEnrolling {
+                    ProgressView()
+                } else {
+                    Label(
+                        model.summary == nil
+                            ? EnrollmentCopy.enrollAction
+                            : EnrollmentCopy.rotateAction,
+                        systemImage: "checkmark.shield"
+                    )
+                }
+            }
+            .disabled(!model.canEnroll)
+            .accessibilityIdentifier("enroll.submit")
+
+            if let error = model.errorMessage {
+                Text(error).foregroundStyle(.red).font(.footnote)
+            }
+            if model.didSucceed {
+                Label(EnrollmentCopy.success, systemImage: "checkmark.circle.fill")
+                    .foregroundStyle(.green).font(.footnote)
+            }
+        } header: {
+            Text(model.summary == nil ? EnrollmentCopy.enrollHeader : EnrollmentCopy.rotateHeader)
+        } footer: {
+            Text(EnrollmentCopy.footer)
+        }
+    }
+}
+
+/// B3 · Enrollment state machine. Validates inputs at the boundary, drives
+/// `DeviceEnrollmentFlow`, and maps every failure to actionable copy — never
+/// swallowed, never leaking the password or bearer.
+@MainActor
+@Observable
+final class EnrollmentViewModel {
+    /// The enroll operation: login → SE keygen+CSR → enroll → store. Injected so
+    /// the VM is unit-testable without a keychain / network (production wires it
+    /// to `DeviceEnrollmentFlow`).
+    typealias EnrollOperation = @Sendable (
+        _ password: String, _ subdomain: String, _ deviceName: String, _ controlPlaneURL: URL
+    ) async throws -> ClientCertificateSummary?
+
+    var controlPlaneURLText: String
+    var subdomain: String
+    var deviceName: String
+    var password = ""
+
+    private(set) var summary: ClientCertificateSummary?
+    private(set) var isEnrolling = false
+    private(set) var didSucceed = false
+    private(set) var errorMessage: String?
+
+    @ObservationIgnored private let enrollOperation: EnrollOperation
+    @ObservationIgnored private let loadSummary: @Sendable () -> ClientCertificateSummary?
+    @ObservationIgnored private let persistSettings: @Sendable (_ url: String, _ subdomain: String) -> Void
+
+    init(
+        controlPlaneURLText: String = EnrollmentSettings.controlPlaneURL ?? EnrollmentCopy.defaultControlPlaneURL,
+        subdomain: String = EnrollmentSettings.subdomain ?? "",
+        deviceName: String = UIDevice.current.name,
+        enrollOperation: @escaping EnrollOperation,
+        loadSummary: @escaping @Sendable () -> ClientCertificateSummary?,
+        persistSettings: @escaping @Sendable (_ url: String, _ subdomain: String) -> Void = { url, sub in
+            EnrollmentSettings.controlPlaneURL = url
+            EnrollmentSettings.subdomain = sub
+        }
+    ) {
+        self.controlPlaneURLText = controlPlaneURLText
+        self.subdomain = subdomain
+        self.deviceName = deviceName
+        self.enrollOperation = enrollOperation
+        self.loadSummary = loadSummary
+        self.persistSettings = persistSettings
+    }
+
+    /// Fields all present → the button is enabled (deeper URL validation on tap).
+    var canEnroll: Bool {
+        !isEnrolling
+            && !controlPlaneURLText.trimmed.isEmpty
+            && !subdomain.trimmed.isEmpty
+            && !deviceName.trimmed.isEmpty
+            && !password.isEmpty
+    }
+
+    func refresh() {
+        summary = loadSummary()
+    }
+
+    func expiryText(_ summary: ClientCertificateSummary) -> String {
+        guard let notAfter = summary.notAfter else { return "—" }
+        return notAfter.formatted(date: .abbreviated, time: .omitted)
+    }
+
+    /// Run enrollment. Validates the control-plane URL (must be https with a
+    /// host) before any network, then drives the flow. The password is cleared
+    /// after every attempt (success OR failure) so it never lingers in memory.
+    func enroll() async {
+        errorMessage = nil
+        didSucceed = false
+        let trimmedURL = controlPlaneURLText.trimmed
+        let trimmedSubdomain = subdomain.trimmed
+        let trimmedName = deviceName.trimmed
+        guard let url = URL(string: trimmedURL),
+              url.scheme?.lowercased() == "https",
+              let host = url.host, !host.isEmpty else {
+            errorMessage = EnrollmentCopy.errInvalidURL
+            return
+        }
+        guard !trimmedSubdomain.isEmpty, !trimmedName.isEmpty, !password.isEmpty else {
+            errorMessage = EnrollmentCopy.errMissingFields
+            return
+        }
+        isEnrolling = true
+        defer { isEnrolling = false }
+        let secret = password
+        do {
+            summary = try await enrollOperation(secret, trimmedSubdomain, trimmedName, url)
+            persistSettings(trimmedURL, trimmedSubdomain)
+            password = "" // never linger after success
+            didSucceed = true
+            refresh()
+        } catch {
+            password = "" // never linger after failure either
+            errorMessage = Self.copy(for: error)
+        }
+    }
+
+    /// Map a login/enroll/keychain error to enrollment-UX copy (never swallowed,
+    /// never containing the password/token).
+    private static func copy(for error: any Error) -> String {
+        switch error {
+        case ControlPlaneLoginError.emptyPassword:
+            return EnrollmentCopy.errEmptyPassword
+        case ControlPlaneLoginError.http(let status, _) where status == 401:
+            return EnrollmentCopy.errBadCredential
+        case ControlPlaneLoginError.http:
+            return EnrollmentCopy.errLoginFailed
+        case ControlPlaneLoginError.malformedResponse:
+            return EnrollmentCopy.errServer
+        case DeviceEnrollmentError.http(let status, _) where status == 403:
+            return EnrollmentCopy.errSubdomainNotOwned
+        case DeviceEnrollmentError.http(let status, _) where status == 429:
+            return EnrollmentCopy.errRateLimited
+        case DeviceEnrollmentError.http(let status, _) where status == 400:
+            return EnrollmentCopy.errRejected
+        case DeviceEnrollmentError.http:
+            return EnrollmentCopy.errEnrollFailed
+        case DeviceEnrollmentError.malformedResponse:
+            return EnrollmentCopy.errServer
+        case SecureEnclaveKeyError.secureEnclaveUnavailable:
+            return EnrollmentCopy.errNoSecureEnclave
+        case is SecureEnclaveKeyError:
+            return EnrollmentCopy.errKeygen
+        case ClientIdentityStoreError.keychain, ClientIdentityStoreError.corruptStoredBlob:
+            return EnrollmentCopy.errKeychain
+        case DeviceEnrollmentWiringError.missingControlPlaneURL,
+             DeviceEnrollmentWiringError.invalidControlPlaneURL:
+            return EnrollmentCopy.errInvalidURL
+        default:
+            return EnrollmentCopy.errUnknown
+        }
+    }
+}
+
+private extension String {
+    var trimmed: String { trimmingCharacters(in: .whitespacesAndNewlines) }
+}
+
+/// User-facing copy (Chinese, matching the rest of the app).
+enum EnrollmentCopy {
+    static let defaultControlPlaneURL = "https://cp.terminal.yaojia.wang"
+
+    static let title = "自动获取证书"
+    static let installedHeader = "已安装证书"
+    static let subject = "设备 (CN)"
+    static let issuer = "签发 CA"
+    static let expiry = "有效期至"
+    static let expiredWarning = "证书已过期，请重新注册。"
+    static let noneInstalled = "尚未安装设备证书。"
+
+    static let enrollHeader = "注册本设备"
+    static let rotateHeader = "重新注册"
+    static let controlPlaneURL = "控制面地址"
+    static let subdomain = "子域名 (你拥有的隧道名)"
+    static let deviceName = "设备名称"
+    static let password = "操作口令"
+    static let enrollAction = "注册本设备"
+    static let rotateAction = "重新注册"
+    static let success = "已注册，证书已保存到本设备安全区。"
+    static let footer =
+        "首次登录一次即可：本设备在安全区 (Secure Enclave) 生成不可导出的私钥，向控制面申请证书并自动保存；之后连接隧道主机时自动出示，证书到期前会自动续期，无需再手动导入 .p12。"
+
+    static let errInvalidURL = "控制面地址无效，请输入 https:// 开头的完整地址。"
+    static let errMissingFields = "请填写子域名、设备名称和操作口令。"
+    static let errEmptyPassword = "请输入操作口令。"
+    static let errBadCredential = "操作口令错误，请重试。"
+    static let errLoginFailed = "登录失败，请稍后重试。"
+    static let errSubdomainNotOwned = "该账号未拥有此子域名，无法签发证书。"
+    static let errRateLimited = "请求过于频繁，请稍后再试。"
+    static let errRejected = "请求被拒绝：子域名或证书请求无效。"
+    static let errEnrollFailed = "注册失败，请稍后重试。"
+    static let errNoSecureEnclave = "本设备不支持安全区 (Secure Enclave)（模拟器？），无法生成硬件密钥。"
+    static let errKeygen = "生成硬件密钥失败，请重试。"
+    static let errKeychain = "保存到钥匙串失败，请重试。"
+    static let errServer = "服务器返回异常，请稍后重试。"
+    static let errUnknown = "注册失败，请重试。"
+}
diff --git a/ios/App/WebTerm/Screens/SessionListScreen.swift b/ios/App/WebTerm/Screens/SessionListScreen.swift
index 7113323..d04ebe5 100644
--- a/ios/App/WebTerm/Screens/SessionListScreen.swift
+++ b/ios/App/WebTerm/Screens/SessionListScreen.swift
@@ -29,6 +29,11 @@ struct SessionListScreen: View {
     /// settings-like surface and is present in every empty state, so this is the
     /// nav idiom that makes the orphaned screen reachable.
     var onDeviceCert: () -> Void = {}
+    /// B3 · "自动获取证书" entry — presents `EnrollmentScreen` (the zero-`.p12`
+    /// enrollment flow: login → Secure-Enclave key + CSR → device cert). Same
+    /// host-menu surface as `onDeviceCert`; that screen imports a `.p12`, this
+    /// one obtains a hardware-bound cert with no file at all.
+    var onEnroll: () -> Void = {}
     /// T-iOS-28 (additive slot) · shared thumbnail pipeline: one cache + one
     /// render-concurrency gate across ALL rows (scrolling must never spawn
     /// unbounded offscreen terminals). `@State` keeps it stable across body
@@ -219,6 +224,12 @@ struct SessionListScreen: View {
                 } label: {
                     Label(ScreenCopy.addHost, systemImage: "plus")
                 }
+                Button {
+                    onEnroll()
+                } label: {
+                    Label(ScreenCopy.enroll, systemImage: "checkmark.shield")
+                }
+                .accessibilityIdentifier("sessions.enroll")
                 Button {
                     onDeviceCert()
                 } label: {
@@ -355,6 +366,7 @@ private enum ScreenCopy {
     static let kill = "结束"
     static let addHost = "配对新主机"
     static let deviceCert = "设备证书"
+    static let enroll = "自动获取证书"
     static let hostMenuFallback = "主机"
     static let notPairedTitle = "还没有配对的主机"
     static let notPairedHint = "先配对你电脑上的 web-terminal（扫码或手输地址），会话会出现在这里。"
diff --git a/ios/App/WebTerm/Wiring/AdaptiveRootView.swift b/ios/App/WebTerm/Wiring/AdaptiveRootView.swift
index 716e380..b91f9da 100644
--- a/ios/App/WebTerm/Wiring/AdaptiveRootView.swift
+++ b/ios/App/WebTerm/Wiring/AdaptiveRootView.swift
@@ -54,6 +54,12 @@ struct AdaptiveRootView: View {
         .sheet(isPresented: $coordinator.isDeviceCertPresented) {
             deviceCertSheet
         }
+        .sheet(
+            isPresented: $coordinator.isEnrollmentPresented,
+            onDismiss: { coordinator.enrollmentDismissed() }
+        ) {
+            enrollmentSheet
+        }
     }
 
     // MARK: - Layout branch (the SOLE size-class consumer)
@@ -126,4 +132,21 @@ struct AdaptiveRootView: View {
                 }
         }
     }
+
+    // MARK: - Device enrollment sheet (B3, zero-.p12 auto-cert)
+
+    /// 自带 NavigationStack + 右上「完成」。VM 由 coordinator 每次进入构建
+    /// （`presentEnrollment`）；关闭后 `enrollmentDismissed` 丢弃 VM 并跑一次轮换。
+    @ViewBuilder private var enrollmentSheet: some View {
+        if let viewModel = coordinator.enrollmentViewModel {
+            NavigationStack {
+                EnrollmentScreen(model: viewModel)
+                    .toolbar {
+                        ToolbarItem(placement: .topBarTrailing) {
+                            Button(RootCopy.done) { coordinator.isEnrollmentPresented = false }
+                        }
+                    }
+            }
+        }
+    }
 }
diff --git a/ios/App/WebTerm/Wiring/AppCoordinator.swift b/ios/App/WebTerm/Wiring/AppCoordinator.swift
index 0f1b30e..ed457e0 100644
--- a/ios/App/WebTerm/Wiring/AppCoordinator.swift
+++ b/ios/App/WebTerm/Wiring/AppCoordinator.swift
@@ -1,3 +1,4 @@
+import ClientTLS
 import Foundation
 import HostRegistry
 import Observation
@@ -36,6 +37,20 @@ final class AppCoordinator {
     /// its own `ClientCertViewModel` over the keychain store; dismissal needs no
     /// refresh because the transports resolve the identity lazily per connection.
     var isDeviceCertPresented = false
+    /// B3 · "自动获取证书" sheet — the zero-`.p12` enrollment flow
+    /// (`EnrollmentScreen`): one login → Secure-Enclave key + CSR → device cert,
+    /// presented automatically on the existing mTLS path. VM built per entry.
+    var isEnrollmentPresented = false
+    private(set) var enrollmentViewModel: EnrollmentViewModel?
+    /// B3 · Re-entrancy guard so overlapping foregrounds never launch two silent
+    /// renews at once (a shared PTY-style single-flight for the rotation pass).
+    @ObservationIgnored private var isRotating = false
+    /// B3 (HIGH observability fix) · Persistent, OBSERVABLE flag: the last silent
+    /// rotation pass ended in `.failed` (keychain read fault or renew error). Set
+    /// alongside the os.Logger line so a silently-failing renewal surfaces to the
+    /// UI (a warning banner) instead of vanishing into the log. Cleared by the
+    /// next non-failed pass — a recovered renewal drops the warning automatically.
+    private(set) var isCertificateRenewalFailing = false
 
     let sessionList: SessionListViewModel
     @ObservationIgnored let environment: AppEnvironment
@@ -69,6 +84,7 @@ final class AppCoordinator {
         if route == .pairing {
             rootPairingViewModel = makePairingViewModel()
         }
+        runCertificateRotationIfDue() // B3 · renew a due device cert on cold launch
         await deepLink.markReady() // flush a cold-launch deep link (T-iOS-22)
     }
 
@@ -120,6 +136,50 @@ final class AppCoordinator {
         isDeviceCertPresented = true
     }
 
+    // MARK: - Device enrollment (B3, zero-.p12 auto-cert)
+
+    /// Toolbar host-menu 入口：呈现「自动获取证书」注册 sheet。VM 每次进入重建。
+    func presentEnrollment() {
+        enrollmentViewModel = makeEnrollmentViewModel()
+        isEnrollmentPresented = true
+    }
+
+    /// Sheet 消失：丢弃 VM，并立刻跑一次轮换检查（刚注册完的证书据此登记续期）。
+    func enrollmentDismissed() {
+        enrollmentViewModel = nil
+        runCertificateRotationIfDue()
+    }
+
+    /// 生产 VM：登录 → 安全区生成密钥+CSR → `/device/enroll` → 存钥匙串，全部经
+    /// `DeviceEnrollmentFlow`（复用 ClientTLS 库，本层零加密/钥匙串逻辑）。
+    private func makeEnrollmentViewModel() -> EnrollmentViewModel {
+        let http = environment.http
+        return EnrollmentViewModel(
+            enrollOperation: { password, subdomain, deviceName, url in
+                try await makeDeviceEnrollmentFlow(controlPlaneURL: url, http: http)
+                    .run(password: password, subdomain: subdomain, deviceName: deviceName)
+            },
+            loadSummary: { (try? KeychainClientIdentityStore().loadSummary()) ?? nil }
+        )
+    }
+
+    /// B3 · Silent rotation: check the installed leaf's timing and, if the renew
+    /// window has opened, renew over mTLS against the SAME Secure-Enclave key.
+    /// Fire-and-forget on launch + every foreground; single-flight via
+    /// `isRotating`. A `.notEnrolled` / `.notDue` pass is cheap and common.
+    func runCertificateRotationIfDue() {
+        guard !isRotating else { return }
+        isRotating = true
+        let scheduler = makeCertificateRotationScheduler(http: environment.http)
+        Task { [weak self] in
+            let outcome = await scheduler.runIfDue()
+            self?.isRotating = false
+            // Surface a silently-failing renewal as observable state (not only a
+            // log line); a later successful/not-due pass clears it.
+            self?.isCertificateRenewalFailing = (outcome == .failed)
+        }
+    }
+
     /// "在此仓库开新会话"：关 sheet → fresh spawn（`attach(null, cwd)`）+
     /// attach 后注入 `claude\r`（帧序由 engine 的 attach-first 队列保证）。
     func openProject(_ request: ProjectOpenRequest) {
@@ -290,6 +350,7 @@ final class AppCoordinator {
             terminalController?.suspend()
         case .active:
             terminalController?.resumeIfNeeded()
+            runCertificateRotationIfDue() // B3 · check for a due renewal each foreground
         case .inactive:
             break // transient; shade covers it at the view layer
         @unknown default:
diff --git a/ios/App/WebTerm/Wiring/DeviceEnrollmentWiring.swift b/ios/App/WebTerm/Wiring/DeviceEnrollmentWiring.swift
new file mode 100644
index 0000000..da15941
--- /dev/null
+++ b/ios/App/WebTerm/Wiring/DeviceEnrollmentWiring.swift
@@ -0,0 +1,90 @@
+import ClientTLS
+import Foundation
+import WireProtocol
+
+/// B3 · Production wiring that connects the ClientTLS enrollment library to the
+/// app's real transports. Kept in the assembly layer (not the leaf package) so
+/// `ClientTLS` stays dependency-free and unit-testable; here we only adapt types
+/// and read persisted config — no crypto, no keychain of our own.
+
+/// Adapts the app's `HTTPTransport` (WireProtocol) to `ClientTLS`'s
+/// `EnrollmentTransport`. The two protocols have an identical `send` shape; this
+/// one-line bridge lets the SAME `URLSessionHTTPTransport` — which already
+/// presents the device identity on a client-cert challenge (mTLS) — serve login,
+/// enroll AND the silent renew, so renew authenticates with the current cert.
+struct EnrollmentTransportAdapter: EnrollmentTransport {
+    private let http: any HTTPTransport
+
+    init(http: any HTTPTransport) {
+        self.http = http
+    }
+
+    func send(_ request: URLRequest) async throws -> (Data, HTTPURLResponse) {
+        try await http.send(request)
+    }
+}
+
+/// B3 · Non-secret enrollment config persisted for the silent rotation scheduler
+/// (the control-plane URL to renew against) and to prefill the re-enroll form.
+/// Namespaced statics over `UserDefaults.standard` — nothing secret is stored
+/// here (the bearer is never persisted; the private key stays in the Secure
+/// Enclave; the leaf/chain live in the keychain via `KeychainClientIdentityStore`).
+enum EnrollmentSettings {
+    private static let controlPlaneURLKey = "webterm.enroll.controlPlaneURL"
+    private static let subdomainKey = "webterm.enroll.subdomain"
+
+    static var controlPlaneURL: String? {
+        get { UserDefaults.standard.string(forKey: controlPlaneURLKey) }
+        set { UserDefaults.standard.set(newValue, forKey: controlPlaneURLKey) }
+    }
+
+    static var subdomain: String? {
+        get { UserDefaults.standard.string(forKey: subdomainKey) }
+        set { UserDefaults.standard.set(newValue, forKey: subdomainKey) }
+    }
+}
+
+enum DeviceEnrollmentWiringError: Error, Equatable, Sendable {
+    /// The control-plane URL is missing/invalid — cannot build a renew client.
+    case missingControlPlaneURL
+    /// The typed control-plane URL is not a valid absolute URL.
+    case invalidControlPlaneURL
+}
+
+/// Build the enrollment flow (login → SE keygen+CSR → enroll → store) against the
+/// given control-plane URL, reusing the app's mTLS-capable transport.
+func makeDeviceEnrollmentFlow(
+    controlPlaneURL: URL,
+    http: any HTTPTransport,
+    store: KeychainClientIdentityStore = KeychainClientIdentityStore()
+) -> DeviceEnrollmentFlow {
+    DeviceEnrollmentFlow(
+        baseURL: controlPlaneURL,
+        transport: EnrollmentTransportAdapter(http: http),
+        store: store
+    )
+}
+
+/// Build the silent rotation scheduler. `renewalState` reads the installed leaf's
+/// timing; `performRenew` re-CSRs from the SAME Secure-Enclave key and POSTs
+/// `/device/:id/renew` over mTLS (nil bearer — the current cert authenticates).
+/// The control-plane URL is read fresh from `EnrollmentSettings` at renew time.
+func makeCertificateRotationScheduler(
+    http: any HTTPTransport,
+    store: KeychainClientIdentityStore = KeychainClientIdentityStore()
+) -> CertificateRotationScheduler {
+    let transport = EnrollmentTransportAdapter(http: http)
+    return CertificateRotationScheduler(
+        renewalState: { try store.renewalState() },
+        performRenew: {
+            guard let urlString = EnrollmentSettings.controlPlaneURL,
+                  let url = URL(string: urlString) else {
+                throw DeviceEnrollmentWiringError.missingControlPlaneURL
+            }
+            // nil bearer: /device/:id/renew authenticates by the presented
+            // client cert (mTLS), which the adapter's transport supplies.
+            let client = DeviceEnrollmentClient(baseURL: url, bearerToken: nil, transport: transport)
+            return try await store.renew(using: client)
+        }
+    )
+}
diff --git a/ios/App/WebTerm/Wiring/RootView.swift b/ios/App/WebTerm/Wiring/RootView.swift
index cd22681..a2f7255 100644
--- a/ios/App/WebTerm/Wiring/RootView.swift
+++ b/ios/App/WebTerm/Wiring/RootView.swift
@@ -75,9 +75,13 @@ struct StackRootView: View {
             viewModel: coordinator.sessionList,
             onOpen: { coordinator.open($0) },
             onAddHost: { coordinator.presentAddHost() },
-            onDeviceCert: { coordinator.presentDeviceCert() }
+            onDeviceCert: { coordinator.presentDeviceCert() },
+            onEnroll: { coordinator.presentEnrollment() }
         )
         .safeAreaInset(edge: .bottom) { continueLastBanner }
+        // B3 (HIGH) · A silently-failing device-cert renewal is surfaced here
+        // (top inset), so it is observable instead of buried in os.Logger.
+        .safeAreaInset(edge: .top) { certRenewalWarningBanner }
         // 横幅出现/消失走 DS 动效（reduceMotion 时塌成瞬切，无位移）。
         .animation(
             DS.Motion.gated(DS.Motion.base, reduceMotion: reduceMotion),
@@ -98,6 +102,15 @@ struct StackRootView: View {
         }
     }
 
+    // MARK: - Device-cert renewal warning (B3 HIGH observability fix)
+
+    @ViewBuilder private var certRenewalWarningBanner: some View {
+        if coordinator.isCertificateRenewalFailing {
+            CertRenewalWarningBanner()
+                .transition(.move(edge: .top).combined(with: .opacity))
+        }
+    }
+
     // MARK: - Terminal push
 
     private var terminalBinding: Binding<Bool> {
@@ -155,6 +168,32 @@ struct ContinueLastBanner: View {
     }
 }
 
+// MARK: - Device-cert renewal warning (B3 HIGH observability fix)
+
+/// A quiet, non-blocking warning that the silent device-certificate renewal is
+/// failing — surfaced from `AppCoordinator.isCertificateRenewalFailing` so a
+/// failing renewal is observable in the UI instead of only in os.Logger. Amber
+/// (the `waiting`/needs-me status color) + an SF Symbol so meaning is never
+/// carried by color alone. Non-interactive: the existing cert stays valid until
+/// expiry, and the next foreground retries automatically.
+struct CertRenewalWarningBanner: View {
+    var body: some View {
+        Label(RootCopy.certRenewalFailing, systemImage: "exclamationmark.shield")
+            .font(DS.Typography.caption)
+            .foregroundStyle(DS.Palette.statusWaiting)
+            .frame(maxWidth: .infinity, alignment: .leading)
+            .padding(.horizontal, DS.Space.lg16)
+            .padding(.vertical, DS.Space.sm8)
+            .background(.regularMaterial)
+            .overlay(alignment: .bottom) {
+                Rectangle()
+                    .fill(DS.Palette.hairline)
+                    .frame(height: DS.Stroke.hairline)
+            }
+            .accessibilityIdentifier("root.certRenewalWarning")
+    }
+}
+
 // MARK: - Projects toolbar item (shared stack + split, DRY)
 
 /// 「项目」leading 工具栏入口 —— stack 与 split 共用（同 disabled 条件、同
@@ -180,4 +219,6 @@ enum RootCopy {
     static let continueLast = "继续上次会话"
     static let projects = "项目"
     static let done = "完成"
+    /// B3 (HIGH) · Shown when the silent device-cert renewal keeps failing.
+    static let certRenewalFailing = "设备证书自动续期失败，将在下次前台重试"
 }
diff --git a/ios/App/WebTerm/Wiring/SplitRootView.swift b/ios/App/WebTerm/Wiring/SplitRootView.swift
index 97bb24d..362d8eb 100644
--- a/ios/App/WebTerm/Wiring/SplitRootView.swift
+++ b/ios/App/WebTerm/Wiring/SplitRootView.swift
@@ -40,7 +40,8 @@ struct SplitRootView: View {
                 coordinator.selectSidebarItem(sidebarItem(for: request))
             },
             onAddHost: { coordinator.presentAddHost() },
-            onDeviceCert: { coordinator.presentDeviceCert() }
+            onDeviceCert: { coordinator.presentDeviceCert() },
+            onEnroll: { coordinator.presentEnrollment() }
         )
         .safeAreaInset(edge: .bottom) { continueLastBanner }
         .animation(
diff --git a/ios/App/WebTermTests/EnrollmentViewModelTests.swift b/ios/App/WebTermTests/EnrollmentViewModelTests.swift
new file mode 100644
index 0000000..39aa85b
--- /dev/null
+++ b/ios/App/WebTermTests/EnrollmentViewModelTests.swift
@@ -0,0 +1,142 @@
+import ClientTLS
+import Foundation
+import Testing
+@testable import WebTerm
+
+/// B3 · EnrollmentViewModel — the zero-`.p12` enrollment flow's state machine.
+/// The enroll operation is injected as a closure (the flow logic itself is
+/// covered headlessly in ClientTLS's DeviceEnrollmentFlowTests); these cover the
+/// VM's boundary validation, success bookkeeping, and error→copy mapping —
+/// including that the password never lingers after an attempt.
+@MainActor
+@Suite("EnrollmentViewModel")
+struct EnrollmentViewModelTests {
+    /// Records enroll invocations + replays a scripted result/error.
+    private actor EnrollScript {
+        private(set) var calls: [(password: String, subdomain: String, deviceName: String, url: URL)] = []
+        private let result: Result<ClientCertificateSummary?, any Error>
+
+        init(result: Result<ClientCertificateSummary?, any Error>) {
+            self.result = result
+        }
+
+        func run(_ p: String, _ s: String, _ d: String, _ u: URL) throws -> ClientCertificateSummary? {
+            calls.append((p, s, d, u))
+            return try result.get()
+        }
+
+        var callCount: Int { calls.count }
+        var lastPassword: String? { calls.last?.password }
+    }
+
+    /// Records persisted settings so a test can assert them without real defaults.
+    private final class PersistSpy: @unchecked Sendable {
+        private let lock = NSLock()
+        private(set) var url: String?
+        private(set) var subdomain: String?
+        func persist(_ url: String, _ subdomain: String) {
+            lock.withLock { self.url = url; self.subdomain = subdomain }
+        }
+    }
+
+    private func makeVM(
+        script: EnrollScript,
+        persist: PersistSpy = PersistSpy(),
+        url: String = "https://cp.terminal.yaojia.wang",
+        subdomain: String = "alice",
+        summary: ClientCertificateSummary? = nil
+    ) -> EnrollmentViewModel {
+        EnrollmentViewModel(
+            controlPlaneURLText: url,
+            subdomain: subdomain,
+            deviceName: "Test iPhone",
+            enrollOperation: { p, s, d, u in try await script.run(p, s, d, u) },
+            loadSummary: { summary },
+            persistSettings: { persist.persist($0, $1) }
+        )
+    }
+
+    @Test("a successful enroll sets the summary, flags success, clears the password, persists settings")
+    func successPath() async {
+        let sum = ClientCertificateSummary(
+            subjectCommonName: "Test iPhone", issuerCommonName: "webterm-device-ca", notAfter: nil
+        )
+        let script = EnrollScript(result: .success(sum))
+        let persist = PersistSpy()
+        let vm = makeVM(script: script, persist: persist, summary: sum)
+        vm.password = "operator-secret"
+
+        await vm.enroll()
+
+        #expect(await script.callCount == 1)
+        #expect(vm.didSucceed == true)
+        #expect(vm.errorMessage == nil)
+        #expect(vm.password == "") // never lingers
+        #expect(vm.summary?.subjectCommonName == "Test iPhone")
+        #expect(persist.url == "https://cp.terminal.yaojia.wang")
+        #expect(persist.subdomain == "alice")
+    }
+
+    @Test("a non-https control-plane URL is rejected before any network")
+    func rejectsInsecureURL() async {
+        let script = EnrollScript(result: .success(nil))
+        let vm = makeVM(script: script, url: "http://cp.terminal.yaojia.wang")
+        vm.password = "pw"
+
+        await vm.enroll()
+
+        #expect(await script.callCount == 0) // zero network
+        #expect(vm.errorMessage == EnrollmentCopy.errInvalidURL)
+        #expect(vm.didSucceed == false)
+    }
+
+    @Test("a 403 subdomain-not-owned maps to actionable copy; password still cleared")
+    func mapsSubdomainNotOwned() async {
+        let script = EnrollScript(
+            result: .failure(DeviceEnrollmentError.http(status: 403, code: "rejected"))
+        )
+        let vm = makeVM(script: script)
+        vm.password = "operator-secret"
+
+        await vm.enroll()
+
+        #expect(vm.errorMessage == EnrollmentCopy.errSubdomainNotOwned)
+        #expect(vm.didSucceed == false)
+        #expect(vm.password == "") // cleared even on failure
+    }
+
+    @Test("a 401 login maps to the bad-credential copy")
+    func mapsBadCredential() async {
+        let script = EnrollScript(
+            result: .failure(ControlPlaneLoginError.http(status: 401, code: "login rejected"))
+        )
+        let vm = makeVM(script: script)
+        vm.password = "wrong"
+
+        await vm.enroll()
+        #expect(vm.errorMessage == EnrollmentCopy.errBadCredential)
+    }
+
+    @Test("Secure Enclave unavailable (simulator) maps to a clear message")
+    func mapsNoSecureEnclave() async {
+        let script = EnrollScript(
+            result: .failure(SecureEnclaveKeyError.secureEnclaveUnavailable("no entitlement"))
+        )
+        let vm = makeVM(script: script)
+        vm.password = "operator-secret"
+
+        await vm.enroll()
+        #expect(vm.errorMessage == EnrollmentCopy.errNoSecureEnclave)
+    }
+
+    @Test("canEnroll requires every field including a non-empty password")
+    func canEnrollGating() {
+        let script = EnrollScript(result: .success(nil))
+        let vm = makeVM(script: script)
+        #expect(vm.canEnroll == false) // password empty
+        vm.password = "pw"
+        #expect(vm.canEnroll == true)
+        vm.subdomain = "   "
+        #expect(vm.canEnroll == false) // whitespace-only subdomain
+    }
+}
diff --git a/ios/Packages/ClientTLS/Sources/ClientTLS/CertificateRotationScheduler.swift b/ios/Packages/ClientTLS/Sources/ClientTLS/CertificateRotationScheduler.swift
new file mode 100644
index 0000000..a4ee797
--- /dev/null
+++ b/ios/Packages/ClientTLS/Sources/ClientTLS/CertificateRotationScheduler.swift
@@ -0,0 +1,107 @@
+import Foundation
+import os
+
+/// B3 · Rotation timing of an installed enrolled (Secure-Enclave) identity. The
+/// scheduler reads this to decide whether to pre-empt expiry. The private key
+/// itself never leaves the Secure Enclave, so only advisory timing surfaces.
+public struct DeviceRenewalState: Equatable, Sendable {
+    /// The enrolled device id — drives `POST /device/:id/renew`.
+    public let deviceId: String
+    /// Leaf `notAfter` (hard expiry — the TLS stack rejects past it).
+    public let notAfter: Date?
+    /// When to renew from the same hardware key (~2/3 of the lifetime).
+    public let renewAfter: Date?
+
+    public init(deviceId: String, notAfter: Date?, renewAfter: Date?) {
+        self.deviceId = deviceId
+        self.notAfter = notAfter
+        self.renewAfter = renewAfter
+    }
+
+    /// Is the leaf due for renewal as of `now`? A missing `renewAfter` NEVER
+    /// triggers (fail-safe — the TLS stack is the real gate; the scheduler only
+    /// pre-empts expiry). Mirrors `EnrollmentResult.isRenewalDue`.
+    public func isRenewalDue(asOf now: Date) -> Bool {
+        guard let renewAfter else { return false }
+        return now >= renewAfter
+    }
+}
+
+/// B3 · The silent rotation scheduler: on a trigger (app foreground / launch) it
+/// checks the installed identity's rotation timing and, if the renew window has
+/// opened, drives an mTLS renew against the SAME Secure-Enclave key. This is the
+/// "one bootstrap tap, then never again" half of zero-touch — after the first
+/// login+enroll, the cert renews itself with no human action.
+///
+/// Deliberately pure and transport-free: `renewalState` and `performRenew` are
+/// injected closures, so the whole decision table is unit-testable with fakes
+/// (no keychain, no network). Production wires `renewalState` to the keychain
+/// store and `performRenew` to an mTLS `DeviceEnrollmentClient` renew (nil
+/// bearer — the current cert authenticates).
+///
+/// Failure posture: a keychain read fault or a renew error is surfaced as
+/// `.failed` and logged (never a secret), NEVER a crash — the existing cert
+/// stays valid until `notAfter`, so a transient renew failure is recoverable on
+/// the next trigger.
+public struct CertificateRotationScheduler: Sendable {
+    /// Current rotation timing; `nil` = nothing enrolled to renew.
+    private let renewalState: @Sendable () throws -> DeviceRenewalState?
+    /// The mTLS renew operation (re-CSR from the SE key → replace the leaf).
+    private let performRenew: @Sendable () async throws -> ClientCertificateSummary?
+    private let now: @Sendable () -> Date
+
+    public init(
+        renewalState: @escaping @Sendable () throws -> DeviceRenewalState?,
+        performRenew: @escaping @Sendable () async throws -> ClientCertificateSummary?,
+        now: @escaping @Sendable () -> Date = { Date() }
+    ) {
+        self.renewalState = renewalState
+        self.performRenew = performRenew
+        self.now = now
+    }
+
+    /// The outcome of a single scheduler pass — total over the decision table.
+    public enum Outcome: Equatable, Sendable {
+        /// No enrolled identity (fresh install / legacy `.p12`): nothing to do.
+        case notEnrolled
+        /// Enrolled but the renew window has not opened yet.
+        case notDue(renewAfter: Date?)
+        /// The renew succeeded; the new leaf is installed for the next handshake.
+        case renewed
+        /// A read/renew error occurred; logged, cert still valid until expiry.
+        case failed
+    }
+
+    /// Run one pass: read timing → decide → renew if due. Idempotent and safe to
+    /// call on every foreground; `.notDue` is the common (cheap) case.
+    public func runIfDue() async -> Outcome {
+        let state: DeviceRenewalState?
+        do {
+            state = try renewalState()
+        } catch {
+            RotationLog.log.error(
+                "rotation: renewal-state read failed: \(String(describing: error), privacy: .public)"
+            )
+            return .failed
+        }
+        guard let state else { return .notEnrolled }
+        guard state.isRenewalDue(asOf: now()) else {
+            return .notDue(renewAfter: state.renewAfter)
+        }
+        do {
+            _ = try await performRenew()
+            RotationLog.log.info("rotation: device certificate renewed silently")
+            return .renewed
+        } catch {
+            // No secrets in the log — only the error shape (never token/cert bytes).
+            RotationLog.log.error(
+                "rotation: silent renew failed: \(String(describing: error), privacy: .public)"
+            )
+            return .failed
+        }
+    }
+}
+
+private enum RotationLog {
+    static let log = Logger(subsystem: "com.yaojia.webterm", category: "cert-rotation")
+}
diff --git a/ios/Packages/ClientTLS/Sources/ClientTLS/ControlPlaneLoginClient.swift b/ios/Packages/ClientTLS/Sources/ClientTLS/ControlPlaneLoginClient.swift
new file mode 100644
index 0000000..afe4d9a
--- /dev/null
+++ b/ios/Packages/ClientTLS/Sources/ClientTLS/ControlPlaneLoginClient.swift
@@ -0,0 +1,108 @@
+import Foundation
+
+/// B3 · The phone-track bootstrap: exchanges the operator's one-time credential
+/// for a short-lived `device:enroll` bearer at the control-plane.
+///
+/// PINNED login contract (all pieces MUST agree — iOS / Android / server B1):
+///
+///   `POST /auth/login { "password": "<operator secret>" }`
+///     → 201 { "enrollToken": "<jwt/capability>", "accountId": "<uuid>", "expiresIn": <seconds> }
+///
+/// The returned `enrollToken` is then presented as `Authorization: Bearer …` to
+/// `DeviceEnrollmentClient.enroll`. This client is deliberately logic-free about
+/// TLS and reuses the SAME `EnrollmentTransport` seam as `DeviceEnrollmentClient`,
+/// so production injects `URLSessionHTTPTransport` and tests inject a stub.
+///
+/// Security posture:
+/// - The password is validated at the boundary (non-empty) and sent ONCE; it is
+///   never persisted, never logged, and no other field rides along in the body.
+/// - The `enrollToken` is a secret bearer: it is never logged here either. Only
+///   the transport (which sees it in a header) and the caller hold it, briefly.
+public struct ControlPlaneLoginClient: Sendable {
+    private let baseURL: URL
+    private let transport: any EnrollmentTransport
+
+    public init(baseURL: URL, transport: any EnrollmentTransport) {
+        self.baseURL = baseURL
+        self.transport = transport
+    }
+
+    /// Exchange the operator credential for a `device:enroll` bearer.
+    ///
+    /// - Throws: `ControlPlaneLoginError.emptyPassword` (before any network),
+    ///   `.http(status:code:)` on a non-201 (401 = bad/missing credential),
+    ///   `.malformedResponse` on a 201 body that does not decode.
+    public func login(password: String) async throws -> LoginResult {
+        // Boundary validation — fail fast, never send an empty credential.
+        guard !password.isEmpty else { throw ControlPlaneLoginError.emptyPassword }
+
+        guard let url = URL(string: "/auth/login", relativeTo: baseURL) else {
+            throw ControlPlaneLoginError.malformedResponse
+        }
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        // Password ONLY — no accountId / device fields leak from the client.
+        request.httpBody = try JSONSerialization.data(withJSONObject: ["password": password])
+
+        let (data, response) = try await transport.send(request)
+        guard response.statusCode == 201 else {
+            throw ControlPlaneLoginError.http(status: response.statusCode, code: errorCode(in: data))
+        }
+        guard let dto = try? JSONDecoder().decode(LoginResponseDTO.self, from: data) else {
+            throw ControlPlaneLoginError.malformedResponse
+        }
+        return dto.toResult()
+    }
+
+    private func errorCode(in data: Data) -> String? {
+        (try? JSONDecoder().decode(LoginErrorDTO.self, from: data))?.error
+    }
+}
+
+// MARK: - Result & errors
+
+/// The login exchange result. The `enrollToken` is a short-lived secret bearer;
+/// hold it only as long as needed to drive `DeviceEnrollmentClient.enroll`.
+public struct LoginResult: Equatable, Sendable {
+    /// The `device:enroll` capability bearer to present to `/device/enroll`.
+    public let enrollToken: String
+    /// The authenticated account (the token `sub`); the device enrolls under a
+    /// subdomain this account owns (server enforces ownership, deny-by-default).
+    public let accountId: String
+    /// Token lifetime in seconds (minutes-scale). Advisory: the enrollment must
+    /// complete within this window or the bearer is re-minted via another login.
+    public let expiresIn: Int
+
+    public init(enrollToken: String, accountId: String, expiresIn: Int) {
+        self.enrollToken = enrollToken
+        self.accountId = accountId
+        self.expiresIn = expiresIn
+    }
+}
+
+public enum ControlPlaneLoginError: Error, Equatable, Sendable {
+    /// The password was empty — rejected before any network call.
+    case emptyPassword
+    /// Non-success HTTP status with the server's uniform `{ error }` code, if any
+    /// (401 = bad/missing credential, 429 = rate_limited).
+    case http(status: Int, code: String?)
+    /// A 2xx body that did not decode to the expected shape.
+    case malformedResponse
+}
+
+// MARK: - Wire DTOs
+
+private struct LoginResponseDTO: Decodable {
+    let enrollToken: String
+    let accountId: String
+    let expiresIn: Int
+
+    func toResult() -> LoginResult {
+        LoginResult(enrollToken: enrollToken, accountId: accountId, expiresIn: expiresIn)
+    }
+}
+
+private struct LoginErrorDTO: Decodable {
+    let error: String
+}
diff --git a/ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentClient.swift b/ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentClient.swift
index a0f533c..c283900 100644
--- a/ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentClient.swift
+++ b/ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentClient.swift
@@ -16,11 +16,15 @@ import Foundation
 /// server's `decodeCsrWire` accepts directly.
 public struct DeviceEnrollmentClient: Sendable {
     private let baseURL: URL
-    /// The one-time account `device:enroll` bearer obtained at login.
-    private let bearerToken: String
+    /// The one-time account `device:enroll` bearer obtained at login. `nil` on
+    /// the renew path, which authenticates by the CURRENT device client cert
+    /// (mTLS) — the silent rotation scheduler has no fresh bearer weeks later, so
+    /// it constructs the client with `nil` and relies on the transport presenting
+    /// the installed identity. When `nil`, no `Authorization` header is sent.
+    private let bearerToken: String?
     private let transport: any EnrollmentTransport
 
-    public init(baseURL: URL, bearerToken: String, transport: any EnrollmentTransport) {
+    public init(baseURL: URL, bearerToken: String? = nil, transport: any EnrollmentTransport) {
         self.baseURL = baseURL
         self.bearerToken = bearerToken
         self.transport = transport
@@ -42,10 +46,12 @@ public struct DeviceEnrollmentClient: Sendable {
     }
 
     /// Renew against the SAME hardware key (A6 seam): a fresh CSR to
-    /// `/device/:id/renew`. Server support lands in A6; the client shape is here
-    /// so the rotation scheduler has an endpoint to drive.
+    /// `/device/:id/renew`. The endpoint authenticates by the presented mTLS cert
+    /// and its schema is strict — the body is `{ csr }` ONLY (NOT the enroll body).
+    /// A stray `keyAlg` (or any non-`csr` field) trips server validation and 400s
+    /// every silent renewal, so it is deliberately absent here.
     public func renew(deviceId: String, csrDER: Data) async throws -> EnrollmentResult {
-        let body = ["csr": csrDER.base64EncodedString(), "keyAlg": "ec-p256"]
+        let body = ["csr": csrDER.base64EncodedString()]
         let path = "/device/\(deviceId)/renew"
         let request = try makeJSONRequest(path: path, jsonObject: body)
         return try await sendExpectingLeaf(request)
@@ -73,7 +79,11 @@ public struct DeviceEnrollmentClient: Sendable {
         }
         var request = URLRequest(url: url)
         request.httpMethod = "POST"
-        request.setValue("Bearer \(bearerToken)", forHTTPHeaderField: "Authorization")
+        // Bearer only when present (enroll). The renew path passes nil and
+        // authenticates via the presented client certificate (mTLS).
+        if let bearerToken {
+            request.setValue("Bearer \(bearerToken)", forHTTPHeaderField: "Authorization")
+        }
         request.setValue("application/json", forHTTPHeaderField: "Content-Type")
         request.httpBody = try JSONSerialization.data(withJSONObject: jsonObject)
         return request
diff --git a/ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentFlow.swift b/ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentFlow.swift
new file mode 100644
index 0000000..fbcf706
--- /dev/null
+++ b/ios/Packages/ClientTLS/Sources/ClientTLS/DeviceEnrollmentFlow.swift
@@ -0,0 +1,63 @@
+import Foundation
+
+/// B3 · The phone-track enrollment FLOW — the composition that turns the pinned
+/// bootstrap contract into an installed, hardware-bound device identity:
+///
+///   1. `POST /auth/login { password }`  → short-lived `device:enroll` bearer.
+///   2. Build a `DeviceEnrollmentClient` authenticated with THAT bearer.
+///   3. `install` = generate a NON-EXPORTABLE Secure-Enclave key, self-sign a
+///      PKCS#10 CSR, `POST /device/enroll`, and store the returned leaf against
+///      the SE key — so it presents automatically on the existing mTLS path.
+///
+/// It reuses the enrollment library wholesale (`ControlPlaneLoginClient`,
+/// `DeviceEnrollmentClient`, `KeychainClientIdentityStore.enroll`) and adds NO
+/// crypto/keychain of its own — it is pure orchestration, so it is unit-testable
+/// with a stub transport + a fake installer (no network, no keychain).
+///
+/// The `install` step is injected (rather than a hard dependency on the keychain
+/// store) so the composition is testable off-device; production supplies the
+/// `KeychainClientIdentityStore` convenience initializer below.
+public struct DeviceEnrollmentFlow: Sendable {
+    /// The install step: given the bearer-authenticated client + the requested
+    /// subdomain/name, generate the SE key + CSR, enroll, and persist the leaf.
+    /// Returns the installed cert summary (nil only if the leaf can't be read).
+    public typealias Install = @Sendable (
+        _ client: DeviceEnrollmentClient, _ subdomain: String, _ deviceName: String
+    ) async throws -> ClientCertificateSummary?
+
+    private let baseURL: URL
+    private let transport: any EnrollmentTransport
+    private let install: Install
+
+    public init(baseURL: URL, transport: any EnrollmentTransport, install: @escaping Install) {
+        self.baseURL = baseURL
+        self.transport = transport
+        self.install = install
+    }
+
+    /// Production convenience: wire `install` to the keychain store's
+    /// Secure-Enclave enrollment (the `.p12`-free path). The SE key is generated
+    /// inside `store.enroll` and never leaves hardware.
+    public init(
+        baseURL: URL, transport: any EnrollmentTransport, store: KeychainClientIdentityStore
+    ) {
+        self.init(baseURL: baseURL, transport: transport) { client, subdomain, deviceName in
+            try await store.enroll(using: client, subdomain: subdomain, deviceName: deviceName)
+        }
+    }
+
+    /// Run the full bootstrap. Errors propagate unchanged so the UI can map them:
+    /// `ControlPlaneLoginError` (login step), `DeviceEnrollmentError` (enroll
+    /// step, e.g. 403 subdomain-not-owned), or a keychain/CSR error from install.
+    /// A login failure short-circuits — the enroll step never runs.
+    public func run(
+        password: String, subdomain: String, deviceName: String
+    ) async throws -> ClientCertificateSummary? {
+        let login = try await ControlPlaneLoginClient(baseURL: baseURL, transport: transport)
+            .login(password: password)
+        let client = DeviceEnrollmentClient(
+            baseURL: baseURL, bearerToken: login.enrollToken, transport: transport
+        )
+        return try await install(client, subdomain, deviceName)
+    }
+}
diff --git a/ios/Packages/ClientTLS/Sources/ClientTLS/KeychainClientIdentityStore.swift b/ios/Packages/ClientTLS/Sources/ClientTLS/KeychainClientIdentityStore.swift
index ab21fd6..ec0cb71 100644
--- a/ios/Packages/ClientTLS/Sources/ClientTLS/KeychainClientIdentityStore.swift
+++ b/ios/Packages/ClientTLS/Sources/ClientTLS/KeychainClientIdentityStore.swift
@@ -172,6 +172,20 @@ public struct KeychainClientIdentityStore: ClientIdentityStore {
         return try loadSummary()
     }
 
+    /// B3 · Rotation timing of the installed enrolled (Secure-Enclave) identity,
+    /// read for the silent rotation scheduler. `nil` when there is no enrolled
+    /// identity (a fresh install, or a legacy `.p12`-only device — neither of
+    /// which the scheduler can silently renew). The private key never leaves the
+    /// Secure Enclave, so only the advisory timing + deviceId surface here.
+    public func renewalState() throws -> DeviceRenewalState? {
+        guard let record = try readEnrollment() else { return nil }
+        return DeviceRenewalState(
+            deviceId: record.deviceId,
+            notAfter: record.notAfter,
+            renewAfter: record.renewAfter
+        )
+    }
+
     /// The Secure-Enclave-backed identity: the assembled `SecIdentity` (leaf bound
     /// to the SE key) plus the stored issuer chain. `nil` when not enrolled.
     func loadDeviceIdentity() throws -> ClientIdentity? {
@@ -205,31 +219,62 @@ public struct KeychainClientIdentityStore: ClientIdentityStore {
         return SecItemCopyMatching(query as CFDictionary, nil) == errSecSuccess
     }
 
-    /// Persist the enrolled leaf (delete-then-add so rotation replaces the prior
-    /// one) plus the enrollment record. The leaf binds to the permanent SE key,
-    /// letting the keychain form the identity on load.
+    /// Persist the enrolled leaf plus the enrollment record. The leaf binds to the
+    /// permanent SE key, letting the keychain form the identity on load.
+    ///
+    /// ATOMIC replace (reached automatically by the rotation scheduler): ADD the
+    /// new leaf BEFORE deleting the prior one — the inverse of delete-then-add,
+    /// whose window has zero leaves installed. An interrupted write therefore
+    /// never strands the device without an identity. The prior leaf is deleted by
+    /// its captured persistent ref (both share `leafLabel`, so a label-only delete
+    /// would also remove the just-added replacement).
     private func storeEnrolledLeaf(_ result: EnrollmentResult, deviceName: String) throws {
         guard let certificate = SecCertificateCreateWithData(nil, result.certificate as CFData)
         else {
             throw ClientIdentityStoreError.corruptStoredBlob // not a valid DER cert
         }
-        let deleteLeaf: [String: Any] = [
-            kSecClass as String: kSecClassCertificate,
-            kSecAttrLabel as String: leafLabel,
-        ]
-        let deleteStatus = SecItemDelete(deleteLeaf as CFDictionary)
-        guard deleteStatus == errSecSuccess || deleteStatus == errSecItemNotFound else {
-            throw ClientIdentityStoreError.keychain(deleteStatus)
-        }
-        let addLeaf: [String: Any] = [
-            kSecClass as String: kSecClassCertificate,
-            kSecValueRef as String: certificate,
-            kSecAttrLabel as String: leafLabel,
-        ]
-        let addStatus = SecItemAdd(addLeaf as CFDictionary, nil)
-        guard addStatus == errSecSuccess else {
-            throw ClientIdentityStoreError.keychain(addStatus)
-        }
+        // Capture the prior leaf BEFORE the add so it can be deleted by identity
+        // afterwards. `nil` on first enroll (nothing to replace).
+        let priorLeafRef = existingLeafPersistentRef()
+        var addedDistinctLeaf = false
+        try replaceKeychainItemAtomically(
+            addNew: {
+                let addLeaf: [String: Any] = [
+                    kSecClass as String: kSecClassCertificate,
+                    kSecValueRef as String: certificate,
+                    kSecAttrLabel as String: leafLabel,
+                ]
+                let addStatus = SecItemAdd(addLeaf as CFDictionary, nil)
+                switch addStatus {
+                case errSecSuccess:
+                    addedDistinctLeaf = true // a new, distinct leaf now coexists with the old
+                case errSecDuplicateItem:
+                    // Byte-identical re-store (same serial): the leaf is already
+                    // installed. Keep it and DO NOT delete the prior ref — it is
+                    // the very item we just tried to add.
+                    addedDistinctLeaf = false
+                default:
+                    throw ClientIdentityStoreError.keychain(addStatus)
+                }
+            },
+            deleteOld: {
+                // Only sweep the prior leaf once a distinct replacement is in place.
+                guard addedDistinctLeaf, let priorLeafRef else { return }
+                let deleteStatus = SecItemDelete(
+                    [kSecValuePersistentRef as String: priorLeafRef] as CFDictionary
+                )
+                guard deleteStatus == errSecSuccess || deleteStatus == errSecItemNotFound else {
+                    throw ClientIdentityStoreError.keychain(deleteStatus)
+                }
+            },
+            reportStaleDeleteFailure: { error in
+                // Non-fatal: the new leaf is installed (renewal succeeded). A stale
+                // leftover binds to the same SE key and is swept on the next write.
+                ClientTLSLog.identity.error(
+                    "storeEnrolledLeaf: stale leaf delete failed (new leaf installed): \(String(describing: error), privacy: .public)"
+                )
+            }
+        )
         try writeEnrollment(
             StoredEnrollment(
                 deviceId: result.deviceId,
@@ -241,6 +286,22 @@ public struct KeychainClientIdentityStore: ClientIdentityStore {
         )
     }
 
+    /// Persistent reference of the currently-installed enrolled leaf (by label),
+    /// captured before an atomic replace so the prior copy can be deleted by
+    /// identity. `nil` when none is installed or the lookup fails (first enroll).
+    private func existingLeafPersistentRef() -> Data? {
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassCertificate,
+            kSecAttrLabel as String: leafLabel,
+            kSecReturnPersistentRef as String: true,
+            kSecMatchLimit as String: kSecMatchLimitOne,
+        ]
+        var result: CFTypeRef?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+        guard status == errSecSuccess, let data = result as? Data else { return nil }
+        return data
+    }
+
     /// Delete the SE key, the enrolled leaf, and the enrollment record. Idempotent.
     private func removeEnrolled() throws {
         let deleteLeaf: [String: Any] = [
@@ -273,9 +334,17 @@ public struct KeychainClientIdentityStore: ClientIdentityStore {
         } catch {
             throw ClientIdentityStoreError.corruptStoredBlob
         }
-        let deleteStatus = SecItemDelete(enrollmentQuery() as CFDictionary)
-        guard deleteStatus == errSecSuccess || deleteStatus == errSecItemNotFound else {
-            throw ClientIdentityStoreError.keychain(deleteStatus)
+        // ATOMIC upsert (reached automatically by the rotation scheduler): update
+        // the DATA in place — the (service, account) primary key and protection
+        // class are unchanged on renewal, so no delete-then-add window can strand
+        // the device without its enrollment record. Fall back to add on first write.
+        let updateStatus = SecItemUpdate(
+            enrollmentQuery() as CFDictionary,
+            [kSecValueData as String: data] as CFDictionary
+        )
+        if updateStatus == errSecSuccess { return }
+        guard updateStatus == errSecItemNotFound else {
+            throw ClientIdentityStoreError.keychain(updateStatus)
         }
         var attributes = enrollmentQuery()
         attributes[kSecValueData as String] = data
diff --git a/ios/Packages/ClientTLS/Sources/ClientTLS/KeychainItemReplace.swift b/ios/Packages/ClientTLS/Sources/ClientTLS/KeychainItemReplace.swift
new file mode 100644
index 0000000..dbed93c
--- /dev/null
+++ b/ios/Packages/ClientTLS/Sources/ClientTLS/KeychainItemReplace.swift
@@ -0,0 +1,30 @@
+import Foundation
+
+/// Replace a keychain-backed item so a crash/failure mid-write can NEVER leave
+/// zero installed copies — which, for the device identity, would lock the device
+/// out of its own mTLS cert until a manual re-enroll. This is the inverse of a
+/// delete-then-add sequence, whose window between the two calls has zero items:
+///
+///   1. `addNew` FIRST. Once it succeeds the replacement is installed, so at
+///      least one valid item exists from here on. If `addNew` throws, the prior
+///      item is left untouched (the device keeps a working identity) and the
+///      error propagates.
+///   2. `deleteOld` SECOND, removing the prior copy. A failure here is NON-fatal:
+///      the new item is already installed, so the write is a success. The stale
+///      leftover is reported via `reportStaleDeleteFailure` (never a lockout) and
+///      swept on the next write — throwing here would strand a working new cert.
+///
+/// Kept pure (closures, no `Security` types) so the ordering invariant is unit-
+/// testable with fakes; the keychain plumbing lives at the call sites.
+func replaceKeychainItemAtomically(
+    addNew: () throws -> Void,
+    deleteOld: () throws -> Void,
+    reportStaleDeleteFailure: (Error) -> Void = { _ in }
+) throws {
+    try addNew()
+    do {
+        try deleteOld()
+    } catch {
+        reportStaleDeleteFailure(error)
+    }
+}
diff --git a/ios/Packages/ClientTLS/Tests/ClientTLSTests/CertificateRotationSchedulerTests.swift b/ios/Packages/ClientTLS/Tests/ClientTLSTests/CertificateRotationSchedulerTests.swift
new file mode 100644
index 0000000..af58086
--- /dev/null
+++ b/ios/Packages/ClientTLS/Tests/ClientTLSTests/CertificateRotationSchedulerTests.swift
@@ -0,0 +1,107 @@
+import Foundation
+import Testing
+@testable import ClientTLS
+
+// B3 · The silent rotation scheduler decides — from the installed identity's
+// rotation timing — whether to renew before expiry, then drives an injected
+// mTLS renew. Pure and transport-free: fully unit-testable with fakes.
+
+private let t0 = ISO8601DateFormatter().date(from: "2026-09-05T00:00:00Z")!
+private let renewAfter = ISO8601DateFormatter().date(from: "2026-09-05T00:00:00Z")!
+private let notAfter = ISO8601DateFormatter().date(from: "2026-10-06T00:00:00Z")!
+private let before = ISO8601DateFormatter().date(from: "2026-09-04T00:00:00Z")!
+private let after = ISO8601DateFormatter().date(from: "2026-09-06T00:00:00Z")!
+
+private func state(renewAfter: Date? = renewAfter) -> DeviceRenewalState {
+    DeviceRenewalState(deviceId: "dev-1", notAfter: notAfter, renewAfter: renewAfter)
+}
+
+/// Records how many times the renew operation ran. `@unchecked Sendable`: guarded
+/// by a lock.
+private final class RenewSpy: @unchecked Sendable {
+    private let lock = NSLock()
+    private var _count = 0
+    var count: Int { lock.withLock { _count } }
+    func bump() { lock.withLock { _count += 1 } }
+}
+
+@Test("no enrolled identity → notEnrolled, and renew never runs")
+func schedulerNotEnrolled() async {
+    let spy = RenewSpy()
+    let scheduler = CertificateRotationScheduler(
+        renewalState: { nil },
+        performRenew: { spy.bump(); return nil },
+        now: { after }
+    )
+    let outcome = await scheduler.runIfDue()
+    #expect(outcome == .notEnrolled)
+    #expect(spy.count == 0)
+}
+
+@Test("cert not yet due → notDue, and renew never runs")
+func schedulerNotDue() async {
+    let spy = RenewSpy()
+    let scheduler = CertificateRotationScheduler(
+        renewalState: { state() },
+        performRenew: { spy.bump(); return nil },
+        now: { before }
+    )
+    let outcome = await scheduler.runIfDue()
+    #expect(outcome == .notDue(renewAfter: renewAfter))
+    #expect(spy.count == 0)
+}
+
+@Test("past renewAfter → renews exactly once")
+func schedulerRenews() async {
+    let spy = RenewSpy()
+    let scheduler = CertificateRotationScheduler(
+        renewalState: { state() },
+        performRenew: { spy.bump(); return nil },
+        now: { after }
+    )
+    let outcome = await scheduler.runIfDue()
+    #expect(outcome == .renewed)
+    #expect(spy.count == 1)
+}
+
+@Test("due exactly at renewAfter (>= boundary) renews")
+func schedulerRenewsAtBoundary() async {
+    let scheduler = CertificateRotationScheduler(
+        renewalState: { state() },
+        performRenew: { nil },
+        now: { renewAfter } // now == renewAfter
+    )
+    #expect(await scheduler.runIfDue() == .renewed)
+}
+
+@Test("a missing renewAfter never triggers (fail-safe — TLS stack is the gate)")
+func schedulerMissingRenewAfterNeverDue() async {
+    let scheduler = CertificateRotationScheduler(
+        renewalState: { state(renewAfter: nil) },
+        performRenew: { nil },
+        now: { after }
+    )
+    #expect(await scheduler.runIfDue() == .notDue(renewAfter: nil))
+}
+
+@Test("a renew that throws is surfaced as .failed (never crashes, cert still valid)")
+func schedulerRenewFailure() async {
+    struct Boom: Error {}
+    let scheduler = CertificateRotationScheduler(
+        renewalState: { state() },
+        performRenew: { throw Boom() },
+        now: { after }
+    )
+    #expect(await scheduler.runIfDue() == .failed)
+}
+
+@Test("a keychain read fault is surfaced as .failed, not a crash")
+func schedulerReadFailure() async {
+    struct Boom: Error {}
+    let scheduler = CertificateRotationScheduler(
+        renewalState: { throw Boom() },
+        performRenew: { nil },
+        now: { after }
+    )
+    #expect(await scheduler.runIfDue() == .failed)
+}
diff --git a/ios/Packages/ClientTLS/Tests/ClientTLSTests/ControlPlaneLoginClientTests.swift b/ios/Packages/ClientTLS/Tests/ClientTLSTests/ControlPlaneLoginClientTests.swift
new file mode 100644
index 0000000..febabad
--- /dev/null
+++ b/ios/Packages/ClientTLS/Tests/ClientTLSTests/ControlPlaneLoginClientTests.swift
@@ -0,0 +1,123 @@
+import Foundation
+import Testing
+@testable import ClientTLS
+
+// B3 · ControlPlaneLoginClient request-building + response-mapping, driven by a
+// stub transport (no network). Mirrors the PINNED login contract exactly:
+//
+//   POST /auth/login { "password": "<operator secret>" }
+//     → 201 { "enrollToken": "<jwt/capability>", "accountId": "<uuid>", "expiresIn": <seconds> }
+
+private let cpBaseURL = URL(string: "https://cp.terminal.yaojia.wang")!
+
+/// Records the last request and replays a canned response. `@unchecked Sendable`:
+/// the mutable capture is guarded by a lock.
+private final class LoginStubTransport: EnrollmentTransport, @unchecked Sendable {
+    private let lock = NSLock()
+    private var _lastRequest: URLRequest?
+    private let status: Int
+    private let body: Data
+
+    init(status: Int, body: Data) {
+        self.status = status
+        self.body = body
+    }
+
+    var lastRequest: URLRequest? { lock.withLock { _lastRequest } }
+
+    func send(_ request: URLRequest) async throws -> (Data, HTTPURLResponse) {
+        lock.withLock { _lastRequest = request }
+        let response = HTTPURLResponse(
+            url: request.url!, statusCode: status, httpVersion: "HTTP/1.1", headerFields: nil
+        )!
+        return (body, response)
+    }
+}
+
+private func loginBody(
+    enrollToken: String = "v4.public.enroll-token",
+    accountId: String = "11111111-2222-3333-4444-555555555555",
+    expiresIn: Int = 600
+) -> Data {
+    let json: [String: Any] = [
+        "enrollToken": enrollToken,
+        "accountId": accountId,
+        "expiresIn": expiresIn,
+    ]
+    return try! JSONSerialization.data(withJSONObject: json)
+}
+
+@Test("login builds a POST /auth/login carrying only the password (never bearer)")
+func loginBuildsRequest() async throws {
+    // Arrange
+    let stub = LoginStubTransport(status: 201, body: loginBody())
+    let client = ControlPlaneLoginClient(baseURL: cpBaseURL, transport: stub)
+
+    // Act
+    _ = try await client.login(password: "operator-secret")
+
+    // Assert
+    let request = try #require(stub.lastRequest)
+    #expect(request.httpMethod == "POST")
+    #expect(request.url?.absoluteString == "https://cp.terminal.yaojia.wang/auth/login")
+    #expect(request.value(forHTTPHeaderField: "Content-Type") == "application/json")
+    // Login is credential-based, NOT bearer-authed — no Authorization header.
+    #expect(request.value(forHTTPHeaderField: "Authorization") == nil)
+
+    let sent = try #require(request.httpBody)
+    let object = try #require(try JSONSerialization.jsonObject(with: sent) as? [String: Any])
+    #expect(object["password"] as? String == "operator-secret")
+    #expect(object.keys.count == 1) // password ONLY — no extra fields leak
+}
+
+@Test("login maps a 201 response into a typed LoginResult")
+func loginMapsResponse() async throws {
+    // Arrange
+    let stub = LoginStubTransport(status: 201, body: loginBody(
+        enrollToken: "v4.public.abc", accountId: "acct-uuid", expiresIn: 900
+    ))
+    let client = ControlPlaneLoginClient(baseURL: cpBaseURL, transport: stub)
+
+    // Act
+    let result = try await client.login(password: "pw")
+
+    // Assert
+    #expect(result.enrollToken == "v4.public.abc")
+    #expect(result.accountId == "acct-uuid")
+    #expect(result.expiresIn == 900)
+}
+
+@Test("an empty password fails fast without any network call")
+func loginEmptyPasswordRejected() async throws {
+    // Arrange
+    let stub = LoginStubTransport(status: 201, body: loginBody())
+    let client = ControlPlaneLoginClient(baseURL: cpBaseURL, transport: stub)
+
+    // Act / Assert — boundary validation: reject before sending.
+    await #expect(throws: ControlPlaneLoginError.emptyPassword) {
+        _ = try await client.login(password: "")
+    }
+    #expect(stub.lastRequest == nil) // proves zero network happened
+}
+
+@Test("a 401 login response surfaces http with the server error code")
+func loginRejectSurfacesStatus() async throws {
+    // The login stub seam denies-by-default → { error: "login rejected" }.
+    let body = try! JSONSerialization.data(withJSONObject: ["error": "login rejected"])
+    let stub = LoginStubTransport(status: 401, body: body)
+    let client = ControlPlaneLoginClient(baseURL: cpBaseURL, transport: stub)
+
+    await #expect(throws: ControlPlaneLoginError.http(status: 401, code: "login rejected")) {
+        _ = try await client.login(password: "wrong")
+    }
+}
+
+@Test("a malformed 201 body throws malformedResponse")
+func loginMalformedBody() async throws {
+    let stub = LoginStubTransport(status: 201, body: Data("not json".utf8))
+    let client = ControlPlaneLoginClient(baseURL: cpBaseURL, transport: stub)
+
+    await #expect(throws: ControlPlaneLoginError.malformedResponse) {
+        _ = try await client.login(password: "pw")
+    }
+}
diff --git a/ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentClientTests.swift b/ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentClientTests.swift
index f2f1426..fb23287 100644
--- a/ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentClientTests.swift
+++ b/ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentClientTests.swift
@@ -169,3 +169,46 @@ func renewTargetsRenewEndpoint() async throws {
     #expect(stub.lastRequest?.url?.absoluteString
         == "https://cp.terminal.yaojia.wang/device/dev-9/renew")
 }
+
+@Test("renew body is {csr}-ONLY (server's strict schema rejects any extra field)")
+func renewSendsCsrOnlyBody() async throws {
+    // The control-plane /device/:id/renew schema authenticates by the presented
+    // mTLS cert and accepts a body of exactly { csr } — a stray `keyAlg` (or any
+    // non-csr field) trips its strict validation and 400s every silent renewal.
+    let stub = StubTransport(status: 201, body: enrollBody())
+    let client = DeviceEnrollmentClient(baseURL: baseURL, transport: stub)
+    let csr = Data([0x0A, 0x0B, 0x0C])
+
+    _ = try await client.renew(deviceId: "dev-9", csrDER: csr)
+
+    let request = try #require(stub.lastRequest)
+    let sent = try #require(request.httpBody)
+    let object = try #require(try JSONSerialization.jsonObject(with: sent) as? [String: Any])
+    #expect(object["csr"] as? String == csr.base64EncodedString())
+    #expect(object["keyAlg"] == nil) // NOT sent — the enroll-only field must be dropped
+    #expect(object.keys.sorted() == ["csr"]) // exactly one field
+}
+
+@Test("renew with no bearer sends NO Authorization header (mTLS-authenticated)")
+func renewMTLSOmitsBearer() async throws {
+    // /device/:id/renew authenticates by the CURRENT device client cert (mTLS),
+    // NOT a bearer — the silent rotation scheduler has no fresh bearer weeks
+    // later, so it constructs the client with a nil bearer and relies on the
+    // transport presenting the installed identity. The Authorization header
+    // must therefore be ABSENT (a stale/empty "Bearer " would be wrong).
+    let stub = StubTransport(status: 201, body: enrollBody())
+    let client = DeviceEnrollmentClient(baseURL: baseURL, transport: stub) // bearer defaults to nil
+    _ = try await client.renew(deviceId: "dev-9", csrDER: Data([0x02]))
+    let request = try #require(stub.lastRequest)
+    #expect(request.value(forHTTPHeaderField: "Authorization") == nil)
+    // Content-Type is still set — it's a JSON POST regardless of auth mechanism.
+    #expect(request.value(forHTTPHeaderField: "Content-Type") == "application/json")
+}
+
+@Test("enroll still sets the bearer when one is supplied (unchanged contract)")
+func enrollKeepsBearerWhenSupplied() async throws {
+    let stub = StubTransport(status: 201, body: enrollBody())
+    let client = DeviceEnrollmentClient(baseURL: baseURL, bearerToken: bearer, transport: stub)
+    _ = try await client.enroll(csrDER: Data([0x01]), subdomain: "a", deviceName: "d")
+    #expect(stub.lastRequest?.value(forHTTPHeaderField: "Authorization") == "Bearer \(bearer)")
+}
diff --git a/ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentFlowTests.swift b/ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentFlowTests.swift
new file mode 100644
index 0000000..7a0bd31
--- /dev/null
+++ b/ios/Packages/ClientTLS/Tests/ClientTLSTests/DeviceEnrollmentFlowTests.swift
@@ -0,0 +1,136 @@
+import Foundation
+import Testing
+@testable import ClientTLS
+
+// B3 · DeviceEnrollmentFlow composes the pinned bootstrap end-to-end:
+//   login(password) → bearer  →  enroll(CSR, subdomain) with that bearer  → leaf.
+// Driven by a path-routing stub transport (no network, no keychain): asserts the
+// bearer minted at login is exactly what authenticates the enroll call.
+
+private let flowBaseURL = URL(string: "https://cp.terminal.yaojia.wang")!
+
+/// Routes by path: `/auth/login` → login body, `/device/enroll` → enroll body.
+/// Records every request so the test can assert the enroll bearer. `@unchecked
+/// Sendable`: mutable captures guarded by a lock.
+private final class RoutingStubTransport: EnrollmentTransport, @unchecked Sendable {
+    private let lock = NSLock()
+    private var _requests: [URLRequest] = []
+    private let loginStatus: Int
+    private let loginBody: Data
+
+    init(loginStatus: Int = 201, loginBody: Data) {
+        self.loginStatus = loginStatus
+        self.loginBody = loginBody
+    }
+
+    var requests: [URLRequest] { lock.withLock { _requests } }
+    func request(forPathSuffix suffix: String) -> URLRequest? {
+        lock.withLock { _requests.first { $0.url?.path.hasSuffix(suffix) == true } }
+    }
+
+    func send(_ request: URLRequest) async throws -> (Data, HTTPURLResponse) {
+        lock.withLock { _requests.append(request) }
+        let path = request.url?.path ?? ""
+        let (status, body): (Int, Data)
+        if path.hasSuffix("/auth/login") {
+            (status, body) = (loginStatus, loginBody)
+        } else {
+            // /device/enroll → a minimal 201 leaf.
+            (status, body) = (201, enrollLeafBody())
+        }
+        let response = HTTPURLResponse(
+            url: request.url!, statusCode: status, httpVersion: "HTTP/1.1", headerFields: nil
+        )!
+        return (body, response)
+    }
+}
+
+private func loginResponseBody(enrollToken: String) -> Data {
+    try! JSONSerialization.data(withJSONObject: [
+        "enrollToken": enrollToken,
+        "accountId": "acct-123",
+        "expiresIn": 600,
+    ])
+}
+
+private func enrollLeafBody() -> Data {
+    try! JSONSerialization.data(withJSONObject: [
+        "deviceId": "dev-1",
+        "cert": Data([0x30, 0x01]).base64EncodedString(),
+        "caChain": [Data([0x30, 0x02]).base64EncodedString()],
+        "notBefore": "2026-07-18T00:00:00Z",
+        "notAfter": "2026-10-16T00:00:00Z",
+        "renewAfter": "2026-09-15T00:00:00Z",
+    ])
+}
+
+/// A fake installer that invokes the real `client.enroll` (so the transport sees
+/// the enroll request with the login-minted bearer), then returns a summary.
+/// Records the subdomain/deviceName it was handed. `@unchecked Sendable`: lock.
+private final class SpyInstaller: @unchecked Sendable {
+    private let lock = NSLock()
+    private(set) var subdomain: String?
+    private(set) var deviceName: String?
+
+    func install(
+        _ client: DeviceEnrollmentClient, _ subdomain: String, _ deviceName: String
+    ) async throws -> ClientCertificateSummary? {
+        lock.withLock { self.subdomain = subdomain; self.deviceName = deviceName }
+        _ = try await client.enroll(csrDER: Data([0xAB]), subdomain: subdomain, deviceName: deviceName)
+        return ClientCertificateSummary(
+            subjectCommonName: deviceName, issuerCommonName: "webterm-device-ca", notAfter: nil
+        )
+    }
+}
+
+@Test("flow logs in then enrolls with the login-minted bearer (end to end)")
+func flowEndToEnd() async throws {
+    // Arrange
+    let transport = RoutingStubTransport(loginBody: loginResponseBody(enrollToken: "TOKEN-XYZ"))
+    let installer = SpyInstaller()
+    let flow = DeviceEnrollmentFlow(
+        baseURL: flowBaseURL,
+        transport: transport,
+        install: installer.install
+    )
+
+    // Act
+    let summary = try await flow.run(password: "pw", subdomain: "alice", deviceName: "Alice iPhone")
+
+    // Assert — login happened, THEN enroll with the exact bearer from login.
+    #expect(transport.request(forPathSuffix: "/auth/login") != nil)
+    let enroll = try #require(transport.request(forPathSuffix: "/device/enroll"))
+    #expect(enroll.value(forHTTPHeaderField: "Authorization") == "Bearer TOKEN-XYZ")
+    #expect(installer.subdomain == "alice")
+    #expect(installer.deviceName == "Alice iPhone")
+    #expect(summary?.subjectCommonName == "Alice iPhone")
+}
+
+@Test("a login failure short-circuits: enroll is never attempted")
+func flowLoginFailureShortCircuits() async {
+    // 401 login → the flow must NOT reach /device/enroll.
+    let body = try! JSONSerialization.data(withJSONObject: ["error": "login rejected"])
+    let transport = RoutingStubTransport(loginStatus: 401, loginBody: body)
+    let installer = SpyInstaller()
+    let flow = DeviceEnrollmentFlow(
+        baseURL: flowBaseURL, transport: transport, install: installer.install
+    )
+
+    await #expect(throws: ControlPlaneLoginError.http(status: 401, code: "login rejected")) {
+        _ = try await flow.run(password: "wrong", subdomain: "alice", deviceName: "d")
+    }
+    #expect(transport.request(forPathSuffix: "/device/enroll") == nil)
+    #expect(installer.subdomain == nil) // installer never ran
+}
+
+@Test("an empty password is rejected before any network")
+func flowEmptyPassword() async {
+    let transport = RoutingStubTransport(loginBody: loginResponseBody(enrollToken: "t"))
+    let flow = DeviceEnrollmentFlow(
+        baseURL: flowBaseURL, transport: transport, install: { _, _, _ in nil }
+    )
+    await #expect(throws: ControlPlaneLoginError.emptyPassword) {
+        _ = try await flow.run(password: "", subdomain: "alice", deviceName: "d")
+    }
+    #expect(transport.requests.isEmpty)
+}
diff --git a/ios/Packages/ClientTLS/Tests/ClientTLSTests/KeychainItemReplaceTests.swift b/ios/Packages/ClientTLS/Tests/ClientTLSTests/KeychainItemReplaceTests.swift
new file mode 100644
index 0000000..300186e
--- /dev/null
+++ b/ios/Packages/ClientTLS/Tests/ClientTLSTests/KeychainItemReplaceTests.swift
@@ -0,0 +1,76 @@
+import Foundation
+import Testing
+@testable import ClientTLS
+
+// C-iOS · The keychain-replace helper backs the rotation scheduler's identity
+// updates. Its one job: a crash/failure mid-write must NEVER leave zero installed
+// items (which would lock the device out of its own mTLS identity until a manual
+// re-enroll). It enforces ADD-new-BEFORE-DELETE-old ordering — the inverse of the
+// delete-then-add sequence whose window has zero items installed.
+
+/// A tiny in-memory stand-in for the keychain: the current set of installed item
+/// ids plus the smallest count ever observed, so a test can assert the invariant
+/// that the installed set is NEVER empty at any step of the replace.
+private final class FakeKeychain {
+    private(set) var items: Set<String>
+    private(set) var log: [String] = []
+    private(set) var minCount: Int
+    init(seed: Set<String>) {
+        items = seed
+        minCount = seed.count
+    }
+
+    func add(_ id: String) {
+        items.insert(id)
+        log.append("add(\(id))")
+        minCount = min(minCount, items.count)
+    }
+
+    func delete(_ id: String) {
+        items.remove(id)
+        log.append("delete(\(id))")
+        minCount = min(minCount, items.count)
+    }
+}
+
+@Test("replace ADDS the new item before DELETING the old — never a zero-item window")
+func replaceAddsBeforeDeletes() throws {
+    let keychain = FakeKeychain(seed: ["old"])
+    try replaceKeychainItemAtomically(
+        addNew: { keychain.add("new") },
+        deleteOld: { keychain.delete("old") }
+    )
+    #expect(keychain.items == ["new"])
+    #expect(keychain.log == ["add(new)", "delete(old)"]) // add strictly precedes delete
+    #expect(keychain.minCount >= 1) // at least one identity installed at every step
+}
+
+@Test("a failed add leaves the prior item intact and never runs the delete")
+func replaceAddFailureKeepsOld() {
+    struct Boom: Error {}
+    let keychain = FakeKeychain(seed: ["old"])
+    #expect(throws: Boom.self) {
+        try replaceKeychainItemAtomically(
+            addNew: { throw Boom() },
+            deleteOld: { keychain.delete("old") }
+        )
+    }
+    #expect(keychain.items == ["old"]) // old preserved — a working identity remains
+    #expect(keychain.log.contains("delete(old)") == false)
+    #expect(keychain.minCount >= 1)
+}
+
+@Test("a failed delete-of-old is non-fatal — the new item stays installed and the fault is surfaced")
+func replaceDeleteFailureKeepsNew() throws {
+    struct Boom: Error {}
+    let keychain = FakeKeychain(seed: ["old"])
+    var reported: Error?
+    try replaceKeychainItemAtomically(
+        addNew: { keychain.add("new") },
+        deleteOld: { throw Boom() },
+        reportStaleDeleteFailure: { reported = $0 }
+    )
+    #expect(keychain.items.contains("new")) // renewal succeeded despite the stale-delete fault
+    #expect(reported is Boom) // surfaced (not silently swallowed)
+    #expect(keychain.minCount >= 1)
+}