Merge pull request #2 from loki-project/niels

Implement Mnemonic Based Key Pair Restoration

Signal/src/Signal-Bridging-Header.h

@@ -77,6 +77,7 @@
 #import <SignalServiceKit/Contact.h>
 #import <SignalServiceKit/ContactsUpdater.h>
 #import <SignalServiceKit/DataSource.h>
+#import <SignalServiceKit/ECKeyPair.h>
 #import <SignalServiceKit/MIMETypeUtil.h>
 #import <SignalServiceKit/NSData+Image.h>
 #import <SignalServiceKit/NSNotificationCenter+OWS.h>

Signal/src/ViewControllers/Registration/OnboardingKeyPairViewController.swift

@@ -1,9 +1,24 @@
 
 final class OnboardingKeyPairViewController : OnboardingBaseViewController {
+    private var mode: Mode = .register { didSet { if mode != oldValue { handleModeChanged() } } }
     private var keyPair: ECKeyPair! { didSet { updateMnemonic() } }
-    private var mnemonic: String! { didSet { mnemonicLabel.text = mnemonic } }
+    private var mnemonic: String! { didSet { handleMnemonicChanged() } }
     private var userName: String?
     
+    // MARK: Components
+    private lazy var registerStackView: UIStackView = {
+        let result = UIStackView(arrangedSubviews: [ explanationLabel, UIView.spacer(withHeight: 32), mnemonicLabel, UIView.spacer(withHeight: 24), copyButton, UIView.spacer(withHeight: 8), restoreButton ])
+        result.accessibilityIdentifier = "onboarding.keyPairStep.registerStackView"
+        result.axis = .vertical
+        return result
+    }()
+    
+    private lazy var explanationLabel: UILabel = {
+        let result = createExplanationLabel(text: NSLocalizedString("Please save the seed below in a safe location. It can be used to restore your account if you lose access, or to migrate to a new device.", comment: ""))
+        result.accessibilityIdentifier = "onboarding.keyPairStep.explanationLabel"
+        return result
+    }()
+    
     private lazy var mnemonicLabel: UILabel = {
         let result = createExplanationLabel(text: "")
         result.accessibilityIdentifier = "onboarding.keyPairStep.mnemonicLabel"
@@ -20,6 +35,43 @@ final class OnboardingKeyPairViewController : OnboardingBaseViewController {
         return result
     }()
     
+    private lazy var restoreButton: OWSFlatButton = {
+        let result = createLinkButton(title: NSLocalizedString("Restore Using Mnemonic", comment: ""), selector: #selector(switchMode))
+        result.accessibilityIdentifier = "onboarding.keyPairStep.restoreButton"
+        return result
+    }()
+    
+    private lazy var restoreStackView: UIStackView = {
+        let result = UIStackView(arrangedSubviews: [ mnemonicTextField, UIView.spacer(withHeight: 24), registerButton ])
+        result.accessibilityIdentifier = "onboarding.keyPairStep.restoreStackView"
+        result.axis = .vertical
+        return result
+    }()
+    
+    private lazy var mnemonicTextField: UITextField = {
+        let result = UITextField(frame: CGRect.zero)
+        result.accessibilityIdentifier = "onboarding.keyPairStep.mnemonicTextField"
+        result.textAlignment = .center
+        result.placeholder = NSLocalizedString("Enter Your Mnemonic", comment: "")
+        return result
+    }()
+    
+    private lazy var registerButton: OWSFlatButton = {
+        let result = createLinkButton(title: NSLocalizedString("Register a New Account", comment: ""), selector: #selector(switchMode))
+        result.accessibilityIdentifier = "onboarding.keyPairStep.registerButton"
+        return result
+    }()
+    
+    private lazy var registerOrRestoreButton: OWSFlatButton = {
+        let result = createButton(title: "", selector: #selector(registerOrRestore))
+        result.accessibilityIdentifier = "onboarding.keyPairStep.registerOrRestoreButton"
+        return result
+    }()
+    
+    // MARK: Types
+    enum Mode { case register, restore }
+    
+    // MARK: Lifecycle
     init(onboardingController: OnboardingController, userName: String?) {
         super.init(onboardingController: onboardingController)
         self.userName = userName
@@ -28,6 +80,7 @@ final class OnboardingKeyPairViewController : OnboardingBaseViewController {
     override public func viewDidLoad() {
         super.loadView()
         setUpViewHierarchy()
+        handleModeChanged() // Perform initial update
         updateKeyPair()
         // Test
         // ================
@@ -43,36 +96,50 @@ final class OnboardingKeyPairViewController : OnboardingBaseViewController {
     }
     
     private func setUpViewHierarchy() {
+        // Prepare
         view.backgroundColor = Theme.backgroundColor
         view.layoutMargins = .zero
+        // Set up view hierarchy
         let titleLabel = createTitleLabel(text: NSLocalizedString("Create Your Loki Messenger Account", comment: ""))
         titleLabel.accessibilityIdentifier = "onboarding.keyPairStep.titleLabel"
-        let topSpacer = UIView.vStretchingSpacer()
-        let explanationLabel = createExplanationLabel(text: NSLocalizedString("Please save the seed below in a safe location. It can be used to restore your account if you lose access, or to migrate to a new device.", comment: ""))
-        explanationLabel.accessibilityIdentifier = "onboarding.keyPairStep.explanationLabel"
-        let bottomSpacer = UIView.vStretchingSpacer()
-        let registerButton = createButton(title: NSLocalizedString("Register", comment: ""), selector: #selector(register))
-        registerButton.accessibilityIdentifier = "onboarding.keyPairStep.registerButton"
-        let stackView = UIStackView(arrangedSubviews: [
-            titleLabel,
-            topSpacer,
-            explanationLabel,
-            UIView.spacer(withHeight: 32),
-            mnemonicLabel,
-            UIView.spacer(withHeight: 24),
-            copyButton,
-            bottomSpacer,
-            registerButton
-        ])
-        stackView.axis = .vertical
-        stackView.alignment = .fill
-        stackView.layoutMargins = UIEdgeInsets(top: 32, left: 32, bottom: 32, right: 32)
-        stackView.isLayoutMarginsRelativeArrangement = true
-        view.addSubview(stackView)
-        stackView.autoPinWidthToSuperview()
-        stackView.autoPin(toTopLayoutGuideOf: self, withInset: 0)
-        autoPinView(toBottomOfViewControllerOrKeyboard: stackView, avoidNotch: true)
-        topSpacer.autoMatch(.height, to: .height, of: bottomSpacer)
+        titleLabel.setContentHuggingPriority(.required, for: NSLayoutConstraint.Axis.vertical)
+        let mainView = UIView(frame: CGRect.zero)
+        mainView.addSubview(restoreStackView)
+        mainView.addSubview(registerStackView)
+        let mainStackView = UIStackView(arrangedSubviews: [ titleLabel, mainView, registerOrRestoreButton ])
+        mainStackView.axis = .vertical
+        mainStackView.layoutMargins = UIEdgeInsets(top: 32, left: 32, bottom: 32, right: 32)
+        mainStackView.isLayoutMarginsRelativeArrangement = true
+        view.addSubview(mainStackView)
+        // Set up constraints
+        mainStackView.autoPinWidthToSuperview()
+        mainStackView.autoPin(toTopLayoutGuideOf: self, withInset: 0)
+        autoPinView(toBottomOfViewControllerOrKeyboard: mainStackView, avoidNotch: true)
+        registerStackView.autoPinWidthToSuperview()
+        registerStackView.autoVCenterInSuperview()
+        restoreStackView.autoPinWidthToSuperview()
+        restoreStackView.autoVCenterInSuperview()
+    }
+    
+    // MARK: General
+    @objc private func enableCopyButton() {
+        copyButton.isUserInteractionEnabled = true
+        copyButton.setTitle(NSLocalizedString("Copy", comment: ""))
+    }
+    
+    // MARK: Updating
+    private func handleModeChanged() {
+        let registerOrRestoreButtonTitle: String = {
+            switch mode {
+            case .register: return NSLocalizedString("Register", comment: "")
+            case .restore: return NSLocalizedString("Restore", comment: "")
+            }
+        }()
+        UIView.animate(withDuration: 0.25) {
+            self.registerStackView.alpha = (self.mode == .register ? 1 : 0)
+            self.restoreStackView.alpha = (self.mode == .restore ? 1 : 0)
+        }
+        self.registerOrRestoreButton.setTitle(registerOrRestoreButtonTitle)
     }
     
     private func updateKeyPair() {
@@ -84,33 +151,50 @@ final class OnboardingKeyPairViewController : OnboardingBaseViewController {
     private func updateMnemonic() {
         mnemonic = Mnemonic.encode(hexEncodedString: keyPair.hexEncodedPrivateKey)
     }
+    
+    private func handleMnemonicChanged() {
+        mnemonicLabel.text = mnemonic
+    }
 
+    // MARK: Interaction
     @objc private func copyMnemonic() {
         UIPasteboard.general.string = mnemonic
         copyButton.isUserInteractionEnabled = false
         copyButton.setTitle(NSLocalizedString("Copied ✓", comment: ""))
         Timer.scheduledTimer(timeInterval: 4, target: self, selector: #selector(enableCopyButton), userInfo: nil, repeats: false)
     }
-
-    @objc private func enableCopyButton() {
-        copyButton.isUserInteractionEnabled = true
-        copyButton.setTitle(NSLocalizedString("Copy", comment: ""))
+    
+    @objc private func switchMode() {
+        switch mode {
+        case .register: mode = .restore
+        case .restore: mode = .register
+        }
     }
 
-    @objc private func register() {
+    @objc private func registerOrRestore() {
+        let hexEncodedPublicKey: String
+        switch mode {
+        case .register: hexEncodedPublicKey = keyPair.hexEncodedPublicKey
+        case .restore:
+            let mnemonic = mnemonicTextField.text!
+            do {
+                let hexEncodedPrivateKey = try Mnemonic.decode(mnemonic: mnemonic)
+                let keyPair = ECKeyPair.generate(withHexEncodedPrivateKey: hexEncodedPrivateKey)
+                // TODO: Store key pair
+                hexEncodedPublicKey = keyPair.hexEncodedPublicKey
+            } catch let error {
+                fatalError(error.localizedDescription) // TODO: Handle
+            }
+        }
         let accountManager = TSAccountManager.sharedInstance()
-        accountManager.phoneNumberAwaitingVerification = keyPair.hexEncodedPublicKey
+        accountManager.phoneNumberAwaitingVerification = hexEncodedPublicKey
         accountManager.didRegister()
-        let onSuccess: () -> Void = { [weak self] in
+        let onSuccess = { [weak self] in
             guard let strongSelf = self else { return }
             strongSelf.onboardingController.verificationDidComplete(fromView: strongSelf)
         }
         if let userName = userName {
-            // Try to save the user name
-            OWSProfileManager.shared().updateLocalProfileName(userName, avatarImage: nil, success: onSuccess, failure: {
-                Logger.warn("Failed to set user name")
-                onSuccess()
-            })
+            OWSProfileManager.shared().updateLocalProfileName(userName, avatarImage: nil, success: onSuccess, failure: onSuccess) // Try to save the user name but ignore the result
         } else {
             onSuccess()
         }

Signal/translations/en.lproj/Localizable.strings

@@ -2556,3 +2556,6 @@
 "Copy" = "Copy";
 "Copied ✓" = "Copied ✓";
 "Register" = "Register";
+"Restore" = "Restore";
+"Enter Your Mnemonic" = "Enter Your Mnemonic";
+"Restore Using Mnemonic" = "Restore Using Mnemonic";

SignalServiceKit/src/Util/ECKeyPair.h

@@ -0,0 +1,7 @@
+@import Curve25519Kit;
+
+@interface ECKeyPair (ECKeyPairExtension)
+
++ (nonnull ECKeyPair *)generateKeyPairWithHexEncodedPrivateKey:(nonnull NSString *)hexEncodedPrivateKey;
+
+@end

SignalServiceKit/src/Util/ECKeyPair.m

@@ -0,0 +1,27 @@
+#import "ECKeyPair.h"
+
+extern void curve25519_donna(unsigned char *output, const unsigned char *a, const unsigned char *b);
+
+@implementation ECKeyPair (ECKeyPairExtension)
+
++ (nonnull ECKeyPair *)generateKeyPairWithHexEncodedPrivateKey:(nonnull NSString *)hexEncodedPrivateKey {
+    NSMutableData *privateKey = [NSMutableData new];
+    for (int i = 0; i < hexEncodedPrivateKey.length; i += 2) {
+        char buffer[3];
+        buffer[0] = [hexEncodedPrivateKey characterAtIndex:i];
+        buffer[1] = [hexEncodedPrivateKey characterAtIndex:i + 1];
+        buffer[2] = '\0';
+        unsigned char byte = strtol(buffer, NULL, 16);
+        [privateKey appendBytes:&byte length:1];
+    }
+    static const uint8_t basepoint[ECCKeyLength] = { 9 };
+    NSMutableData *publicKey = [NSMutableData dataWithLength:ECCKeyLength];
+    if (!publicKey) { OWSFail(@"Could not allocate buffer"); }
+    curve25519_donna(publicKey.mutableBytes, privateKey.mutableBytes, basepoint);
+    ECKeyPair *result = [ECKeyPair new];
+    [result setValue:[privateKey copy] forKey:@"privateKey"];
+    [result setValue:[publicKey copy] forKey:@"publicKey"];
+    return result;
+}
+
+@end