Apply email address and password recovery function to Login()

[tatsuyamoriguchi]

Sending credential information to email isn't secure way to recover it since you have access to email inbox on the same device.

Access Control: To access passwords stored in iCloud Keychain, users typically need to authenticate themselves using their device's passcode, Touch ID, or Face ID. This adds an extra layer of security to prevent unauthorized access to the stored information, even if someone gains physical access to the device.

Recovery: In the event that a user forgets their device passcode or loses access to their device, they can use Apple's account recovery process to regain access to their iCloud Keychain data. This typically involves verifying their identity through another trusted device or using account recovery methods such as answering security questions or receiving a verification code via SMS or email.

[tatsuyamoriguchi]

Sure! Here's a basic example of how you can use Keychain Services in iOS to securely store and retrieve sensitive information, such as passwords:

import Foundation
import Security

class KeychainManager {

    // MARK: - Constants

    private let serviceName = "YourAppServiceName"

    // MARK: - Keychain Access

    func savePassword(password: String, account: String) {
        guard let passwordData = password.data(using: .utf8) else {
            return
        }

        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: serviceName,
            kSecAttrAccount as String: account,
            kSecValueData as String: passwordData
        ]

        let status = SecItemAdd(query as CFDictionary, nil)
        guard status == errSecSuccess else {
            print("Failed to save password to keychain")
            return
        }

        print("Password saved successfully")
    }

    func retrievePassword(account: String) -> String? {
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: serviceName,
            kSecAttrAccount as String: account,
            kSecMatchLimit as String: kSecMatchLimitOne,
            kSecReturnData as String: true
        ]

        var result: AnyObject?
        let status = SecItemCopyMatching(query as CFDictionary, &result)
        guard status == errSecSuccess, let passwordData = result as? Data else {
            print("Failed to retrieve password from keychain")
            return nil
        }

        return String(data: passwordData, encoding: .utf8)
    }

    func deletePassword(account: String) {
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: serviceName,
            kSecAttrAccount as String: account
        ]

        let status = SecItemDelete(query as CFDictionary)
        guard status == errSecSuccess || status == errSecItemNotFound else {
            print("Failed to delete password from keychain")
            return
        }

        print("Password deleted successfully")
    }
}

In this code:

• The savePassword function is used to securely store a password in the Keychain.
• The retrievePassword function is used to retrieve a password from the Keychain.
• The deletePassword function is used to delete a password from the Keychain.

As for access control, you can specify access control attributes when adding items to the Keychain to control who can access the stored information. For example, you can specify that the item can only be accessed when the user has authenticated with Touch ID or Face ID.

Here's how you can modify the savePassword function to specify access control:

func savePasswordWithAccessControl(password: String, account: String) {
    guard let passwordData = password.data(using: .utf8) else {
        return
    }

    let accessControl = SecAccessControlCreateWithFlags(nil, kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly, .biometryCurrentSet, nil)

    let query: [String: Any] = [
        kSecClass as String: kSecClassGenericPassword,
        kSecAttrService as String: serviceName,
        kSecAttrAccount as String: account,
        kSecValueData as String: passwordData,
        kSecAttrAccessControl as String: accessControl
    ]

    let status = SecItemAdd(query as CFDictionary, nil)
    guard status == errSecSuccess else {
        print("Failed to save password to keychain")
        return
    }

    print("Password saved successfully")
}

In this modified version, the savePasswordWithAccessControl function adds an additional attribute kSecAttrAccessControl to the Keychain item, specifying the desired access control settings.

[tatsuyamoriguchi]

When utilizing Access Control in iOS Keychain to store credential information for an iOS app, the behavior can vary depending on how you've implemented it.

If you've configured Access Control to require biometric authentication (e.g., Touch ID or Face ID) before allowing access to the stored credentials, then the user would typically be prompted to authenticate using biometrics whenever the app attempts to access the stored credentials, regardless of whether manual credential entry succeeds or fails. This provides an extra layer of security by ensuring that only authorized users can access sensitive information stored in the Keychain.

However, if you've configured Access Control to only require biometric authentication when manual credential entry fails (for example, if the user enters the wrong password), then the user would only be prompted to authenticate using biometrics in those specific cases where manual credential entry fails. This approach provides a balance between security and convenience, as it only requires biometric authentication when necessary, such as in cases where there may be a potential security threat.

Ultimately, the specific behavior of the iOS Keychain in prompting for biometric authentication would depend on how you've configured Access Control within your app's implementation.