Could you tell me about account security and passkeys? Our service is considering implementing passkeys, and these questions are to understand how Apple protects accounts from third parties. ① Apple website states that two-factor authentication is mandatory for newly created Apple Accounts. When did this requirement come into effect? What are the conditions for users who do not have two-factor authentication enabled? ② Apple website mentions that a verification code may be required when signing into an Apple Account from a new device or browser. Is my understanding of the situations where a verification code is requested accurate, as listed below? Are there any other situations? Completely signing out of the Apple Account on that device. Erasing the device. Needing to change the password for security reasons. ③ If a user is already using a passkey on an Apple device, and then upgrades to a new device, will additional authentication, such as entering a PIN code, be required to use the passkey on the new device?

hello, I'm writing to seek clarification on Apple account security, particularly regarding potential risks of compromise, implemented safeguards, and residual risks with corresponding mitigation strategies. We would appreciate your insights on the following specific points: iCloud Keychain Access: Is an Apple ID login strictly required to access iCloud Keychain? We understand that a compromise of iCloud Keychain is unlikely unless a malicious actor successfully takes over the legitimate user's Apple ID. Is this understanding correct? Passkey Theft Methods and Protections: What are the conceivable methods a malicious actor might employ to steal a legitimate user's passkey, and how are these attempts protected against? Impact of Apple ID Compromise on Passkeys: If a malicious actor successfully compromises a legitimate user's Apple ID, is it accurate to assume that the legitimate user's passkeys would then synchronize to the attacker's device, potentially allowing them to log in using their own biometrics? Authorization Flow on Legitimate User's Device: Could you please detail the authorization flow that occurs on the legitimate user's device? We are particularly interested in the types of authentication involved and the conditions under which they are triggered. Detection and Additional Authentication for Unauthorized Login: How are attempts to log in to an Apple ID from an unrecognized device or browser detected, and what additional authentication steps are implemented in such scenarios? Thank you for your time and assistance in addressing these important security questions.