https://support.apple.com/guide/security/escrow-security-for-icloud-keychain-sec3e341e75d/1/web/1 https://support.apple.com/guide/security/escrow-security-for..

https://support.apple.com/guide/security/escrow-security-for-icloud-keychain-sec3e341e75d/1/web/1 https://support.apple.com/guide/security/escrow-security-for... https://support.apple.com/guide/security/secure-icloud-keychain-recovery-secdeb202947/1/web/1 https://support.apple.com/guide/security/secure-icloud-keych... https://support.apple.com/en-us/HT213305 https://support.apple.com/en-us/HT213305 Basically: For some subset of iCloud Keychain users, SMS is used in combination with the lost device's passcode (or a user-chosen password) to recover the keychain. Since the device is lost, you re-issue the phone number with a carrier. I think 2FA or ADP may require another device or a recovery key, but my memory is hazy on this.