noun
Technical term in computing; often abbreviated as 2FA.
アカウントのセキュリティを高めるために、ツーファクター認証を有効にしてください。
Please enable two-factor authentication to increase your account security.
Standard compound spelling; the most common written form.
Variant with a middle dot; less common but still seen.
Often used interchangeably, but 二段階認証 can refer to any two-step verification, while ツーファクター認証 specifically involves two different types of factors (e.g., password + biometric).
Wasei-eigo compound from English 'two-factor' and 認証 (authentication).