Hash/verify with bcrypt.
브라우저에서 처리 — 데이터가 기기를 떠나지 않습니다
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bcrypt is standard; still avoid shared screens.
No.
AES-256-GCM with passphrase.
Generate RSA/ECDSA PEM keys.
EN/JA word passphrases (CSPRNG).
Generate and verify TOTP codes.