Passwords alone are no longer enough to protect online accounts. Two-factor authentication (2FA) adds an additional security layer that significantly reduces the risk of unauthorized access.
What Is 2FA?
2FA requires users to verify their identity using two different factors:
- Something you know (password)
- Something you have (OTP code, device)
- Something you are (biometrics)
Most online services today use OTP-based 2FA.
How OTP-Based 2FA Works
OTP (One-Time Password) codes are temporary and expire quickly. The most common formats include:
- HOTP (counter-based)
- TOTP (time-based)
TOTP is widely adopted due to its simplicity and security.
How Users Generate OTP Codes
Traditionally, OTP codes are generated using mobile authenticator apps. However, online generators are also used for:
- Learning how 2FA works
- Testing authentication systems
- Temporary access scenarios
For example, https://2fa.cn provides a free online way to generate OTP and TOTP codes for testing and educational purposes.
Why 2FA Is Important
- Protects against password leaks
- Reduces phishing risks
- Improves account security
Conclusion
2FA is now a standard security requirement. Understanding how OTP systems work helps users and developers adopt safer authentication practices.
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