Last updated on March 26, 2024
The main difference between TOTP and U2F is that U2F is more secure and convenient to use than TOTP. U2F is more secure because it uses public-key cryptography and is phishing-resistant. Unlike TOTP, U2F is convenient to use because it does not require the user to type anything. Read on to learn more about TOTP vs. U2F.
What is Time-Based One-Time Password (TOTP)
Time-Based One-Time Password (TOTP) is an authentication method based on a shared secret between the user and the service provider. The shared secret is used to generate a one-time password that is valid for a short period of time. The user enters the one-time password along with their username and password to complete the login process.
TOTP is more secure than traditional passwords. This is because TOTP requires something the user has (their device) in addition to something they know (their password). As a result, MFA consisting of the password and the TOTP code makes it more difficult for attackers to gain access to user accounts.
There are two main implementations of TOTP:
- Software TOTP Token: An authenticator app that generates TOTP codes for enrolled accounts. You can install this app on your smartphone or tablet.
- Hardware TOTP Token: A simple key fob with a little display that shows the current value of the OTP. You have to carry this fob with you at all times, which is the main disadvantage of this TOTP implementation.
What is U2F?
Universal 2nd Factor (U2F) is an open authentication standard that enables users to securely access online services using a hardware key. U2F is based on public-key cryptography and provides strong multi-factor authentication. The hardware key generates a unique key pair for each service, which makes it more secure than traditional passwords.
U2F is supported by many popular web browsers and online services, including Google, Dropbox, and GitHub. It is also supported by many hardware vendors, including Yubico and Feitian.
Note that there is a difference between U2F and WebAuthn, the latter being a newer version of the former.
TOTP vs. U2F: Comparison Table
| TOTP | U2F | |
| Full Name | Time-Based One-Time Password | Universal 2nd Factor |
| Security | Lesser security because of not being phishing-resistant | Greater security thanks to being phishing-resistant |
| Cost | The software implementation is free for most services (e.g., Google Authenticator) | Requires a costly hardware key |
| Device Support | Most devices support TOTP | Limited device support for U2F |
| Cryptography | Symmetric Cryptography | Public Key Cryptography (Asymmetric) |
TOTP vs. U2F: What’s the Difference?
Time-based One-Time Password (TOTP) and Universal 2nd Factor (U2F) are Multi-Factor Authentication (MFA) methods that provide an extra layer of security to your online accounts. While both methods are effective in preventing unauthorized access to private and corporate accounts, they differ in terms of their implementation and security features.
In short, U2F is more secure than TOTP because it uses public-key cryptography and is more phishing-resistant. Unlike TOTP, U2F does not require the user to type anything, making it more convenient to use.
What follows are more differences between U2F and TOTP.
Difference 1: Usage and Generation
TOTP generates a unique code that changes every 30 seconds. It uses an extended HMAC algorithm and a secret key shared between the user and the service provider. Then, the user enters the code along with their password to gain access to their account. TOTP is widely used by many online services such as Google, Facebook, and Dropbox.
On the other hand, U2F uses a hardware device such as a USB key or NFC-enabled device to authenticate users. The device generates a public-private key pair that is unique to each service provider. When logging in, the user inserts the device into their computer or taps it on their phone and presses a button to authenticate themselves.
Difference 2: Shared Secret
TOTP is less secure than U2F because it relies on a shared secret between the user and the service provider. This shared secret can be compromised if the user’s device is infected with malware or if the user falls victim to a phishing attack. On the other hand, U2F uses a unique key per service, which makes it more secure than TOTP.
Difference 3: Cryptography
TOTP uses symmetric time-based one-time passwords for authentication, while U2F uses public-key cryptography to authenticate users.
Difference 4: Device Support
Most devices support TOTP, while U2F has limited device support. However, U2F is more secure than TOTP because it requires a hardware key.
Difference 5: Cost
TOTP is free for most services, while U2F requires a hardware key that you must buy. It is recommended to purchase at least two keys.
Difference 6: Convenience
An additional benefit of choosing U2F over TOTP is that U2F does the TOTP typing for you (YubiKey OTP Security Key). In contrast, you have to enter the TOTP code manually.
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TOTP vs. U2F: Which One is More Secure?
In general, U2F is more secure than TOTP. The three top reasons for this are:
- Phishing Protection: The primary benefit of a security key like a U2F device over a TOTP password is phishing resistance. U2F devices, when used with a web browser, receive the true URL from the browser itself and include it as part of the material when generating the signature. This makes it difficult for an attacker to trick a user into providing their credentials to a fake website.
- No Shared Secret: Unlike TOTP, which relies on a shared secret between the client and the server, U2F uses public key cryptography. This means that even if an attacker manages to compromise the server and steal the stored keys, they cannot use them to authenticate as the user.
- Stronger Protection Against MITM: U2F is less vulnerable to Man-in-the-Middle attacks. Even if an attacker is able to intercept the communication between the client and the server, they cannot use the intercepted data to authenticate as the user unless they also manage to impersonate the exact target domain.
TOTP vs. U2F: Which One Should You Use?
Choosing between a Time-Based One-Time Password (TOTP) and a Universal 2nd Factor (U2F) depends on your security needs and preferences. Both methods provide an extra layer of security to your online accounts, but they differ in terms of their implementation and security features.
If you’re looking for a simple and widely used MFA method, TOTP is a good choice. However, if you are looking for a more secure MFA method that is resistant to phishing attacks, U2F is the way to go.
Advantages of U2F Over TOTP
- Unlike TOTP, U2F is phishing-resistant, which makes it considerably more secure
- When using U2F, the user does not have to type anything versus typing the OTP manually when using TOTP
Advantages of TOTP Over U2F
- The main advantage of TOTP over U2F is that TOTP is less costly. This is because you can enable TOTP MFA for free by using a free OTP authenticator app on your smartphone. In contrast, U2F is tied to the FIDO security keys.
- Another upside of using software app-generated TOTPs is that users always have their smartphones with them anyway, whereas U2F is an extra piece of hardware they always have to have with them.
Yubico OTP
It is important to note that there is also the so-called Yubico OTP (YubiOTP, YubiKey OTP). Yubico OTP is an OTP feature built into some Yubico security keys that allows users to plug in their key, touch it, and get automatically logged in to their accounts. This is because after the user touches the key, the key automatically enters the code.
Use Both TOTP and U2F With Rublon MFA
Rublon Multi-Factor Authentication supports WebAuthn/U2F security keys, including YubiOTP capabilities. You can also use an authenticator app like Rublon Authenticator, Microsoft Authenticator, or Google Authenticator to log in to your Rublon-protected accounts.
Start a free 30-day trial and see for yourself.
U2F vs. TOTP: Conclusion
In conclusion, both TOTP and U2F are effective MFA methods that provide an extra layer of security to your online accounts. However, U2F is considered more secure than TOTP because it is resistant to phishing attacks. You can use FIDO security keys that support YubiOTP to enjoy the combined convenience and security of TOTP and U2F. Start a free trial of Rublon Multi-Factor Authentication and check how easily it aligns with WebAuthn/U2F security keys, Yubico OTP, and OTP authenticator apps.
