Why OTPs shouldn’t be part of a passwordless strategy

Feb 3, 2023 | Technology

One-time passwords (OTPs) are a common way to add an extra layer of security to an authentication process, but they can still be vulnerable to attacks and are not recommended as a sole means of authentication in a passwordless strategy.

OTPs rely on the assumption that the user receives the code securely, either through SMS or an authenticator app. However, this assumption can be flawed if the user’s phone or device is compromised or if there is a vulnerability in the system that allows the attacker to intercept the OTP. Additionally, OTPs can be lost, forgotten, or delayed, causing frustration for the user and potentially leading to security breaches.


A passwordless strategy that relies solely on OTPs may also not meet the needs of all users, particularly those with accessibility needs who may have difficulty receiving or entering OTPs.

Therefore, it is recommended to use OTPs in combination with other secure authentication methods, such as biometrics or push notifications, rather than relying solely on them as part of a passwordless strategy.

Another limitation of OTPs is that they can be vulnerable to phishing attacks. Attackers can create fake login pages or send phishing emails that ask the user to enter their OTP, allowing the attacker to gain access to the user’s account. OTPs can also be subject to replay attacks, where an attacker intercepts a valid OTP and uses it to gain access to an account.

OTPs are also not a permanent solution to authentication. They are meant to be used once and then discarded, requiring the user to request a new OTP each time they need to log in. This can be inconvenient and time-consuming for the user, especially if they need to access their account frequently.

Finally, OTPs may not be suitable for all types of organizations or applications. For example, high security environments such as banks or government agencies may require more secure authentication methods, such as multi-factor authentication or biometrics.

In summary, while OTPs can add an extra layer of security to an authentication process, they are not recommended as the sole means of authentication in a passwordless strategy due to their limitations and potential vulnerabilities.