How to correctly send OTP codes
In an increasingly digitalized environment, protecting user accounts is crucial due to the rise in fraud and cybercrime. Implementing two-factor authentication (2FA) methods and OTP codes is inevitable to ensure security.
This article explains how to perform these authentication processes to make them 100% secure and accessible to any user.
Última modificación: 07.22.2024
Index
What is an OTP Code and What is it For?
An OTP (One-Time Password) code is a password that is only valid for a single transaction or authentication session.
These codes are fundamental in any security process that requires 2FA. Their use reinforces protection beyond the simple use of a password.
OTP codes can be used in combination with various forms of authentication, such as traditional passwords, biometric elements, or physical keys (USB). This makes any verification process more robust and less vulnerable to cyberattacks.
OTP codes have several distinctive characteristics:
- Generation and Limited Validity. An OTP code must be generated for a single process and have a limited validity, generally from 5 to 30 minutes. This feature ensures that the code cannot be reused, increasing security.
- Simplicity and Versatility. The code can be numeric or alphanumeric, simple to remember, and easy to enter. It is important that the system allows retries through different channels, ensuring it works even if there are issues with one of them.
- Inclusion of Direct Login Links. To facilitate the user experience, a direct login link can be included in the OTP message. This avoids the user having to type the code, streamlining the authentication process.
How to Send an OTP Code
The 2FA authentication process generally begins with user validation via username and password. Then, an OTP code is sent to the user. The user must enter the received code in an app or website to complete the verification.
OTP codes can be sent to users in various ways. Common methods include SMS, email, voice call, in-app notification, code generation apps like Google Authenticator, and even postal mail in less common cases.
Comparison of OTP Delivery Channels
Benefits and Problems of Different Channels
It is crucial to compare the different communication channels to send OTP codes. Each method has its own advantages and disadvantages in terms of security, accessibility, and speed.
OTP Delivery Channels Comparison Table
| Channel | Benefits | Problems |
|---|---|---|
| SMS | Fast and direct access, widely used | Vulnerability to SIM swapping attacks |
| Easy to use, accessible from multiple devices | Risk of phishing and delivery delays | |
| Wide acceptance, fast and direct access | Requires internet connection and registered number, may be less secure than other methods | |
| Voice Call | Ideal for users with visual impairments | Susceptible to interceptions and less convenient |
| In-App Notification | Secure and fast, less intrusive | Requires having the app installed and internet connection |
| Code Generation App | High security, independent of communication channel | Requires prior installation and configuration |
| Postal Mail | Useful in areas without digital access and validation of a postal address. | Very slow, not viable for urgent transactions |
How to Choose and Implement OTP Delivery Channels
Adapt Channels to Users and Processes
It is essential to adapt the available channels according to the type of users and the characteristics of the authentication process. For example, users with visual impairments may prefer voice calls, while young and tech-savvy users may opt for in-app notifications or code generation apps.
Set an Appropriate Expiry Time
The OTP code's expiry time should be reduced and adapted to each channel. For example, a code sent by SMS can expire in 5 minutes, while one sent by email may have a slightly longer validity period due to possible delivery delays.
To facilitate the user experience, it is advisable to include a direct access link in the OTP message. This allows the user to access directly without having to enter the code. This functionality is especially useful in channels such as SMS or email.
It is important to set a limit on OTP retries. If a user reaches the maximum number of allowed retries, a support contact method should be included to assist in authentication. This helps prevent blockages and improves the user experience.
Country and Device Restrictions
Limiting access based on the user's country of origin can enhance security. The country of origin or device (using a fingerprint) of each user should be stored, and security conditions should be strengthened if access is attempted from a new device or location. This adds an additional layer of protection against unauthorized access.
What to Consider Regarding the SMS Channel
Professional and Reliable SMS Platform
It is crucial to hire a professional and reliable SMS platform and avoid gray and low-quality routes. It is important to contact the platform's support to ensure that OTP or transactional priority routes are configured, guaranteeing that SMS messages arrive without delays.
Validation of SMS Content
Validate through individual or mass tests that the SMS message text is not blocked. Ensure that the message, including the OTP, is delivered correctly.
Telecommunications Regulations
Verify if the users who will request OTP codes via SMS belong to countries with prior or additional requirements according to telecommunications regulations, such as the US, UK, Morocco, UAE, etc.
Correct Mobile Number Acquisition
Validate that mobile numbers are being obtained correctly from users. This can be done by sending an OTP code to ensure that the number belongs to the user.
Message Delivery Verification
Obtain the history of sent messages and validate that they are being delivered correctly and correspond to successful 2FA validation processes. If there are problems, contact the SMS platform's support to resolve them.
Conclusion
In a digitalized environment, protecting user accounts is crucial due to the rise in fraud and cybercrime. Therefore, the implementation of two-factor (2FA) and OTP code processes is essential.
Following this article, you can obtain the keys to optimize any authentication or verification process, not only to strengthen security but also to improve usability and accessibility for users.
LabsMobile offers efficient solutions to develop and implement authentication and verification processes by sending OTP codes via SMS.
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