How RCS OTPs strengthen authentication and protect users

What if there was a way to always be sure that the person you're talking to is who they say they are? Businesses use one-time passwords (OTPs) to identify users globally. But with fraud in business messaging on the rise, consumers need secure, reliable ways to know they're communicating with a trusted brand rather than a fraudster. What if users could be sure they were always talking to your brand?

RCS messaging offers a way for customers to always know who they're talking wo while also giving businesses a way to authenticate users. Win-win! With business features like verified sender profiles and interactive branded messages, RCS messages are delivered to a user's native Android messaging app. And with Apple set to support RCS very soon, it's set to redefine how brands and users identify each other.

Let's jump into how sending OTPs via RCS can help your business and reassure customers with secure, trusted interactions.

What is an RCS OTP?

RCS OTP messages are a way for brands to send one-time passwords via Rich Communication Services (RCS). Basically, when a user needs to authenticate an account or transaction, they're sent a unique password via RCS to their registered mobile phone number that can only be used once and expires after a short period of time. This is done to add an extra layer of security as compared to just entering a username and password.

RCS OTPs are sent via RCS Business Messaging (RBM), which is the business solution. RBM accepts the following as OTP message scenarios :

• One-time passwords or two-factor authentication (2FA) messages for account log in

• Password resets

• Completing online commercial transactions

We'll dive into specific practices for each of these later, but it's also important to note what kind of content you're not allowed to send via an RBM OTP message:

• Product information and notifications

• Offers, promotions, discounts, upgrades, or information related to goods and services

Instead, RBM offers different message types for brands that want to send promotional or transactional messages, each of which has its own rules for what's allowed. Learn more about agent use cases for RCS business messaging.

SMS OTPs vs RCS OTPs

Short Message Service (SMS) is the default choice for sending OTPs because it's universal - everyone with a mobile phone can get SMS, no app is needed, and messages arrive almost instantly. However, SMS OTPs are vulnerable to types of fraud like smishing, where a fraudster impersonates a legitimate business. Brands can also face issues with Artificially Inflated Traffic (AIT), where large volumes of OTPs are sent but never delivered to an end user.

This is where RCS shines. RCS requires brands to be verified by a third party to use a name and logo, meaning that all branded messages come from verified sender profiles by default. Plus, RCS offers detailed analytics like delivery and read receipts so you can be sure messages are reaching customers.

Some may point out that while RCS is getting more popular, not all devices support RCS yet, which gives SMS a clear advantage. But with Apple set to support RCS in iOS 18, we expect RCS to become as common as SMS in the future.

Want to learn more? Providers like Sinch can help you send OTPs to phones that support RCS, and SMS to others. This way, your users get your messages, and they get the best experience possible no matter what kind of phone they have. Get in contact with our team to learn more.

How does the RCS OTP process work?

Now that you have a basic understanding of why a business might choose to send OTPs via RCS, let's talk about what it might look like in real life.

The process is super straightforward. In fact, from a customer's perspective, nothing changes in the 2FA process they're used to, except that the message comes from a verified sender. Here's what the RCS verification process looks like from the customer's perspective:

1. Receive a code: After entering their username and password on your site, users will get an RCS message with a one-time code.

1. Enter the code: Users open the message and enter the code on your website, app, or other platform to prove they're the rightful account owner.

1. Access granted: Once they enter the code correctly, their identity is confirmed, and they'll be granted access to their account.

It's as simple as that. There are no added steps for a customer to verify their identity via an RCS OTP versus an SMS one. The process not only helps brands verify identities, but also shows customers that they take security seriously.

RCS OTPs are great for banks or financial institutions that want to add security measures that will reduce user fraud.

Benefits of RCS OTPs

Generally, one-time passwords offer businesses enhanced fraud protection, global reach, and ease of use. They're also versatile and widespread because almost everyone has a mobile device.

But using RCS for OTPs brings even more advantages. Let's look at a few unique benefits RCS OTPs can offer your business.

Better security

One-time passwords are a surefire way to add a layer of security to your users' accounts. When you send OTPs via RCS, it not only adds legitimacy but also reinforces security, as recipients will see your official brand name, color, and a distinctive checkmark in each message.

If you're a bank or financial institution, it's worth noting that RBM complies with the EU Payment Services Directive 2 (PSD2), which requires Strong Customer Authentication (SCA). Since RBM is associated with an end user's verified phone number and SIM card, an OTP sent through RBM fulfills the "possession element" required by the European Banking Authority.

Branded messages build trust

We've mentioned branded sender profiles before, and they're worth emphasizing because they're a key benefit of RCS business messaging. These profiles signal that your messages are genuinely from your business, which helps with brand trust.

With RCS, a user can see from your business profile and in every message that the messages come from a verified source.

This visual cue of your branded identity on your business profile is especially important as you're sending OTPs because it assures subscribers that your messages aren't spoofed or fraudulent.

Ease of integration

When starting with a new rich messaging channel, you might worry about the hassle of integration, cost, and maintenance. And for some CPaaS providers offering RCS, that might be the case!

But for a lot of businesses working with Sinch, starting to send OTPs via RCS is super easy. And that's because many businesses can use similar pricing and the same API they already use for SMS OTPs to send RCS OTPs. This essentially means that SMS OTP messages are "upgraded" to RCS OTPs when the devices are RCS-compatible, while sending SMS OTPs to phones that aren't RCS-enabled. This makes it a super easy option for businesses that don't have the time or resources for a new API but still want to benefit from RCS.

This is exactly what EasyPark Group, the world leader in digital parking, did to send OTP messages in Germany. They were using multiple vendors for SMS reminders and OTPs globally, which meant spending a lot of time troubleshooting delivery issues in each country.

Switching to sending messages with Sinch simplified everything. Now, they send OTP messages as RCS when possible and SMS when the device isn't RCS-enabled.

Customers with Android devices know messages are coming directly from EasyPark because they're sent using RCS.

In Germany, about 40% of their messages are now sent via RCS, giving users visual reassurance that the messages are legitimate. The rest are delivered via SMS. Plus, their delivery rates jumped up to 97.4% with Sinch!

Use cases of OTPs for RCS

You might think that RCS OTPs can be used in all the same situations where you already use SMS OTPs. And you're probably right! Let's look at some common cases for sending OTPs via mobile channels and why RCS gives you an advantage.

Online payments

RCS OTPs are great for online payments, especially if you're a bank needing to verify customer transactions. And because RCS has the third-party verification requirement to use a brand name and logo, you reduce the risk of your customers falling prey to a SIM swap attack.

Alejandro Murcia, Director of Financial Services at Sinch, explains that SIM swap attacks can compromise OTPs. RCS can help mitigate this risk, especially when working with a reputable provider with direct operator connections.

Plus, because RCS messages don't have the same character limit as SMS, they can include the user's transaction details and other useful information which might help give them a better experience.

Account and identity authentication

Whether your company is a bank or a retailer, it's important to keep all customer interactions secure without slowing people down. If your account login or checkout process is too complicated, customers might look for easier options with your competitors.

RCS OTPs are perfect for adding security in account and identity authentication processes without extra steps. They deliver quickly, just like SMS, so your customers won't notice a difference - except they'll see your trusted, verified logo in every message. And a bonus? You can also use suggested replies and buttons so customers can reply even quicker to your messages. This way, you keep transactions safe and maintain a smooth user experience.

Password resets

You can also use RCS OTPs for password resets. When a user initiates a request, you can send an RCS OTP message to their registered mobile number to confirm their identity. Plus, from their perspective, the branded message arrives quickly, meaning they can complete the process without any hassle.

Access control

RCS OTPs are a great option to help ensure that only the right people can log in and access sensitive data or workflows. For example, if someone in the healthcare industry logs in to access confidential patient information, an RCS OTP can help verify their identity. This is also helpful for government services where only authorized individuals should be able to access certain information. And with RCS' enhanced security features and verified sender profiles, it's particularly suitable for industries where data integrity and confidentiality are important.

Start using RCS for user authentication

So, there you have it. Now you've seen how RCS can help add an additional layer of verification to help you make sure your customers are who they say they are. And at the same time, RCS helps your customers recognize and trust your brand with branded messages and third-party verification. By using RCS OTPs, you're both protecting your users and strengthening your brand's reputation. That's a win-win for security and customer satisfaction!

If you're looking to level up your authentication and verification knowledge, here are a great few places to start:

And if you're sold on RCS but now want to convince the rest of your organization, download our free guide on how to make a compelling business case for RCS. It has many more details about RCS and includes a ready-to-use business case template for you to use.

Public link

Please use the above public link if you want to share this noodl on another website.