Mastercard Continuous Authentication

Designing a new authentication system for Mastercard that replaces traditional passwords and 4-digit pins


Led 1-2 week sprints (using Agile methodologies) through which my team and I designed 9 prototypes, testing and validating each through multiple iterations of user tests.


8 months (January 2018 - August 2018)


Grace Guo, Zohaib Khan, Scott Leinweber, Aroon Mathai 🙋‍♂️, Xueting "Nika" Zhang


Contextual Inquiry, UX Research Methods, Prototyping, Product Management, Sprint Methodology


Our team at Carnegie Mellon University worked with Mastercard to explore a new payment authentication paradigm called Continuous Authentication.

While Continuous Authentication as a technology is ready to be incorporated in production applications, the user experience aspect is not yet fully thought through. Our team took on the challenge to create this consumer-facing experience for Continuous Authentication.

Our work was featured on the official Mastercard blog →


UX Guidelines for Continuous Authentication →

This project was sponsored by Mastercard. We consolidated 8 months of UX Research and design into a UX Guidelines website for Designers, Developers and other internal stakeholders at Mastercard to use as a reference before integrating Continuous Authentication into existing or new products.

The Problem


Traditional authentication system such as passwords, 4 digit pins and security questions to name a few are secure but they aren't convenient. All of us memorize several passwords only to forget them when you need them the most! As a fix, we sometimes use systems like Captcha and Security Questions but the problem with these systems are they are nowhere near as secure as less convenient systems.

Cartoon illustration of a girl suffering from the convenience security paradox. Not having to remember passwords would be convenient but she also does not want her identity to be stolen

The Convenience-Security Paradox

The Problem Redefined

How can we alleviate these security concerns for people, and simultaneously deliver a seamless checkout experience?

The Solution


Continuous Authentication is a new paradigm of authentication that is more secure AND more convenient than current methods. After seven months of human-centered user experience research, our team defines Continuous Authentication as a system that verifies who you are, whenever you need it, without you thinking about it.

Continuous Authentication uses an individual's information (factors) to identify them. This information ranges from traditional factors such as location data and biometric data to less common factors such as typing patterns (the way you type, how fast you type, etc.), sensor data (at what angle from the ground do you hold your phone generally). Using all this data, the system can identify you at any point in time. The moment you open Facebook, for example, your system will know it's you. You won't have to login and enter your password to prove it!

While this is clearly more convenient, it is more secure too! The more factors that the system uses the more secure you are. Traditional secure systems use a maximum of two factors (two factor authentication). Continuous Authentication can use up to 40 factors!

Continuous Authentication can use up to 40 factors to authenticate you


This sounds great on paper! In fact Mastercard even recently acquired a company, NuData Security that has the technology necessary to implement Continuous Authentication in Production. However, one major drawback is that people were uncomfortable with this system. Some people even found it invasive. Most people were not willing to provide all this data!

The Convenience-Security Paradox

Ideal Customer Journey


We needed to figure out a way to make Continuous Authentication more accessible and acceptable to consumers.


While on the subway, Mia gets a message from her bank informing her of a new service, Continuous Authentication. Mia goes through the in-app on-boarding and signs up. She gives permission to the service to collect data necessary for it to work effectively.

First Exposure and Onboarding


Mia continues to use her devices as usual. In the background, the app gradually learns her behavior patterns and its many nuances. It uses this information to create a virtual profile of her, that becomes more and more detailed over time.

Profile Formation


Once the system is confident that it can recognize Mia through her behavior, it authenticates her by itself. If she's on Facebook, it logs in for her. If she's shopping on Amazon, it fills in her details for her with high accuracy all the time.

Ideal Checkout Flow


However, there might be the rare occasion when the system is unable to recognize Mia. She might have bought a new device, or out of the country or maybe she's even being hacked! At this point, the system immediately steps up and asks for a traditional form of authentication like a password.

Step-Up Experience

User-Centered Research

Our final deliverable was and all of our decisions throughout the project was informed by over a 100 different users. We interviewed customers, merchants, academic experts and industry experts.

User testing with different stakeholders

Guerrilla Research Participants


Academic and Industry Experts


We tested and validated our hypothesis with the help of 9 prototypes ranging from low-fidelity mocks to hi-fidelity mocks to technical prototypes.

1. Avatar Game

A game for users to play to fill out their profile data

  • How do people respond to being asked to provide their personal data?
  • How can we succinctly convey the value of Continuous Authentication to the average Person?
  • Can "logging in" be playful or fun?

2. Avatar Storyboard

These avatar storyboards imagine a scenario where your credit card is so highly attuned to your mobile device, that handing your phone to someone else immediately shifts the payers identity to the person holding the phone.

  • How can we best demonstrate how Continuous Authentication works and its value?
  • How do people respond to being asked to provide their personal data?
  • In a physical space, how can this technology be more convenient than Apple Pay, or even just using your card?

3. Mastercard Instant Onboarding

A fictional micro-site through which users can learn and sign up for Mastercard Instant Checkout

  • How do we demonstrate how Continuous Authentication works?
  • How do people respond to being asked to provide their personal data?
  • How much do people want to see the details of background data collection?
  • Do they perceive background data collection as creepy? Trustworthy? Transparent?
  • Is transparency a requirement for trusting the system?

4. Small Merchant Checkout

We made a series of mid-fidelity prototypes for a small business checkout page for a desktop browser user. The small business, Haptic Labs, sells handmade soft goods and sundries. Their website uses Shopify for checkout and e-commerce.

  • How much background should be shown during checkout session?
  • How can we build trust in a Continuous Authentication interface?

5. Lemonade Stand

To branch into a physical experience, we set up a lemonade stand on the street. Visitors used a credit card on a POS tablet, and their personal details were filled out - magically!

  • How do people actually feel about their face being recorded in a physical store?
  • What should the recovery experience be at a physical POS?

6. Coffee Shop

To piggyback off the lemonade stand, we broadened our reach into a number of different interactions that could identify a customer at a point-of-sale in a store.

  • Onboarding - How does the person get in the system/sign up for the service? (Bank app, Apple Pay, Mastercard app)
  • Enter store - How does the merchant know you are inside the store?
  • Item Order - How is this assigned to your account?
  • Checkout - How does the merchant know your identity to make sure your order is charged to your account?

7. Bank App Onboarding

Over a few of these other prototypes, we started to create a couple different versions of an onboarding UI in different contexts (bank app, checkout, standalone app)

  • How do we communicate what Continuous Authentication is, how it works, and what value it provides?
  • What level of control fidelity do people want to see while onboarding?
  • Is security or convenience more valuable to customers while learning about it?

8. Mobile Checkout

While still investigating merchant adoption and integrations, we tested a number of options using a Pizza Hut mobile site.

  • Are merchant sites a reasonable context to opt-in interested customers?
  • Which do customers respond best to - convenience or security?
  • Which types of UI elements seem to convey security the most?
  • Where in a checkout flow is a reasonable spot to advertise this new service?

9. The Pager Study

To understand what is the best way to introduce Continuous Authentication to users without it appearing to be creepy or invasive, we conducted an extensive pager study with 20 participants over the course of 8 days.



We provided each user a credit card, with unique information. Each user browsed through one of 4 prototype websites we created every day, performed an action on the website and filled out a survey that contained questions regarding their experience and sentiment towards the website.

Users browsing through a website using custom card

The three big questions we wanted answered were:

  1. How do users feel, being monitored by the Continuous Authentication system?
  2. What is the best way to introduce Continuous Authentication to users? Do we not tell them anything? Do we keep them informed as much as possible?
  3. What is the best step-up experience, in case something goes wrong?

To answer these questions we split our users into 4 buckets. Users in each bucket would experience Continuous Authentication in different ways! The 4 buckets were:

The 4-Bucket plan for the Pager Study

  1. Bucket 1: No explanation or on-boarding is provided. Users have no control over what data is being collected
  2. Bucket 2: Minimum explanation is provided. Users are informed of the Continuous Authentication system and can opt-in
  3. Bucket 3: Minimum explanation is provided. Users experience the Continuous Authentication system and can opt-out
  4. Bucket 4: Extensive explanation and on-boarding is provided. Users have full control over what data is being collected


One very blatant finding was that users experienced and expressed a variety of very different emotions throughout the study. These emotions were more or less the same amongst users within the same bucket. We decided to plot it in the form of an emotion-cloud, across time to make more sense out of it.

The Emoji Graph depicting user emotion across 8 days


Out of all buckets, users in bucket 3 seemed to have enjoyed their experience the most relative to other buckets. These users experienced the convenience of Continuous Authentication and grew more and more used to it. However what made their experience better than users in other buckets was that they were given control to opt out of the service any time they wanted!

Consolidated results of emotion mapping

UX Guidelines


Communicate value instead of technical details

Instead of explaining why different types of data are being collected, explain in simple terms the benefit users will experience.

For example, by adopting Continuous Authentication, parents will not have to worry about children making online purchases without prior permission.

"I'd be happy that you're being protective but tracking my behavior? To heck with you!" Customer Journey Study

Learn more →

Educate and Re-Educate

Users rarely read!

Continuous Authentication as a concept takes a long time for users to intuitively understand. So messaging should be repeatedly conveyed in different ways, both through copywriting and UI micro-interactions.

"I don’t remember seeing this message!" Customer Journey Study
"I actually don’t remember if I opted out/in or not." Customer Journey Study

Learn more →

Leverage existing security mental models

Users liked to see how their decisions while opting-in to various types of data collection affected their security.

For example, a Weak-Medium-Strong progress bar, much like you may find while creating a password, to show how strong or weak their profile may be based on the data they're providing. Small micro-interactions like this can reinforce messages that slip through the cracks.

"The green check make me feel happy. It told me I'm verified. It reassures me that everything is working great." Mobile Checkout
Learn more →

Allow users to opt-out

Although all users may get some type of Continuous Authentication rolled out to them, they should still be given the option to opt-out or reduce its impact on their sense of privacy.

While it may not be legally required in some markets, user sentiment was higher when given the option to control their participation. See User Control, Consent, and Autonomy.

Learn more →

Make defaults secure and convenient

People don't want to think about security!

Many people will click through any messaging and ignore options for opt-in or opt-out. These users are busy, but should have a thoughtful experience too. In this way, consent can be assumed, as long as the new experience is perceptibly more valuable to them than the previous method.

Learn more →


Provide transparency during profile formation

While we simulated GDPR and non-GDPR customer journeys, both enjoyed having some control over their profile creation phase. While this may be highly varied among market and product, transparency during the early stages is preferred.

"From the point of view of being able to have control over your purchases and your activity online, autofilling without opt-in does not feel good." Customer Journey Study
"What do you know about me, Mastercard?" Customer Journey Study

Learn more →


Reduce cognitive load

An ideal convenient checkout experience should require minimal user attention.

"When I think about payments, I don't want to think about payments." Avatar Game

Learn more →

Celebrate convenience

Using a green check-mark or language like "you saved 3 minutes checking out!" to celebrate a convenient checkout.

Don't just explain how convenient the service is. It's hard for users to imagine how a new technology will work without experiencing it.

"It got easier, I surprised myself that I prefer automation so much." Customer Journey Study
"It's a little creepy but I'd use it. I forget my wallet all the time…" Lemonade Stand
"If my information is already filled out on there, I'm not gonna go back to Normal Checkout and delete it." Customer Journey Study
Learn more →

Rules of thumb, or heuristics, are powerful tools

Using pre-existing UI elements and content design is comforting to users, and enhances the experience as it reinforces their current mental model.

"The green check make me feel happy. It told me I'm verified. It reassures me that everything is working great." Mobile Checkout
Learn more →

Language is key

Some phrases can make people feel secure while others triggers nervousness.

Like UI elements, even text does very well, even if not read closely. A "Data is encrypted" phrase and a link to the Privacy Policy - even if it wasn't clicked on, made people feel much more secure. Just having a link to a Privacy Policy made the site feel safer for some.

Learn more →

UI elements should convey security

Small UI elements and micro interactions can make a page feel much more secure

"Check boxes help me know that I have to acknowledge and accept what I'm agreeing to…" Bank App Onboarding
Learn more →


Design an exit strategy

Sometimes, users are unable to navigate through a step up and the system should revert to a recovery scenario.

Users should always be aware as to why the security step-up was triggered.

Learn more →

Friction reinforces security

Some friction in the payment process may be preferable as it creates a sense of security as friction communicates that information is under protection.

When experiencing something new, people like to fall back on what they know. Leverage existing mental models and design experiences that are similar to what users already perceive as secure.

"I like a little bit of friction, otherwise I might overspend, I don't trust myself." Customer Journey Study
"Normally when I hit complete purchase, some sites say 'are you sure?', or 'confirm your purchase'. It's not just one click, for example, to make a decision. I like that [the ability] to rethink the purchase." Customer Journey Study

Learn more →

Final Deliverable

A UX Guidelines website that internal stakeholders like Product Managers, Designers and Developers at Mastercard can refer to before integrating Continuous Authentication into existing or new products.

Affinity Analysis on Pager Study notes

Affinity Grouping on Pager Study notes based on changing user emotion along the journey


We divided the information on our UX Guidelines website in to two groups. 1) Based on ideal customer journey and 2) Based on keywords

UX Guidelines Website - Information Architecture

UX Guidelines for Continuous Authentication →

This project was sponsored by Mastercard. We consolidated 8 months of UX Research and design into a UX Guidelines website for Designers, Developers and other internal stakeholders at Mastercard to use as a reference before integrating Continuous Authentication into existing or new products.

Product Roadmap

5 Year Product Roadmap for Continuous Authentication

Measuring Success

These are some metrics that would define whether the product is a success or not. Users can be categorized into different segments - customers, merchants and banks.


  1. Number of users that adopt Continuous Authentication.
  2. Number of new Mastercard users


  1. Number of users that complete onboarding
  2. Number of users that have weak profiles, by providing less than average amounts of data
  3. Number of users that have weak profiles, by providing average amount of data
  4. Number of users that have weak profiles, by providing more than average amounts of data
  5. Number of users that experience a step-up


  1. Churn rate (Number of users that opt-out)
  2. Customer satisfaction metrics, NPS scores


  1. Number of False Declines per unit time
  2. Net loss due to Identity Theft

Final Thoughts


One research question that was very important to the team but one that we were not able to work on, was how does Continuous Authentication work for users who might not be able to provide user data.

Intuitively, we believe there might be a lot of similarities to the way Continuous Authentication is implemented in countries governed by tight data privacy policies. Any Continuous Authentication product will have to be custom tailored from cultural and societal standpoints as well.


Many parents allow their children to use their credit card for specific situations. Other times, multiple family members or friends may use the same laptop, or even smartphone. How would Continuous Authentication work for scenarios like these?


In our Customer Journey Study we simulated streams in a GDPR and non-GDPR context. The GDPR sequence requires much more granular consent and permissions from the user, while the rest of the markets would need fewer permissions. However, it still is better for the user to tell them about what will be collected and let them decide if they want to be party to the service.


We did extensive prototyping and user testing to attempt to design for what the future of payments could look like in a physical space, using Continuous Authentication. A big constraint was that merchants should not have to buy additional hardware to make our solutions work (since that is how past experiments, like Google Hands Free, failed). What we found was that credit cards, especially the chip-and-PIN kind, work very well and we could not design a solution that worked better while meeting the constraint. However, this is an area that needs to be explored further.

How can we alleviate these security concerns for people, and simultaneously deliver a seamless checkout experience?

Answer: Building Trust

Throughout our research, we noticed that people considered a system trustworthy only when certain criteria were met. While it's easier said than done, you need 3 blocks to create trust. They are visibility, control and understandability.

Building Blocks of Trust