Secure Hardening For Mobile Banking Apps: Data Masking

Mobile banking applications have become a popular and convenient way for customers to manage their finances on the go. However, given the sensitivity of financial data, it is crucial for mobile banking apps to implement robust security measures to safeguard user information. 

One increasingly important technique is data masking, which involves obscuring real data with realistic but fictional substitutions. This article explores the significance of data masking for securing mobile banking apps.

What is Data Masking?

Data masking is the process of obscuring original sensitive data with realistic but fake substitute data. It involves transforming confidential data elements so that they maintain key properties and utility, without exposing actual sensitive values.

Data masking provides the benefit of protecting end-to-end data from unauthorized access while still retaining utility through format-preserving fake data. It enables critical use cases not possible with data encryption alone.

Why Data Masking Matters for Mobile Banking Security

With mobile banking usage on the rise, application security is more vital than ever. Sensitive customer data such as account numbers, passwords, and financial transactions must be protected. Data masking provides an extra layer of security by substituting real data elements with fake ones that appear authentic. This protects the original data from exposure to unauthorized parties in the event of a breach while maintaining referential integrity for testing purposes.

Data masking enables compliance with regulations such as GDPR, which mandate privacy protections. It also promotes customer trust by demonstrating a commitment to data security. As threats evolve, data masking will continue to be an integral part of defense-in-depth strategies for securing sensitive mobile banking data.

Understanding Data Masking Techniques

There are several enforced data masking techniques in mobile banking applications:


Tokenization works by replacing sensitive data values with non-sensitive surrogate values called tokens. The token replaces the original sensitive value everywhere it exists. Tokens can retain the exact format of the original data to maintain syntactic integrity for applications. A tokenization engine manages the mapping between original data and tokens. Without the token-to-data mapping, tokens are meaningless.

Tokenization is highly effective for protecting stored data or data in transit. It can be implemented at the database layer or within the app code for field-level protection. Tokens generated at the app layer can then be stored in the database for persistent protection.


Encryption applies cryptographic algorithms to transform original sensitive data into encrypted ciphertext that looks meaningless. Authorized users with the cryptographic key can decrypt it back to usable form. Encryption protects data while at rest and in transit.

For mobile banking apps, field-level encryption can be applied to selectively encrypt sensitive data like account numbers in the database. Hybrid implementation may encrypt the entire database as well as encrypt selective fields for added protection. Format-preserving encryption retains the format of encrypted data fields.

Dynamic Data Masking

Dynamic data masking automatically obscures sensitive data in real-time when accessed by users that don’t require visibility of actual data. For example, call center staff may see only the last four digits of bank account numbers while chat support agents see random dummy account numbers. Only authorized backend users can view true data.

Dynamic masking rules can be defined programmatically at the database query level or app code level. Masking logic can leverage randomization algorithms to generate realistic fake data that appears authentic.

Integrating Data Masking into Mobile Banking Apps

To implement data masking, mobile banking developers first need to identify what data elements contain sensitive information requiring masking. The typical process includes:


  • Perform comprehensive data discovery using scanning tools to classify and tag sensitive data across app code, databases, and pipelines.
  • Identify fields containing personal identifiers, financial information, usernames, passwords, security questions, and other confidential data elements that need masking.
  • Create an inventory of sensitive data types with associated classifications and masking requirements.

Appropriate masking techniques are then selected based on factors such as data types, masking objectives, integration complexity, and performance considerations. For example:

  • Encryption may be applied to secure stored data at rest or in motion.
  • Tokenization can substitute sensitive data entered into forms or API calls.
  • Dynamic masking rules can be defined for real-time protection of specific fields.

Masking logic is added at either the database level using triggers and stored procedures or at the application level by incorporating masking libraries in app code. Embedding masking in API interfaces protects backend integrations.

Strict QA testing validates that masking rules are working correctly and do not break core app functionality that depends on the actual data properties. Automated testing with simulated masked datasets rapidly validates masking implementations.

The Benefits of Data Masking For Mobile Banking Security

Data masking strengthens the security posture of mobile banking apps in various ways:


Reduced Risk of Data Breaches

Masking directly minimizes the risk of sensitive actual data being extracted and exploited in the event of unauthorized access to databases, logs, source code repositories, or network traffic. Even if these components are compromised, critical data remains protected in meaningless masked form.

Prevent Data Exposure

Data masking techniques like dynamic masking and tokenization help limit insider threats from personnel such as developers, third-party vendors, outsourced teams, or partners who may have authorized access but don’t require viewing real sensitive customer data. The masked fake data prevents the exposure of true confidential data to unscrupulous insiders.

Enabling Compliance

Data masking facilitates compliance with data privacy regulations like GDPR that require de-identification of personal information. Masking data elements like names, national IDs and contact information demonstrates compliance with mandated privacy safeguards. Data masking also helps meet guidelines like PCI DSS for protecting cardholder information.

Building Customer Trust

Adopting robust data masking reinforces to users that the utmost care is being taken to safeguard their personal and financial information. Customers have greater confidence and trust in mobile apps that provably protect their sensitive data through masking, improving brand reputation.

Best Practices for Implementation

To maximize the benefits of data masking, banks should follow these best practices:

  • Identify all sensitive data that requires masking using data discovery and classification tools.
  • Select appropriate masking techniques based on data types, use cases, and security priorities.
  • Validate that masking logic works as intended and does not break core functionality.
  • Mask sensitive data as close to the point of entry as possible.
  • Implement just-in-time unmasking for authorized staff to view original data when required.
  • Mask data in logs, backups, and archives to protect stored information.
  • Periodically audit and update masking rules and algorithms to counter emerging threats.

Real-World Success Stories

Leading banks worldwide have already implemented data masking to enhance mobile security:

  1. A top 5 US bank uses tokenization to protect customer data and ensure PCI DSS compliance. This reduced their risk of data exposure by 80%.
  2. A major Canadian bank employs dynamic data masking to restrict the visibility of sensitive user data. This minimized insider threats while improving operational efficiency.
  3. An international bank based in Switzerland leveraged data masking to reduce its PCI DSS audit scope by 45%. This significantly lowered compliance costs.

These examples demonstrate how data masking tangibly improves security posture while driving operational benefits.

The Future of Data Masking for Mobile Banking

As mobile banking evolves, so will data masking capabilities. We can expect:


  • Increased adoption of advanced masking techniques like format-preserving encryption that retains the usability of masked data.
  • Tighter integration of data masking tools into CI/CD pipelines for automated, developer-driven security.
  • Enhanced regulatory focus mandating more rigorous data protections, especially for financial services.
  • Innovation in masking techniques to counter emerging threats from quantum computing and AI.

Banks that proactively embrace and integrate data masking into mobile apps will gain a competitive edge in security, compliance, and customer trust.


How does data masking differ from encryption?

Data masking substitutes original sensitive data with false fictional data, while still preserving referential integrity of the data relationships. Encryption scrambles the original data into unreadable ciphertext accessible only with the decryption key. While encryption protects data confidentiality, masked data can still be used for development, testing, and troubleshooting purposes.

Can data masking impact performance or functionality?

If not implemented properly, data masking can degrade performance and affect functionality that relies on true data properties. Banks should utilize optimized masking techniques and thoroughly test applications to avoid issues. The performance impact is usually minimal with well-architected masking integrated at the database layer.

What regulations mandate data masking for mobile banking?

Regulations like GDPR strictly require the protection of customer privacy. Guidelines like PCI DSS also recommend data masking as part of compliance. Adopting data masking demonstrates a commitment to best practice security. While no regulations currently mandate it, this could change as threats escalate. Proactive banks are deploying data masking now to get ahead.


As mobile banking expands, robust security is imperative, especially for sensitive customer data. Data masking provides an effective obscurity control by substituting production data with realistic but fake data. When implemented properly following best practices, data masking significantly improves mobile banking app security while enabling compliance and building customer trust. 

With imminent threats on the horizon, minimization through data masking will continue to grow as a critical pillar of defense-in-depth security strategies for mobile banking applications.

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