What is Application Level Encryption? Benefits & Implementation

In the modern era of data security, the critical issue lies in the implementation of encryption methods, not the encryption algorithms themselves. Application-level encryption stands out as a comprehensive way to secure sensitive data. This article will explore what application-level encryption entails, its benefits, its types, and how to implement it. We will also compare application-level encryption with other encryption methods and explore the challenges and considerations involved in using it.

What is Application-Level Encryption?

Application-level encryption is a security practice that involves encrypting data at the application layer, ensuring that data is protected before it is stored or transmitted. This method encrypts data as it is processed within the application, securing it from potential threats both during storage and transit. It parallels other encryption methods, such as disk-level or network-level encryption, providing a higher level of data protection by focusing on the application's context.

Types of Application-Level Encryption

Application-level encryption encompasses various methods for securing data at the application layer. By applying encryption directly within the application, you can control how data is protected and accessed. Here are some common types of application encryption:

• Field-Level Encryption: Field-level encryption involves encrypting specific fields within a data record. It helps protect against attacks where an adversary might gain access to full records, such as an unauthorized database access scenario. This method is useful for protecting sensitive data such as credit card numbers, social security numbers, or personal addresses. Field-level encryption protects data from insiders who may have access to the database. It allows for granular control over data security, ensuring that only particular data points are encrypted while other non-sensitive fields remain in plaintext.
• Record-Level Encryption: Record-level encryption encrypts an entire record in a database. This approach provides more comprehensive security for data, as each data record is fully encrypted. It helps protect against attacks where an adversary might gain access to full records, such as an unauthorized database access scenario.
• Full-Text Search Encryption: This type of encryption allows data to be encrypted while still enabling full-text search capabilities. It is a complex method that allows queries on encrypted data without compromising the data's confidentiality. Or it might slightly be giving away statistical hints about the cleartext underneath, although not practical in reality with big data sets.

Similar Encryption Mechanisms

While application-level encryption offers distinct advantages, it's important to distinguish it from other encryption methods, which have their own use cases and limitations:

Transparent Data Encryption (TDE):

TDE is a database-level encryption method that automatically encrypts entire databases, including tables, log files, and backups. It's managed by the database engine and does not require application code changes, providing security for data at rest. However, it lacks the granularity of application-level encryption and the protection against malicious administrators that field-level encryption provides, as it encrypts entire data sets rather than allowing for selective encryption of specific fields or columns.

Column-Level Encryption:

This method encrypts individual columns within a database table, offering more control than TDE by allowing the selection of specific columns to encrypt. However, it lacks context awareness of application-level encryption, which tailors encryption decisions based on the application’s logic. Column-level encryption applies uniformly across a column, missing the flexible, context-sensitive protection provided by application-level encryption.

What Application Level Encryption is Not

To fully understand the scope of application-level encryption, it's crucial to distinguish it from other encryption methods:

Network Encryption (TLS)

Network-level encryption, such as Transport Layer Security (TLS), is designed to secure data during transmission across networks. TLS encrypts data as it travels between systems, protecting it from interception or tampering by unauthorized parties (particularly in man-in-the-middle attacks). However, once the data reaches its destination, it is typically decrypted and stored in plaintext.

In contrast, application-level encryption, offered by service providers such as Thales, focuses on securing data within the application itself, even before it is stored or transmitted. This means that data remains encrypted throughout its lifecycle, providing continuous protection against unauthorized access. For example, by encrypting data at the application level, healthcare organizations that store personal information, such as users’ medical histories, can ensure this data remains secure throughout the storage and transmission process.

Application-level encryption complements network-level encryption, ensuring that data remains secure at all times, apart from momentarily when the data is accessed in the memory. Thorough encryption will also ensure that this memory is deleted when the request for data is completed, minimizing the attack surface in runtime that malicious actors can use to access the data.

Transparent Layers or DB Encryption Proxies

Transparent layers, such as database encryption proxies offered by service providers like Baffle, automate encryption and decryption at the database layer, providing seamless data security without requiring changes to application code. However, this transparency can limit the application's awareness of how data is being encrypted and decrypted, which results in less control and flexibility over data security. Also, since it’s transparent by design, it’s also transparent to attackers, who might gain access to the data.

Application-level encryption, on the other hand, requires explicit management of encryption and decryption processes within the application code. This approach gives developers more control over when and how data is encrypted, allowing for context-aware security measures and fine-grained access control. By directly managing encryption, the application can enforce more robust security practices tailored to specific data usage patterns and access requirements. When accessing data, it can leverage zero-trust security primitives such as JWT enforcement, tenant verification, etc.

Threat Model for Application-Level Encryption

Application-level encryption is critical for addressing a range of modern threats that target sensitive data in today's cloud production environments. Understanding the threat model associated with application-level encryption helps organizations effectively protect their data and mitigate risks. Here, we outline some common types of attacks and how application-level encryption can counter them:

• Database Breaches: Attackers may gain unauthorized access to a database using stolen credentials or exploiting vulnerabilities. Database leaks can have far-reaching effects, with incidents such as the recent Ticketmaster breach estimated to affect over 500 million users. By encrypting data at the application level, even if an attacker accesses the database, the data remains unreadable without the encryption keys.
• Insider Threats: Malicious insiders or employees may attempt to access data directly from the database. An insider threat incident in early 2024 resulted in tens of thousands of Verizon employees’ personal data being exposed. Application-level encryption ensures that only authorized applications with the appropriate keys can decrypt and access the data, thus mitigating the risk from insiders. The encryption keys are reserved exclusively for the production environment, reducing key-access exposure.
• Application-Level Attacks: Attackers may attempt to exploit application vulnerabilities to access sensitive data. In mid-2023, major security flaws in popular chat platform QuickBlox’s framework led to the exposure of millions of users’ sensitive information. By encrypting data at the application level and leveraging different encryption for different scopes of access, the risk of data exposure due to application vulnerabilities is minimized. Direct attacks on databases are futile since the data is already encrypted at the application layer. Technically, lateral movement (access to the database from the production environments by jumping from one machine to another all the way to the DB) is ineffective as the data remains encrypted at the DB level even if an attacker obtains the credentials. This raises the bar for attackers, who now need to either attack the application itself in order to execute malicious code from its context in runtime and obtain the encryption keys or access them indirectly. This makes it easier to monitor by looking for unusual activity in the application’s processes, such as crashes or weird operating system-level operations like IO to unused files or network drives.

Benefits of Application-Level Encryption

Application-level encryption is a powerful approach to securing data in modern cloud applications, offering multiple benefits while also presenting certain technical challenges. Let’s explore a little deeper into some of these benefits and challenges.

Doing application-level encryption securely means that keys never leave their storage scope (like HSM/KMS). And they should definitely not be distributed to various components within the architecture so they can directly encrypt/decrypt the data. Once such keys are compromised, so is all the data, losing its advantage. A similar challenge is that backups contain encrypted data and require access to the original encryption key to decrypt. If that corresponding key is lost over time, that backup is rendered unusable. The issue is that replicating the key is difficult if a hardware security module (HSM) is used. Products such as AWS KMS specifically support cross-region key replication to assist exactly with the backup. Now, let's take a closer look at some of the benefits of application-level encryption:

1. Data Protection on Underlying Layers

Encrypting data at the application level ensures that all data stored in underlying layers, such as databases or file systems, is already encrypted. This means that even if an attacker manages to gain unauthorized access to the database, they would only see encrypted data that is indecipherable without the proper keys. This additional layer of security reduces the risk of data breaches and safeguards against data theft, providing peace of mind to organizations handling sensitive information.

2. Access Control and Context Awareness

When encryption is managed at the application level, the application can implement fine-grained access control, granting permissions based on user roles and contexts. For instance, different users may have different levels of access to encrypted data based on their job functions or the data's sensitivity level. A European admin can access some data of European customers only. However, an American admin will see it masked. This context-aware approach allows for more precise and secure handling of data, ensuring that sensitive information is only accessible to those who need it and have the authority to view it. It basically opens a new set of privacy controls.

3. Enhanced Agility

Application-level encryption allows organizations to selectively encrypt data based on their security and privacy requirements. This flexibility enables the encryption of specific fields or data types, prioritizing the protection of highly sensitive data while allowing less sensitive data to remain unencrypted for performance or functionality reasons. This targeted approach supports compliance with regulatory requirements and industry standards while also enabling organizations to adapt their security measures as their needs evolve.

4. Secure Key Management and Rotation

Secure key management is crucial for maintaining the integrity and confidentiality of data in application-level encryption. Without proper key management, the security of the encryption process can be compromised. Effective key management involves several key components:

Key Storage and Protection:

One of the primary benefits of application-level encryption is that it allows for secure storage and protection of encryption keys. This involves safeguarding keys in a secure location, such as a hardware security module (HSM) or a dedicated key management service (KMS). By ensuring that keys are stored and used securely, you reduce the risk of unauthorized access or exposure to attackers. This level of control and oversight at the application level is essential to maintaining robust data security.

Key Rotation:

Regularly rotating encryption keys is a best practice in cryptographic security. It helps to mitigate risks such as key compromise, as even if a key is exposed, its usefulness will be limited by the frequent rotation. Key rotation also helps maintain data integrity and confidentiality over time, as outdated keys that might have been compromised are replaced with fresh ones. By automating key rotation, organizations can ensure that keys remain secure without causing unnecessary overhead for developers and engineers. Some regulatory frameworks require key rotation as a mandatory condition for compliance, and services such as AWS offer mandatory key rotation in the form of KMS (Key Management Services).

Effective key management and rotation form the foundation of application-level encryption, ensuring that data remains secure and protected from unauthorized access throughout its lifecycle.

Technical Limitations and Challenges

While application-level encryption is a robust security measure, it introduces certain challenges that require careful consideration:

• Search Limitations: Searching over encrypted data can be complex, as standard database indexing and querying methods will be broken with encrypted data. Developers need to implement advanced techniques such as blind indexes or membership-querying search algorithms, which can add complexity to the system and potentially affect performance.
• Performance Impact: The encryption and decryption process can incur performance overhead, especially when dealing with large volumes of data. However, today, modern processors support hardware-assisted encryption for improved performance, which should make it negligible. Developers might need to optimize their applications to mitigate any latency and ensure smooth operation.
• Complex Implementation: Application-level encryption demands meticulous design and coding to handle encryption processes and key management securely. Developers must be cautious about how data is encrypted and decrypted and how encryption keys are stored, used, and rotated, as any missteps can expose sensitive data to risks.

Application-Level Encryption Solutions

There are several solutions available for implementing application-level encryption:

Encryption SDK or ORM

Encryption SDKs (Software Development Kits) and ORM (Object-Relational Mapping) libraries, such as Django Cryptography’s encryption library, offer developers tools to integrate encryption into their applications seamlessly. These libraries typically provide pre-built encryption functions that simplify the process of securing data. Developers can focus on building their application logic while the SDK or ORM handles the complexities of encryption, decryption, and key management. Additionally, these tools may offer support for different encryption algorithms and methods, enabling developers to tailor their data protection strategy to the specific needs of their application.

Encryption-as-a-Service

Encryption-as-a-Service (EaaS) is a managed solution that allows developers to leverage cloud-based services for their encryption needs. These services provide APIs for encrypting and decrypting data, taking care of the underlying encryption processes, including key management, traceability, logging activity, data masking, data expiration, and more features on top of mere data cryptography. By using EaaS, developers can offload the operational overhead of managing encryption infrastructure and focus on building their applications. EaaS solutions often offer high scalability and integration with other cloud-based services, making them an attractive choice for modern applications that operate in cloud environments.

Using KMS to Derive Encryption Keys

Key Management Services (KMS) offer a centralized, secure way to manage encryption keys throughout their lifecycle. KMS can generate, store, and rotate encryption keys, ensuring that keys remain secure and are available when needed. By using KMS to derive keys, developers can benefit from robust security practices such as key wrapping, access control policies, and audit logging. KMS integrates seamlessly with other cloud services and can support multi-region deployments, making it an essential part of a comprehensive application-level encryption strategy.

Regulatory Compliance

Application-level encryption plays a crucial role in helping organizations achieve and maintain compliance with various regulatory frameworks such as GDPR, HIPAA, and PCI DSS. These regulations mandate strict standards for protecting sensitive data, such as personally identifiable information (PII), health records, and payment card data.

By implementing application-level encryption, organizations can encrypt data before it is stored or transmitted. This helps ensure that only authorized users can access and decrypt the data, significantly reducing the risk of unauthorized data exposure or breaches.

Key aspects of regulatory compliance that application-level encryption supports include:

• Data Protection and Privacy: Application-level encryption ensures that data remains secure throughout its lifecycle, helping to safeguard privacy and maintain confidentiality.
• Access Control: By encrypting data at the application layer, organizations can enforce fine-grained access control, ensuring that only authorized personnel can access or manipulate sensitive data. Everybody goes through one system to access the data, having auditing capabilities.
• Data Integrity: While encryption helps protect data from unauthorized access, ensuring data integrity requires additional anti-tampering measures. Tools like Vault support these features.
• Breach Notification Requirements: In the event of a data breach, encryption can reduce the impact by rendering the data unintelligible to attackers, which may affect notification requirements and potential penalties.
• Auditing and Monitoring: Application-level encryption can facilitate auditing and monitoring of data access, providing a clear record of who accessed or modified data and when, as it’s enabled only in sensitive data fields and not everything.

By providing robust data protection and access control, encryption not only helps organizations comply with regulatory requirements but also strengthens their overall data security posture.

How to Implement Application-Level Encryption

When implementing application-level encryption, it is important to take a methodical approach to ensure that data is properly secured. Let's expand on each step of the process with some code snippets and additional details:

1. Determine Data Sensitivity

First, identify which data needs encryption and prioritize based on sensitivity. Start by examining your application's data and determining which fields (data attributes) contain sensitive information such as personal data, financial data, or any other data that requires protection.

2. Select Encryption Method

Choose the appropriate encryption method (e.g., field-level or record-level) based on your application's needs. Field-level encryption encrypts specific data fields, while record-level encryption encrypts entire records.

3. Implement Secure Key Management

Use a secure key management solution to handle key storage and rotation. Proper key management is essential for maintaining the security of encrypted data.

4. Design Encryption Architecture

Plan how data will be encrypted, stored, and decrypted within the application. This involves designing the architecture to handle encryption efficiently and securely. Consider factors such as how encryption will be integrated with existing data storage and processing and how to manage encryption keys securely.

For instance, when designing an encryption architecture, you may need to decide when to encrypt and decrypt data, where to store keys, how to manage access control, and what microservices are allowed to access specific data scopes, etc.

5. Test and Monitor

Continuously test and monitor the encryption implementation for performance and security. Regular testing helps ensure that the encryption process works as expected and does not introduce performance bottlenecks.

Monitoring tools can help track the performance and security of your encryption implementation. Look out for signs of performance degradation or security vulnerabilities, and adjust your implementation as necessary.

By following these steps and ensuring that each aspect of application-level encryption is properly planned and executed, you can enhance the security of your application and better protect sensitive data.

Conclusion

Application-level encryption is a crucial approach to securing sensitive data within modern cloud applications against attackers. By integrating encryption directly into application code, organizations can achieve robust data protection that is both context-aware and highly granular. Piiano offers a comprehensive solution in the Piiano Vault, with powerful data protection APIs that empower developers to encrypt, tokenize, and safely store sensitive customer data with ease. This level of security provides confidence in compliance with regulatory standards like PCI-DSS, GDPR, and CCPA while also enhancing overall data privacy and security. With Piiano Vault, you can proactively secure customer data, streamlining your encryption efforts and staying ahead of modern threats.