What is Transparent Data Encryption (TDE)? Benefits, Types, and Best Practices

In today's digital landscape, data is an organization's most precious asset. A robust database must not only harness this data effectively but also safeguard it against increasingly sophisticated cyber threats.

As cyber attacks evolve in complexity, implementing a comprehensive data protection strategy has become imperative, particularly for organizations in highly regulated sectors such as finance and government. However, the repercussions of data breaches extend across all industries, inflicting substantial damage to both revenue and reputation.

To mitigate these risks, EDB Postgres offers a diverse array of encryption options at various levels, providing flexibility in shielding data from potential breaches due to server theft, unethical administrators, or vulnerable networks.

Here, we’ll specifically look at Transparent Data Encryption, also known as TDE.

What is Transparent Data Encryption?;

Transparent Data Encryption (TDE) serves as a cornerstone of database encryption, offering file-level encryption that addresses the challenge of protecting data at rest. By encrypting databases on both hard drives and backup media, TDE helps organizations meet compliance requirements such as PCI DSS, which mandates the protection of data at rest.

Supported by version 15 of EDB Postgres Advanced Server and EDB Postgres Extended Server with the EDB Standard Plan, TDE is an optional feature that significantly enhances security for data management systems.

Beyond compliance, TDE safeguards sensitive and confidential information by rendering it unreadable to unauthorized entities. It employs key management to regulate data access, with keys functioning as unique "decoder rings" that unlock encrypted data.

Unlike Community Postgres, which lacks TDE capabilities, EDB Postgres' inclusion of this feature makes it a viable choice for regulated industries and government agencies requiring PCI compliance or adherence to additional data-at-rest regulations.

The inclusion of TDE in these Postgres versions opens doors for organizations that previously found it challenging to adopt Postgres due to stringent security requirements.

What is Encrypted with TDE?

TDE's encryption coverage extends to:

• Files underlying tables, sequences, and indexes, including TOAST tables and system catalogs—including all forks. These files are known as data files.
• Write-ahead log (WAL) files
• Temporary files for query processing and database system operation

However, TDE does not encrypt:

• Metadata internal to operating the database system that doesn't contain user data, such as the transaction status (for example, pg_subtrans and pg_xact).
• The file names and file system structure are in the data directory. The overall size of the database system, the number of databases, the number of tables, their relative sizes, as well as file system metadata such as last access time are all visible without decryption.
• Data in foreign tables, server diagnostic logs, configuration files, etc.

How Does TDE work?

TDE prevents unauthorized access to data within operating system files on both the database server and backup storage. In the event of theft or misplacement, the data becomes indecipherable to unauthorized users.

The database manages data encryption and decryption processes, eliminating the need for application modifications or updated client drivers.

EDB Postgres Advanced Server and EDB Postgres Extended Server provide integration hooks for external key management solutions. These hooks facilitate simple passphrase encrypt/decrypt operations or integration with enterprise-level key management systems.

Transparent Data Encryption in PostgreSQL

Transparent data encryption (TDE) in PostgreSQL refers to the process of encrypting data at rest. This means it secures the data stored on disk, including tables, indexes, and write-ahead log (WAL) files, without requiring modifications to the applications that interact with the database. However, PostgreSQL does not natively support TDE in the same way that other database systems do. Instead, encryption is typically implemented using third-party extensions, such as pgcrypto.

TDE entails encrypting data files, including the database’s storage files, logs, and backups. This measure ensures that even if the physical storage becomes compromised, data remains secure. PostgreSQL allows encryption of individual columns using functions like pgcrypto, which allows for more granular control. Because this is not fully transparent, the application must specify which data needs to be encrypted and how.

A commonly used method for full disk encryption is to utilize filesystem-level encryption tools like LUKS (Linux Unified Key Setup) or BitLocker. These tools automatically handle encryption without necessitating changes at the database level. While they are effective, these methods can increase processing loads, which may result in some performance trade-offs.

Furthermore, TDE relies on a key management system to securely store and manage the encryption keys. Therefore, it is vital to ensure proper key management, as this aims to prevent unauthorized access to critical encrypted data.

Using pgcrypto requires installing the extension in the PostgreSQL database. From this point, you can access various functions to encrypt and decrypt data. 

Use Cases for Transparent Data Encryption

TDE is a widely adopted method used for protecting sensitive data at rest across different contexts, as it offers an additional layer of security. With TDE encrypting the entire database or data files to protect sensitive data from unauthorized access, its applications are widespread. They commonly include the following use cases:

Financial Services 

Financial institutions store sensitive customer data, such as account details, transaction records, and personal identifiers. TDE ensures this data is encrypted, reducing the threat of data breaches or exposure and the monetary consequences that can occur as a result. Additionally, because financial services must adhere to strict regulatory standards, including the Payment Card Industry Data Security Standard, to protect payment card data, TDE ensures encryption of data, helping meet these requirements.

Healthcare

Healthcare providers handle highly sensitive patient information, such as patient records, treatment plans, and medical histories. Therefore, data security is a critical component of medical business and operations. TDE helps to ensure this data cannot be accessed by unauthorized individuals, preserving patient privacy and meeting HIPAA’s data encryption and security expectations.

Cloud Storage 

As organizations migrate data to cloud environments, TDE provides a seamless solution, encrypting data to protect sensitive information before it gets there. This security measure is especially vital as cloud providers often provide services to multiple clients, meaning not just your data is stored on the same infrastructure. TDE ensures that each customer’s data is securely encrypted and isolated, preventing it from mistakenly being accessed by other tenants.

Regulatory Compliance 

Many industries are governed by a combination of regulatory frameworks and industry standards with the goal of protecting consumers and the public. For organizations, failing to abide by their specific regulations can lead to severe penalties and outcomes. TDE helps ensure organizations remain compliant and do their part in meeting expected data protection standards. 

Keep Your Data Protected: Why Use TDE?

Recent high-profile data breaches, such as the car rental agency incident in late 2022, underscore the critical importance of robust database security. In this case, hackers exfiltrated substantial amounts of personally identifiable information (PII) from a MySQL database via Amazon RDS/EBS snapshots.

Such incidents, while varying in scale, are alarmingly common across organizations of all sizes and industries worldwide. The consequences of these breaches extend beyond immediate financial losses to include legal ramifications and compliance violations.

To mitigate these risks, it's crucial to fully understand and effectively deploy your Postgres database's security features. While TDE forms a foundational component of this security strategy, it represents just one of many available tools.

Postgres has earned a reputation for its comprehensive encryption capabilities, empowering organizations to protect themselves from becoming the subject of the next major data breach headline.

Investing in Postgres means investing in your organization's security. By leveraging its powerful encryption features, including TDE, you can significantly enhance your data protection measures. Explore Postgres' powerful encryption capabilities in our 2023 white paper, "Security Best Practices for PostgreSQL."

Best Practices for Transparent Data Encryption

 Key management is crucial for TDE and preventing unauthorized access to critical data. To bolster security, regularly rotate encryption keys to minimize the risk of compromise and introduce key expiry policies to guarantee keys are replaced periodically. Additionally, limit access to encryption keys to only necessary personnel or services.

Performance Tuning 

Due to the encryption and decryption processing associated with TDE, database performance may suffer. To minimize overhead, use hardware acceleration for encryption operations when possible. Another way to minimize TDE’s effect and maintain optimal performance is by tuning database settings and regularly monitoring the system’s output.

Access Control 

Ensure that only authorized users or processes can access encrypted data by enforcing control policies. You can also define roles to give certain users access only to the data that aligns with their function.

Routine Auditing and Checks 

To confirm that TDE implementation is consistent with organizational policies and adheres to relevant regulatory requirements, conduct regular audits and checks. This process can be automated and should include details surrounding who accessed the data, when, and what operations were performed.

Alignment with Organizational Policies 

When implementing TDE, ensure it aligns with your organization’s overall data protection strategy, security policies, and risk management framework, while taking into consideration specific encryption needs and compliance requirements. Furthermore, establish clear roles for managing the encryption and decryption processes, key management, and auditing for proper oversight and accountability.

Disaster Recovery Planning 

It is wise to incorporate TDE into your disaster recovery planning in the event you need to restore encrypted data due to a system failure or data loss.