Transparent Field-Level Encryption

Protect sensitive data without changing your applications

Transparent Field-Level Encryption (TFLE) protects sensitive data as it moves between applications and databases—without requiring changes to application code, database schemas or business workflows.

By operating directly on the database wire protocol, TFLE can identify sensitive fields in queries and responses, apply the appropriate protection policy, and dynamically enforce Row-Level Security (RLS) and Column-Level Security (CLS).

Data can be protected using:

• Tokenisation

• Format-Preserving Encryption, also known as vaultless tokenisation

• Standards-based encryption

The result is consistent, policy-driven data protection that remains transparent to applications, users and database infrastructure.

Security applied in the data path

Traditional approaches to field-level data protection often require developers to modify applications, integrate encryption libraries or redesign database schemas.

TFLE introduces a transparent security layer into the communication path between the application and the database.

As database traffic passes through the platform, TFLE:

1. Interprets the database wire protocol.

2. Identifies the user, application, query and requested fields.

3. Evaluates the applicable security and access policies.

4. Rewrites queries where necessary to enforce RLS and CLS.

5. Applies tokenisation or encryption to protected fields.

6. Returns authorised data in the form appropriate for the requesting user or application.

Applications continue to communicate with the database using their existing drivers and protocols. Protection is applied transparently, without requiring the application to understand how the underlying data is secured.

Dynamic Row-Level and Column-Level Security

TFLE uses contextual information available within the database session and wire protocol to make real-time access decisions.

Row-Level Security

Row-Level Security determines which records a user or application is permitted to access.

TFLE can dynamically modify database queries to restrict results according to attributes such as:

• User identity

• Role or group membership

• Business unit

• Customer or tenant

• Geography

• Data jurisdiction

• Application identity

• Purpose of access

This allows organisations to enforce data segmentation and least-privilege access even where native database RLS capabilities are unavailable, inconsistent or difficult to manage across multiple platforms.

Column-Level Security

Column-Level Security determines which fields a user or application can view and in what form.

Depending on policy, TFLE can:

• Return the original plaintext value

• Return a tokenised value

• Return a format-preserved encrypted value

• Return a masked or partially redacted value

• Return a standard ciphertext value

• Remove or replace the field entirely

The same database record can therefore be presented differently depending on who is accessing it and why.

For example, a customer service agent may see only the final four digits of a payment card number, while an authorised payment process can receive the full value.

Flexible protection for every data field

Different applications and business processes require different forms of data protection. TFLE supports multiple protection methods that can be selected at field level.

Tokenisation

Tokenisation replaces a sensitive value with a non-sensitive substitute.

The token can be used by applications and analytics processes without exposing the original information. Where authorised, the token can be exchanged for the original value according to policy.

Tokenisation is particularly useful for protecting:

• Payment card data

• Account numbers

• National identifiers

• Customer reference data

• Personally identifiable information

Format-Preserving Encryption

Format-Preserving Encryption protects the original value while retaining its expected structure and length.

This is sometimes described as vaultless tokenisation because the protected value can be generated cryptographically without requiring a central token vault to store a mapping between the protected value and the original data.

For example:

• A 16-digit card number remains a 16-digit value.

• A numeric customer identifier remains numeric.

• A fixed-length account number retains its original length.

This enables legacy applications, databases and validation processes to continue operating without schema changes.

Encryption

Standard encryption transforms a sensitive value into ciphertext using centrally governed cryptographic policies and keys.

Encryption is suitable where retaining the original format is unnecessary and strong cryptographic separation is the primary requirement.

Policies can define:

• Which fields are encrypted

• Which encryption method is used

• Which keys protect the data

• Who can decrypt it

• Under what conditions plaintext may be returned

Policy-driven protection

TFLE separates data security policy from application logic.

Instead of embedding protection rules into every application, policies can be centrally defined and consistently applied across database connections.

Policies can take into account:

• The requesting user

• The application or service

• The source network or environment

• The database, table or field

• The operation being performed

• The purpose of access

• The sensitivity or classification of the data

• Regulatory or jurisdictional requirements

This makes it possible to change how data is protected or presented without changing the applications that access it.

Transparent to applications and databases

Because TFLE operates at the wire-protocol layer, existing applications continue to use their normal database connections.

There is no need to:

• Modify application source code

• Add encryption SDKs

• Change database schemas

• Rewrite stored procedures

• Replace database drivers

• Re-engineer business workflows

The database can store protected values while authorised applications continue to work with the data they need.

This approach helps organisations introduce field-level protection across modern, legacy and third-party applications with significantly less disruption.

Protect data throughout its lifecycle

TFLE helps protect sensitive information as it is written to, stored in and retrieved from a database.

On write

When an application inserts or updates a sensitive value, TFLE identifies the protected field and applies the configured tokenisation or encryption policy before the value reaches the database.

The database stores the protected form of the data rather than the original plaintext.

At rest

Sensitive values remain protected inside the database, backups, replicas and downstream storage environments.

This reduces the risk associated with database compromise, unauthorised administrative access and uncontrolled data replication.

On read

When data is retrieved, TFLE evaluates the requesting identity and context.

Authorised users or applications may receive the original value. Other users may receive a tokenised, encrypted, masked or redacted version.

The decision is made dynamically for every request.

Consistent controls across heterogeneous environments

Organisations frequently operate multiple database technologies, applications and cloud environments. Native security controls can vary significantly between platforms.

TFLE provides a common policy and enforcement layer across supported environments, helping organisations apply consistent:

• Field-level encryption

• Tokenisation

• Dynamic masking

• Row-level filtering

• Column-level access controls

• Audit and governance policies

This reduces dependence on database-specific implementations and simplifies the management of data protection across complex estates.

Designed for zero-trust data access

TFLE applies the principle that access to a database does not automatically grant access to every value stored within it.

Every request can be evaluated using identity, context and data sensitivity before information is returned.

This allows organisations to:

• Reduce unnecessary access to plaintext data

• Limit the impact of compromised credentials

• Separate database administration from data access

• Apply least-privilege controls to applications and users

• Protect sensitive fields in shared data platforms

• Enforce tenant, regional and jurisdictional boundaries

Key benefits

Protect data without application changes

Introduce field-level protection without embedding encryption logic into every application.

Enforce RLS and CLS dynamically

Control which records and fields are returned based on identity, role, purpose and context.

Preserve application compatibility

Use tokenisation and Format-Preserving Encryption where applications depend on existing formats, lengths or data types.

Centralise policy and key governance

Manage protection rules and cryptographic controls independently of application release cycles.

Reduce exposure of plaintext data

Store protected values in the database and reveal plaintext only to explicitly authorised users and processes.

Support compliance and data sovereignty

Apply controls according to data classification, geography, jurisdiction and regulatory requirements.

Common use cases

TFLE can support a wide range of data-protection requirements, including:

• Protecting payment and financial information

• Securing personally identifiable information

• Enforcing tenant isolation in shared databases

• Restricting access by geography or jurisdiction

• Protecting sensitive data in legacy applications

• Applying consistent security across multiple databases

• Reducing developer access to production data

• Supporting secure analytics using tokenised values

• Separating privileged database access from access to plaintext

• Protecting data used by third-party and SaaS applications

Data security without application dependency

Transparent Field-Level Encryption moves security enforcement out of individual applications and into the data access path.

By understanding the database wire protocol, TFLE can protect sensitive fields, rewrite queries, enforce Row-Level and Column-Level Security, and dynamically determine how data should be presented to each user or application.

Organisations gain stronger control over sensitive data while preserving the applications, databases and workflows they already use.