Dynamic Format-Preserving Data Masking Without Static Lookup Tables

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Solution Overview

Problem

Current data masking tools lack security and efficiency in maintaining data format consistency and privacy, as they rely on static lookups that can be easily deciphered and consume significant disk space and processing time.

Innovation Solution

A format preservation based masking system that generates dynamic maps (dynamic map and MSB/NSB maps) to encrypt and mask data, ensuring data security and format preservation, supporting multiple languages and numerals without static lookup tables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If static predefined lookup is used for masking data, then data masking can be performed, but security is compromised as original data can be easily reproduced

Engineering Contradiction:
Improvedata securityVSAvoidmasking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from static lookup tables to dynamic masking functions that generate masks based on cryptographic algorithms. The masking mechanism becomes adaptive and context-dependent, using functions that take both the original data and a salt value as inputs, ensuring that the same original value produces different masks in different contexts, thereby preventing reverse engineering while maintaining manageable system complexity through standardized cryptographic primitives.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by introducing salt values and cryptographic function selections that transform the masking process. Instead of fixed mappings, the system uses variable parameters (salt, algorithm choice, key material) to generate masks, making the masking process dependent on multiple changing factors rather than static relationships, thus enhancing security without requiring overly complex custom implementations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If physical lookup tables are used for data masking, then data can be masked, but disk space consumption increases

Engineering Contradiction:
Improvedata privacy protectionVSAvoiddisk space consumption
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the masking logic from large physical lookup tables and replaces it with compact cryptographic functions. Instead of storing extensive mapping tables that consume disk space, the system extracts only the essential algorithmic logic needed to generate masks on-demand, significantly reducing storage requirements while maintaining privacy protection through mathematically secure masking functions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses cryptographic copying mechanisms where small seed values or keys can generate unlimited unique masks through deterministic functions. Instead of copying and storing large tables of pre-computed masks, the system uses compact key material that can algorithmically generate the necessary masks, reducing disk space consumption while ensuring each copy or instance can produce appropriate masks independently.

Inventive Principle:
Principle #26Copying

3Reliability

If static lookup masking is used, then data can be masked, but processing time increases due to large lookup tables

Engineering Contradiction:
Improvedata privacy complianceVSAvoiddata processing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by replacing static table lookups with dynamic cryptographic computation that generates masks in real-time based on input data and salt values. This dynamic approach eliminates the need to traverse large static tables, reducing processing time while maintaining privacy compliance through secure cryptographic functions that compute masks efficiently without requiring extensive pre-computed data structures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary action by pre-generating and storing only essential cryptographic parameters (such as salt values or key material) rather than pre-computing and storing all possible masks. This preliminary preparation of compact cryptographic state enables fast on-demand mask generation without the processing overhead of searching large lookup tables, improving productivity while ensuring privacy compliance through proper cryptographic setup.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3166041B1Format preserving masking system and method
Publication Date: 2025.11.26 TATA CONSULTANCY SERVICES LTD
  • EP3166041B1 patent drawingFigure 1
  • EP3166041B1 patent drawingFigure 2
  • EP3166041B1 patent drawingFigure 3A~3B

AI summary

A computer implement format preservation based masking system and method is provided. The system obtains a first set of letters and a private key, and encrypts the first set of letters to obtain an encrypted letters list using the first set and private key. The encrypted letters list comprises a set of encrypted letters. A dynamic map is generated based on the encrypted letters, which includes one or more keys, each key being specific to a letter in the first set letters. A position of each of maskable letters in a second set of letters is calculated using the dynamic map, and performs masking of the maskable letters based on the position of each of the maskable letters to obtain masked data using the dynamic map.