Onion Encryption for In-Memory Column Store

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Solution Overview

Problem

Current data handling in the cloud faces security challenges due to the risk of unauthorized access, and existing encryption methods can interfere with data processing, limiting the value of Database-as-a-Service (DaaS) schemes by restricting query processing to the client side.

Innovation Solution

The implementation of an adjustable onion encryption procedure that translates SQL queries into equivalent queries on encrypted data, allowing for secure and efficient processing by selecting appropriate encryption layers based on policy configuration, alternative resolution, and conflict resolution, and employing searchable and homomorphic encryption to facilitate local execution and aggregation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encryption is applied to data stored in the cloud, then security is improved, but data processing capability deteriorates

Engineering Contradiction:
ImprovesecurityVSAvoiddata processing capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments encryption into multiple layers (onion encryption model) where different layers provide different levels of security and processing capability. The outer layers provide strong security while inner layers allow efficient processing, resolving the contradiction between security and processing capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces encrypted indexes as an intermediary structure that enables efficient query processing on encrypted data without requiring full decryption. This mediator allows the system to maintain both security (data remains encrypted) and processing capability (queries can be executed efficiently).

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If data is encrypted before storing in the cloud, then confidentiality is improved, but query processing flexibility deteriorates

Engineering Contradiction:
ImproveconfidentialityVSAvoidquery processing flexibility
Core Design Contradiction:
Loss of informationVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic onion layer peeling where encryption layers are selectively removed based on query requirements. This dynamic approach allows the system to adapt between strong encryption (when not querying) and processing flexibility (when querying is needed), resolving the contradiction between confidentiality and query processing flexibility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the encryption parameter state by transitioning from fully encrypted to partially decrypted states based on query needs. This parameter change allows the system to maintain confidentiality while enabling flexible query processing when required.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If strong encryption schemes are used, then security is improved, but computational overhead increases

Engineering Contradiction:
ImprovesecurityVSAvoidcomputational overhead
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial decryption (peeling only necessary onion layers) rather than complete decryption or using overly strong encryption for all operations. This partial action approach maintains security where needed while reducing computational overhead for routine operations.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent applies different encryption strengths to different data layers and access patterns. High-security strong encryption is applied to outer layers that require strong protection, while inner layers use lighter encryption schemes that enable efficient processing, resolving the contradiction between security and computational overhead.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2876573B1Encrypted in-memory column-store
Publication Date: 2016.11.16 SAP SE
  • EP2876573B1 patent drawingFigure 1
  • EP2876573B1 patent drawingFigure 2
  • EP2876573B1 patent drawingFigure 3A

AI summary

Embodiments relate to processing encrypted data, and in particular to identifying an appropriate layer of encryption useful for processing a query. Such identification (also known as the onion selection problem) is achieved utilizing an adjustable onion encryption procedure. Based upon defined requirements of policy configuration, alternative resolution, and conflict resolution, the adjustable onion encryption procedure entails translating a query comprising an expression in a database language (e.g. SQL) into an equivalent query on encrypted data. The onion may be configured in almost arbitrary ways directing the onion selection. An execution function introduces an execution split to allow local (e.g. client-side) query fulfillment that may otherwise not be possible in a secure manner on the server-side. A searchable encryption function may also be employed, and embodiments accommodate aggregation via homomorphic encryption. Embodiments may be implemented as an in-memory column store database system.