Timestamp-Based Data Integrity in Untrusted Storage

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Solution Overview

Problem

Existing confidential computing systems face challenges in protecting data from tampering, particularly in untrusted storage environments, where replay attacks and incorrect data retrieval can occur.

Innovation Solution

The implementation of a confidential computing system that utilizes timestamps to prevent data tampering. This system includes a trusted data generator, a trusted data validator, a trusted timestamp generator, and trusted timestamp storage. The system generates a concatenated data object with metadata including a location indication and a timestamp, encrypts it, and stores it in untrusted storage while protecting the timestamp in trusted storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If data is stored in untrusted storage to enable flexible access, then storage versatility is improved, but data reliability deteriorates due to tampering risks

Engineering Contradiction:

Improvestorage accessibilityVSAvoiddata integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the data storage system into trusted and untrusted components. The data itself is stored in untrusted storage for accessibility, while separate timestamp metadata is stored in trusted storage to maintain integrity. This segmentation allows the system to leverage both untrusted storage flexibility and trusted storage reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces timestamps as an intermediary mechanism between the data and the storage system. These timestamps serve as proof of when data was written or modified, allowing verification of data integrity without requiring the storage system itself to be trusted. The timestamp acts as a mediator that bridges the gap between untrusted storage and trusted data verification.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If encryption is used to protect data in trusted execution environment, then data security is improved, but protection against replay attacks deteriorates

Engineering Contradiction:

Improvedata securityVSAvoidreplay attack vulnerability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by recording timestamps at the moment data is written to storage, before any potential replay attack can occur. These pre-recorded timestamps serve as temporal signatures that can later be verified to detect replay attempts. The timestamp is established in advance as a reference point for future validation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by verifying timestamps when data is retrieved from storage. The system compares the timestamp of retrieved data against expected or previously recorded timestamps to determine whether the data is legitimate or a replayed version. This feedback mechanism enables detection of replay attacks that would otherwise succeed despite encryption.

Inventive Principle:

Principle #23Feedback

3Reliability

If traditional trusted data implementations like Merkle Tree are used, then data validation capability is improved, but computational overhead increases

Engineering Contradiction:

Improvedata validationVSAvoidcomputational overhead

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent uses lightweight timestamp values instead of complex cryptographic hash structures like Merkle Trees. Timestamps are simple temporal indicators that require minimal computational resources to generate, store, and verify. This disposable approach trades the robustness of complex cryptographic structures for the efficiency of simple temporal markers that suffice for detecting replay attacks and validation errors.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS20250061234A1Using timestamps to prevent data tampering

Publication Date: 2025.02.20 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Timestamps are used to prevent data tampering. A trusted data generator generates a concatenated data object including a data object and metadata, which includes a location indication, a timestamp, and, depending on the type of encryption, an integrity value. The trusted timestamp generator encrypts the concatenated data object, stores the encrypted concatenated data object (e.g., in untrusted storage) in accordance with a location indicated by the location indication, and protects the timestamp in trusted storage (e.g., by protecting at least the root timestamp). A trusted data validator extracts the data object and metadata from the decrypted concatenated data object and validates the data object by comparing the storage location to the extracted location indication, the protected timestamp to the extracted timestamp, and a calculated integrity value to the extracted integrity value. Timestamps may be validated without calculations and with tolerances, supporting performance customization/security optimization.