TEE Consensus Rollback Protection Using Ephemeral Identities

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Solution Overview

Problem

Existing consensus protocols relying on trusted execution environments (TEE) for rollback protection face limitations due to the scarcity and rate constraints of hardware monotonic counters, and reliance on third-party services is often unacceptable in practical use cases.

Innovation Solution

A method for rollback protection in TEE-based consensus systems that uses ephemeral identities generated and stored in volatile protected memory, cryptographically binding consensus messages to these identities, eliminating the need for hardware monotonic counters and third-party services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hardware monotonic counters are used for rollback protection in TEE-based consensus protocols, then message equivocation is prevented, but the system is limited by the scarcity and rate constraints of hardware monotonic counters

Engineering Contradiction:

Improverollback protectionVSAvoidavailability in cloud environments

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a software-based copy of the hardware monotonic counter functionality by generating ephemeral identities in volatile protected memory. This software implementation replicates the rollback protection mechanism without being constrained by hardware counter limitations, enabling deployment in cloud environments where hardware monotonic counters are unavailable or limited.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the hardware-based monotonic counter mechanism with a software-based ephemeral identity system. By substituting the physical hardware component with a software implementation that uses cryptographic binding and volatile protected memory, the system achieves the same security goals without the hardware constraints.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If third-party services are used for rollback protection, then identity management is simplified, but reliance on external services is unacceptable in many practical use cases

Engineering Contradiction:

Improveidentity managementVSAvoidindependence from third-party services

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent enables each TEE instance to autonomously generate and manage its own ephemeral identity without requiring external third-party services. The identity is created and stored within the volatile protected memory of the TEE itself, making the system self-sufficient and eliminating dependency on external identity management infrastructure.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The ephemeral identity is generated in advance during TEE initialization, before the consensus protocol begins. This preliminary creation of identity data eliminates the need for runtime registration or verification with third-party services, simplifying operations while maintaining independence.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If volatile protected memory is used to store ephemeral identities, then no hardware monotonic counters are needed, but the identities must be recreated after TEE restart

Engineering Contradiction:

Improvecompatibility with TEE platformsVSAvoididentity recreation time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The ephemeral identity is periodically regenerated each time the TEE restarts or is reinitialized. This periodic recreation ensures that the identity remains tied to the current TEE instance state, maintaining security while adapting to the volatile nature of the storage medium. The identity lifecycle aligns with the TEE operational cycles.

Inventive Principle:

Principle #19Periodic action

4Reliability

If ephemeral identities are cryptographically bound to consensus messages, then rollback protection is achieved, but communication overhead increases

Engineering Contradiction:

Improvemessage equivocation preventionVSAvoidmessage structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the ephemeral identity with the consensus message through cryptographic binding, merging the identity verification function directly into the message authentication process. This integration ensures that message validation inherently checks the sender's identity without requiring separate verification steps, reducing overall system complexity despite the increased message structure.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12470396B2Rollback protection with ephemeral identities for tee-based consensus protocols

Publication Date: 2025.11.11 NEC CORP

AI summary

A rollback protection method for preventing message equivocation in a consensus system is provided. The consensus system includes distributed computational nodes connected by a network and configured to run a TEE-based consensus protocol. The method includes: executing, within a trusted execution environment of a node of distributed computational nodes, a trusted component instance, that includes volatile protected memory with protected data stored therein and a protected piece of code implementing at least a part of a consensus algorithm, generating identity data comprising a unique ephemeral identity, and storing the identity data in the volatile protected memory of the trusted component instance, and certifying a message of the consensus algorithm, wherein a certified consensus algorithm message is generated by cryptographically binding parts of the consensus algorithm message to the unique ephemeral identity of the trusted component instance and at least parts of the protected data of the trusted component instance.