Field Programmable Gate Array-Based Trusted Execution Environment for Blockchain Networks

Field Programmable Gate Array-Based Trusted Execution Environment for Blockchain Networks

Study Guide

Quiz

What advantages do Field Programmable Gate Arrays (FPGAs) provide in blockchain nodes?

What role does eFUSE play in the configuration of an FPGA-based Trusted Execution Environment (TEE)?

Describe the flow of information exchanged between the server and the FPGA device during the setup of an FPGA-based TEE.

Explain the significance of bitstream authentication in ensuring the security of an FPGA-based TEE.

How does the TEE setup ensure that the generated root private key is unique to a specific FPGA device?

How does the server verify that the FPGA device generated the correct root private key during the setup process?

What is the purpose of the deployed private key in the context of an FPGA-based TEE?

Describe the steps to handle an authentication request in an FPGA-based TEE.

Why is the security of data and code enhanced in the context of an FPGA-based TEE?

What are the security advantages of an FPGA-based TEE compared to a TEE that relies on an external entity?

Answer

FPGAs are able to provide a secure and tamper-proof environment, making them suitable for executing sensitive tasks such as blockchain contract virtual machines. Their hardware architecture provides higher security and performance compared to software-based solutions.

eFUSE is a one-time programmable area on the FPGA that is used to store device IDs, keys, and other sensitive information. Due to the nature of eFUSE, once programmed, the stored information is permanently fixed, preventing any tampering or unauthorized modification.

During the TEE setup process, the server programs the device information (device ID, device private key entropy, bitstream authentication key) into the eFUSE of the FPGA. It then sends an encrypted bitstream, which the FPGA decrypts and authenticates using the bitstream authentication key stored in the eFUSE. The decrypted bitstream contains the root private key entropy and a key generation module. The FPGA uses the root private key entropy, device ID, and device private key entropy to generate the root private key. The FPGA encrypts the message using the root private key and sends it to the server. The server decrypts the message using its own copy of the root private key, and if they match, the server encrypts the keys to be deployed and sends them back to the FPGA. The FPGA stores these keys for future use.

Bitstream authentication ensures that the bitstream loaded into the FPGA is authentic and has not been tampered with. This is achieved by verifying the origin and integrity of the bitstream using keys stored in a secure area of ​​the FPGA, such as eFUSE. This step prevents loading of malicious or compromised bitstreams, which could compromise the security of the TEE.

The root private key is generated locally on the FPGA device using a key generation module. The module uses the root private key entropy (embedded in the bitstream) along with the device ID and the device private key entropy stored in eFUSE. Since the device ID and device private key entropy are unique for each FPGA device, the generated root private key is unique even if the same bitstream is used.

After the root private key is generated, the FPGA device uses it to encrypt a message and sends the encrypted message to the server. The server decrypts the message using the root private key corresponding to the root private key entropy used to generate the FPGA root private key. If the server successfully decrypts the message, it indicates that the FPGA device has generated the correct root private key.

The deployed private key is used for secure communication between the FPGA-based TEE and the external environment. These keys can be used for a variety of purposes, such as decrypting future communications, digitally signing messages, or performing other cryptographic operations that require a higher level of security.

When an authentication request is received, the FPGA device encrypts a bitstream measurement report using the deployed private key and sends it to the requestor. The report contains information about the FPGA configuration, allowing the requestor to verify the authenticity of the TEE environment. The requestor can then decrypt the report using the corresponding public key known to be associated with the FPGA device.

In an FPGA-based TEE, data and code are physically isolated from the external environment. The FPGA hardware within the TEE provides a security boundary that prevents unauthorized access and modification. This isolation ensures that data and code remain secure even if the host operating system is compromised.

An FPGA-based TEE does not rely on the trust of an external entity such as Intel SGX. The elimination of this dependency enhances security because it eliminates the possibility of supply chain attacks or malicious behavior by external parties. An FPGA-based TEE provides a completely self-contained and independent trust environment, which is particularly important in security-critical applications.

Paper Questions

Discuss in detail the advantages and disadvantages of FPGA-based Trusted Execution Environments (TEEs) over traditional software-based TEEs.

Explain how FPGA-based TEEs can be used to protect data integrity and transaction privacy in blockchain networks.

Analyze different security challenges and considerations for implementing TEEs on FPGAs, with a special focus on key management, bitstream verification, and mitigations for side-channel attacks.

Explore potential use cases for using FPGA-based TEEs in consortium blockchain networks, focusing on their benefits in terms of enhanced security, scalability, and trust.

Compare and contrast FPGA-based TEEs with other hardware root-of-trust solutions, such as Trusted Platform Modules (TPMs) or secure enclaves, and evaluate their applicability in various blockchain scenarios.

Glossary

Term Definitions Field Programmable Gate Array (FPGA) An integrated circuit that can be configured for a specific application Trusted Execution Environment (TEE) A hardware environment that provides a secure enclave for code and data that executes on a host processor Blockchain A growing list of transaction records (blocks) that are cryptographically linked together Smart Contract A protocol for self-executing contracts that are stored and automatically executed on a blockchain eFUSE One-time programmable memory used to store sensitive information on an FPGA device Bitstream Configuration files used to configure FPGA functions Bitstream Authentication The process of verifying the authenticity and integrity of a bitstream Root Private Key A secret encryption key used to encrypt and decrypt other keys Encryption The process of converting information into an unintelligible code Digital Signature An electronic signature that ensures the authenticity of a digital message or document