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cloud.google.com·6h ago
Security
Trail of Bits Blog·17d ago·5 min read
Don't let TEEs break your MPC
TL;DR
Threshold signature schemes (TSS) enhance security in multi-party computation (MPC) by allowing parties to sign without holding the key. However, deploying TSS in trusted execution environments (TEEs) can introduce vulnerabilities if the untrusted host is not properly managed.
✦ Why It Matters
Ensure your TEE implementations are secure by incorporating strong attestation processes today.
Key Takeaways
- Ensure TEE attestation is comprehensive and includes all critical components.
- Bind attestation to the identities of MPC parties for enhanced security.
- Terminate peer-to-peer communications inside TEEs to prevent tampering.
- Regularly verify the integrity of the TEE's execution environment.
How It Works
TEEs provide a secure area within a processor that protects code and data from unauthorized access. They ensure confidentiality by encrypting data in memory, integrity by preventing tampering, and attestation by allowing remote verification of the code running inside.
This is achieved through a process where the TEE generates cryptographic hashes of its software and configuration, which are then signed and can be verified by external parties.
⚠ The Catch
If the TEE's attestation process is incomplete or improperly verified, it can provide a false sense of security. For instance, if critical components are excluded from the attestation measurements, an attacker could modify those components without detection, undermining the entire security model.