Trail of Bits warns of security risks when combining TEEs and MPC
Using Trusted Execution Environments (TEEs) to run Multi-Party Computation (MPC) protocols can introduce new vulnerabilities, such as host-driven rollback attacks, if not implemented with defense-in-depth.
Summary
Trail of Bits has published an analysis regarding the integration of Multi-Party Computation (MPC) within Trusted Execution Environments (TEEs). While TEEs can elevate semi-honest MPC protocols to provide malicious security guarantees through attestation, the untrusted host still controls critical operations like I/O and filesystem state. This can lead to attacks such as filesystem rollbacks that cause nonce reuse and private key exposure.
The tension between decentralized and centralized trust
- Trust Model Conflict: MPC distributes trust among multiple independent parties, whereas TEEs centralize trust in the hardware manufacturer.
- Host-Level Attacks: Even with TEE protection, the untrusted host manages memory management, CPU scheduling, and I/O, enabling rollback attacks.
- Rollback Vulnerability: A malicious host can revert the filesystem state to force a signer to reuse a nonce share, potentially disclosing private key shares.
- Attestation Requirements: Effective security requires verifying quote signatures, certificate chains, and matching measurements against known-good values via reproducible builds and binary transparency logs.
Why it matters
Developers implementing cryptographic protocols in hardware-secured environments must treat TEEs as a defense-in-depth layer rather than a total replacement for protocol-level security.
Original reference: blog.trailofbits.com →