Trusted execution environment (TEE)

Chip makers build TEEs into processors under names such as Intel SGX and TDX, AMD SEV and Arm TrustZone. Code inside the enclave runs in encrypted memory, and the hardware can produce a remote attestation, a signed statement of exactly which program is running. Other parties can check that attestation before sending secrets or trusting the results.

In crypto, TEEs offer confidentiality and verifiability at near-normal speed. Privacy-focused chains use them to process encrypted smart contract state, block builders run inside them to protect transaction order flow, some rollups use them as an extra proof system, and wallet and custody services keep keys in them. They have become popular for AI agents that need to hold keys or show which model and code produced an action.

The trust shifts to the hardware vendor and its attestation service. Researchers have repeatedly broken enclaves through side-channel attacks, extracting keys from systems once considered secure, and physical access makes attacks easier. TEEs are usually combined with other safeguards rather than treated as proof on their own, and they are distinct from secure elements, the small chips in hardware wallets.