Confidential Computing
How it works
Confidential computations run inside a hardware TEE instantiated on a CPU or GPU. TEE memory is hardware-encrypted, and the hardware enforces a trust boundary that defines the trusted computing base (TCB) — the set of elements able to access the data. A key element is remote cryptographic attestation: the environment presents a signed, verifiable attestation report proving it is genuine and running with an acceptable security posture; only after the relying party verifies it are data or keys released. Implementations differ in isolation level: virtual machine (e.g. Intel TDX, AMD SEV-SNP), application/process (e.g. Intel SGX), or function/library. The NVIDIA H100 was the first GPU to add hardware confidential computing for AI, establishing a chain of trust via secure boot, an SPDM session with the CPU TEE, and a signed attestation report; in CC-On mode GPU compute and HBM bandwidth are unchanged, while the encrypted CPU–GPU interconnect becomes the bottleneck.
Problem solved
Data being processed in a CPU/GPU and memory typically exists in a decrypted state and is exposed to inspection or tampering by privileged software (hypervisor, operating system) and by infrastructure administrators or the cloud provider. Encryption at rest and in transit does not protect data at this critical moment. Confidential computing closes this gap by protecting data and code during computation.
Components
A hardware-isolated environment on a CPU or GPU where code and data are protected from the rest of the system, including the operating system and hypervisor.
A cryptographic process in which the TEE presents signed, verifiable evidence of its authenticity and security state before it is given data or keys.
A hardware mechanism that encrypts the contents of memory assigned to the TEE, preventing plaintext reads from outside the enclave/VM.
The set of hardware, firmware and software elements able to access confidential data; the trust boundary defines what sits inside the TCB.
Implementation
Researchers have demonstrated architectural and side-channel attacks effective against TEEs, e.g. against Intel SGX and CIPHERLEAKS against AMD SEV-SNP.
In confidential mode on the H100, GPU compute and HBM bandwidth are unchanged, but the encrypted CPU–GPU interconnect limits bandwidth to about 4 GB/s.
Without correct attestation a compromised system can impersonate a trusted one; a large trusted computing base increases the attack surface.
Evolution
One of the first mainstream hardware TEEs, with application-level (enclave) isolation.
CCC formed under the Linux Foundation; founding premiere members: Alibaba, Arm, Google Cloud, Huawei, Intel, Microsoft, Red Hat. Standardized the term and definition.
Intel proposed Trust Domain Extensions (May 2021), isolating entire virtual machines from the hypervisor and host.
First GPU support for confidential computing, protecting data and code during AI training and inference.
Hyperparameters (configurable axes)
Granularity of isolation enforced by the TEE: virtual machine, application/process, or function/library. Determines the size of the trusted computing base.
Hardware requirements
CPU-based hardware TEEs (Intel SGX/TDX, AMD SEV-SNP, Arm CCA) are the foundation of confidential computing.
The NVIDIA H100 was the first GPU to add confidential computing for AI training and inference.