This glossary defines key dstack terms—what they mean, why they matter, and how they’re used—organised A-Z with bold terms, italic highlights, and helpful links.

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A – C

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ACME (Automatic Certificate Management Environment)

Open IETF protocol (RFC 8555) that lets software request, renew, and revoke TLS certificates without human intervention.
In dstack: dstack-gateway calls Certbot in the DNS-01 flow so you can obtain a valid certificate even when ports 80/443 are fire-walled, guaranteeing “zero-touch” HTTPS for every app.

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ACME DNS-01 Challenge

Flow in which domain control is proven by publishing a TXT record under _acme-challenge.<domain>.
In dstack: used at first boot; the gateway automation injects the TXT record via your DNS provider’s API, then cleans it up after issuance.

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App-id

Unique identifier for deployed applications in dstack, typically derived from the application’s cryptographic hash.
In dstack: used for routing (<app-id>.domain.com), key derivation, and authorization checks with smart contracts.

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AppAuth

Ethereum smart-contract that stores the allowed container-image hash for a given application and signals the gateway that a CVM may expose traffic once its Attestation Quote matches that hash.
In dstack: every new deployment registers its image digest with AppAuth; the gateway consults this contract before adding a route.
Further reading: Smart-contract basics • dstack component map (GitHub).

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Attestation Quote

Signed report produced by a TEE (e.g. Intel TDX) that hashes each boot component (RTMR0-3) and binds them to a verifier-supplied nonce.
In dstack: dstack-guest-agent forwards the quote to dstack-kms; keys flow only when the measurements match the on-chain allow-list.

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Blockchain & Smart Contracts

Deterministic programs (e.g. KmsAuth, AppAuth) stored on a public chain. They record trusted hashes and decide whether a node, image, or user may receive keys.
In dstack: provide decentralised governance and an immutable audit trail—removing single points of failure typical in classical PKI.

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CAA Records (Certification Authority Authorization)

DNS records that specify which certificate authorities are allowed to issue certificates for a domain.
In dstack: automatically managed by the gateway to restrict certificate issuance and prevent unauthorized certificates.

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Certificate Transparency (CT)

Public log system (RFC 6962) for every certificate issued by participating CAs.
In dstack: the gateway subscribes to CT feeds and automatically revokes or alerts on rogue certs for your domains.

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Certbot

EFF-maintained ACME client that automates Let’s Encrypt operations.
In dstack: shipped inside the gateway image; runs on a timer to renew certs ~30 days before expiry without downtime.

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CID (Container ID)

Unique identifier for QEMU virtual machines in dstack, managed by the VMM’s allocation pool.
In dstack: prevents conflicts between VMs; configured via cid_start and cid_pool_size in VMM settings.

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Compose-hash

Cryptographic hash of the docker-compose.yml file content used for application verification.
In dstack: measured into RTMR registers and validated against blockchain records for secure deployments.

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Confidential Virtual Machine (CVM)

VM backed by a hardware TEE (Intel TDX today) providing automatic memory encryption and verifiable launch measurements.
In dstack: every user workload lives in a CVM so that the cloud operator, host OS, and hypervisor cannot read or tamper with data in use.

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Container Runtime

Minimal OCI runtime (runc / crun) inside the CVM image.
In dstack: obtains secrets through the guest-agent’s Unix socket rather than env-vars, reducing the attack surface for in-container code.

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D – F

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DCAP (Data-Center Attestation Primitives)

Intel open-source libraries for local verification of SGX / TDX quotes.
In dstack: bundled with KMS to avoid external Intel Attestation Service dependencies.
GitHub

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Device-id

Hardware-specific identifier used in attestation and authorization processes.
In dstack: helps ensure deployments run only on authorized hardware and prevents unauthorized migration.

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DNS TXT Record Lookup

Method for service discovery using DNS text records with the _dstack-app-address prefix.
In dstack: enables custom domain routing by publishing application endpoints in DNS records.

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Docker Compose

YAML file describing a multi-container app.
In dstack: your unchanged Compose file is parsed by the VMM; each service is mapped to a secure network endpoint.

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dstack CLI

Command-line interface for deploying and managing applications in dstack.
In dstack: primary user interface for deploy, list, stop operations and application lifecycle management.

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dstack-gateway

Security-aware reverse proxy: performs WireGuard ingress, RA-TLS validation, automatic certificate management, and CT monitoring.
Role: single public entry-point for all CVMs.

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dstack-guest-agent

Small Rust daemon inside every CVM. Exposes RPC for get_quote, get_key, and start_container.
Role: sole entity allowed to unseal keys, ensuring secrets never leave the encrypted memory domain.

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dstack-kms (Key Management Service)

CVM-resident service that uses DCAP to verify quotes, then deterministically derives per-app keys (disk, TLS, JWT) from a master seed.
Role: dstack’s root of cryptographic trust.

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dstack-os

Minimal, security-hardened Linux image (~40 MiB) built by meta-dstack, stripping out shells, compilers, and package managers to shrink the attack surface.
Benefit: identical runtime across TEE hardware and faster boot times.
Further reading: Phala blog • meta-dstack layer.

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dstack-util

Comprehensive command-line utility providing TDX attestation, system initialization, cryptographic services, and container management.
In dstack: handles full disk encryption setup, RTMR extensions, certificate generation, and system bootstrapping within CVMs.

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dstack-vmm (Virtual Machine Manager)

Rust supervisor on the host that spawns, monitors, and tears down CVMs via QEMU + TDX, and presents a REST/GUI that accepts your docker-compose.yaml.
Role: bridges DevOps tooling to hardware TEE features.

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FDE (Full-Disk Encryption)

Block-level encryption via Linux dm-crypt/LUKS.
In dstack: dstack-util setup seals the volume key so disks remain unreadable until the CVM passes attestation.

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G – M

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Gateway Agent

Service component within the gateway that handles communication with CVMs and manages WireGuard connections.
In dstack: configured on port 8090 by default and manages the VPN tunnel establishment.

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Guest Agent Socket (/var/run/dstack.sock)

Unix socket through which containers request keys or quotes.
Guarantee: secrets bypass the filesystem and environment variables, minimising leakage.

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Guest API

VMM endpoint (/guest) that provides proxied access to CVM guest agents.
In dstack: enables secure communication between host components and applications running inside CVMs.

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Hardware Random Number Generator (RNG)

On-die entropy source conforming to NIST SP 800-90.
In dstack: feeds all cryptographic operations inside the TEE; host RNGs are used only as a secondary pool.

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Host API

VMM endpoint (/api) for CVM notifications and host information exchange.
In dstack: handles communication between the host system and running CVMs for management operations.

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Instance-id

Unique identifier for specific CVM instances within an application deployment.
In dstack: used for tracking individual VM instances and managing their lifecycle and resources.

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Intel Trust Domain Extensions (TDX)

CPU feature set providing encrypted VM memory, DMA isolation, and a new attestation leaf.
In dstack: exclusive hardware backend for CVMs (AMD SEV-SNP & ARM CCA on the roadmap). See Intel TDX specification.

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iohash / RTMR Measurement

SHA-384 hash stored in TDX Runtime Measurement Registers.
In dstack: compared against the allow-list in KmsAuth before keys are released.

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KmsAuth

Smart-contract that keeps an allow-list of trusted RTMR hashes and authorises dstack-kms to release keys only when a presented quote matches one of those hashes.
In dstack: policy gate for every key-release request.
Further reading: Ethereum smart-contract docs • dstack README.

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LUKS (Linux Unified Key Setup)

Standard on-disk format for FDE keys; supports multiple keyslots and PBKDF2/Argon2 hardening.
In dstack: initialises NVMe drives attached to CVMs using AES-XTS-Plain64 cipher.

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meta-dstack

Yocto meta-layer that builds the dstack-os image with only the guest-agent, container runtime, and attestation libs.
Benefit: smaller footprint and reproducible builds.

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MRTD (Measurement of Runtime TDX Data)

CPU register that records a SHA-384 hash of the static TD state (e.g. firmware) at build time—complements dynamic RTMR0-3.
In dstack: dstack-kms and KmsAuth validate MRTD inside each quote.
See kernel.org TDX docs.

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N – R

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Nonce (Attestation)

Verifier-supplied random value inside the quote to guarantee freshness and stop replay attacks.
In dstack: the VMM generates a 256-bit nonce for every attestation request.

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OCI (Open Container Initiative)

Industry standard for container formats and runtimes.
In dstack: ensures compatibility with standard Docker containers while adding TEE security layers.

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Phala Cloud

Managed service that runs dstack on bare-metal TDX clusters, providing click-to-deploy CVMs, automatic upgrades, and usage-based billing—ideal for teams that want confidential computing without operating hardware.
Further reading: Phala docs • dstack architecture blog

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QEMU

Open-source machine emulator and virtualizer used by dstack-vmm to create and manage CVMs.
In dstack: provides the foundation for running CVMs with TDX support and hardware isolation.

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RA-TLS (Remote-Attestation TLS)

Technique (arXiv 1801.05863) of embedding a quote in an X.509 extension so the TLS handshake authenticates enclave state.
In dstack: the gateway proxies traffic only after validating this extension.

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ra-rpc

Wrapper around pRPC that tunnels every request through RA-TLS, giving internal API calls the same attestation guarantees as HTTPS.
In dstack: used by control-plane traffic (VMM ↔ KMS ↔ Guest Agent).

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Remote Attestation

Two-party protocol where a quote is generated and verified (using DCAP certs & CRLs).
In dstack: prerequisite for key release, network exposure, and service registration.

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Resource Allocation

Policy-driven distribution of CPU, RAM, and network to CVMs—enforced by cgroups and tc filters.
Goal: prevent noisy-neighbour issues while upholding TEE guarantees.

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RPC API

VMM endpoint (/prpc) for VM lifecycle management and operations using Protocol Buffers.
In dstack: primary interface for programmatic control of CVM deployment and management.

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RTMR (Runtime Measurement Registers)

TDX hardware registers (RTMR0-3) that store cryptographic measurements of system state and boot process.
In dstack: extended with application events and verified against blockchain allow-lists for security.

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S – Z

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Secure Ingress

Layered design: WireGuard tunnel → RA-TLS termination → service routing.
Outcome: traffic is encrypted on the WAN and remains cryptographically bound to the attested CVM on the LAN.

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SGX Sealing

Intel SGX feature for encrypting data with hardware-derived keys that persist across reboots.
In dstack: used in Local-Key-Provider mode for persistent key storage without external KMS dependency.

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Supervisor

Process management component that handles CVM lifecycle operations and resource monitoring.
In dstack: integrates with VMM to ensure reliable CVM startup, monitoring, and cleanup operations.

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TDX Module Specification

Official Intel document detailing TDX semantics—recommended starting point for low-level implementers.

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tdx-attest

Rust crate that talks to the TDX module to fetch quotes, extend RTMRs, and bundle them into RA-TLS certificates.
In dstack: compiled into the guest-agent so every CVM can self-serve attestation material.
GitHub: tdx-attestation-sdk

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TLS Passthrough

Gateway routing mode where TLS termination is handled by the application rather than the gateway.
In dstack: enabled by appending ‘s’ to domain names (<app-id>s.domain.com) for end-to-end encryption.

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TLS Termination

Gateway mode where HTTPS connections are decrypted at the gateway and forwarded as HTTP to applications.
In dstack: default mode for <app-id>.domain.com routing with automatic certificate management.

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Trusted Execution Environment (TEE)

Hardware-enforced enclave yielding confidentiality and integrity even against a malicious OS.
In dstack: foundational primitive—everything else is orchestration.
See GlobalPlatform TEE architecture.

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Web UI

VMM endpoint (/) providing HTML console for browser-based management of CVMs and applications.
In dstack: accessible at http://localhost:9080 for deployment monitoring and log viewing.

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WireGuard

Modern VPN protocol using Curve25519 + ChaCha20-Poly1305.
In dstack: links gateway replicas into an authenticated mesh and protects east-west traffic.
Whitepaper: WireGuard paper

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X25519

Elliptic curve Diffie-Hellman key agreement protocol using Curve25519.
In dstack: used for cryptographic key derivation and secure communication establishment.

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Zero Trust TLS

Security model where every connection is authenticated and encrypted regardless of network location.
In dstack: implemented through RA-TLS to ensure all communications are cryptographically bound to attested CVM state.

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Zero-Knowledge Proof (ZKP)

Cryptographic proof that reveals nothing except validity—enabling privacy-preserving audits.
Future use: optional layer for apps that must prove correct execution off-chain.

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ZFS

Advanced file system providing data integrity, snapshots, and encryption features.
In dstack: used with Blake3 checksums and encryption for secure data storage within CVMs.

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📑 Reference Index

Spec / Paper / RepoDescription
RFC 8555Automatic Certificate Management Environment
RFC 6962Certificate Transparency
Intel DCAP repogithub.com/intel/SGXDataCenterAttestationPrimitives
WireGuard Whitepaperwireguard.com/papers/wireguard.pdf
Intel TDX Specintel.com → Trust Domain Extensions
arXiv 1801.05863Integrating SGX Remote Attestation with TLS
LUKS FAQcryptsetup wiki
GlobalPlatform TEE SysArchglobalplatform.org specs
OCI Runtime Specopencontainers.org/about/overview/
dstack GitHubgithub.com/Dstack-TEE/dstack
Phala Networkphala.network