> ## Documentation Index
> Fetch the complete documentation index at: https://docs.phala.com/llms.txt
> Use this file to discover all available pages before exploring further.

> Reference guide for Intel TDX attestation quote fields and their meanings.

# Attestation Fields Reference

This reference explains each field in an Intel TDX attestation quote. Use this when you need to understand or verify specific measurements.

## Example Quote

Here's a typical attestation quote from Phala Cloud:

```json theme={"system"}
{
  "tee_tcb_svn": "06010300000000000000000000000000",
  "mr_seam": "5b38e33a6487958b72c3c12a938eaa5e3fd4510c51aeeab58c7d5ecee41d7c436489d6c8e4f92f160b7cad34207b00c1",
  "mr_signer_seam": "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "seam_attributes": "0000000000000000",
  "td_attributes": "0000001000000000",
  "xfam": "e702060000000000",
  "mr_td": "c68518a0ebb42136c12b2275164f8c72f25fa9a34392228687ed6e9caeb9c0f1dbd895e9cf475121c029dc47e70e91fd",
  "mr_config_id": "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "mr_owner": "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "mr_owner_config": "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "rt_mr0": "85e0855a6384fa1c8a6ab36d0dcbfaa11a5753e5a070c08218ae5fe872fcb86967fd2449c29e22e59dc9fec998cb6547",
  "rt_mr1": "9b43f9f34a64bc7191352585be0da1774a1499e698ba77cbf6184547d53d1770d6524c1cfa00b86352f273fc272a8cfe",
  "rt_mr2": "7cc2dadd5849bad220ab122c4fbf25a74dc91cc12702447d3b5cac0f49b2b139994f5cd936b293e5f0f14dea4262d668",
  "rt_mr3": "2c482b5b34f6902293bc203696f407241bfa319d2410a04c604d1021888d6028bf4bd280ff859ee270a0429aac5f0d82",
  "report_data": "afab9790acb13c4c651c1933a22b5f0663ef22927120dd08cc8291d7e0912d8b1c36eb75cf661a64735042f8e81bbe42cb9ab310ca95bf8d36c44cb8835c901f"
}
```

## Hardware Fields

### tee\_tcb\_svn

**Trusted Computing Base Security Version Number**

Security patch level for TEE hardware components. Verify this matches the latest version to ensure no known vulnerabilities.

### mr\_seam (MRSEAM)

**Measurement of TDX-Module**

Cryptographic hash of the SEAM (Secure Arbitration Mode) firmware. Confirms the TDX firmware hasn't been tampered with.

### mr\_td (MRTD)

**Measurement Register for Trust Domain**

Hash of the initial Trust Domain memory and configuration. Proves the TD was initialized with expected contents.

### seam\_attributes

**SEAM Firmware Attributes**

Configuration flags for SEAM firmware. Always zeros for Intel TDX.

### td\_attributes

**Trust Domain Attributes**

Configuration flags for the TD. Verifies the TD has expected security settings.

### xfam

**eXtended Feature Activation Mask**

Controls which CPU extended features are accessible to the TD. Ensures proper security boundaries.

## Runtime Measurement Registers (RTMRs)

These registers contain hash chains of boot components.

### RTMR0

**Virtual Hardware Measurement**

Measures the virtual hardware environment provided to the CVM.

### RTMR1

**Linux Kernel Measurement**

Hash of the Linux kernel loaded during boot.

### RTMR2

**Kernel Parameters Measurement**

Measurement of kernel command line and initrd.

### RTMR3

**Application Measurement**

dstack-specific measurements including:

* **app-id**: Relevant for KMS key derivation
* **compose-hash**: Hash of your Docker Compose configuration
* **instance-id**: Unique CVM instance identifier
* **key-provider**: Who distributed the root filesystem encryption keys

## RTMR3 Hash Chain

RTMR3 uses a hash chain mechanism:

```
RTMR3_new = SHA384(RTMR3_old || SHA384(event))
```

Each application component (compose-hash, instance-id, key-provider) is hashed individually, then chained together. Verify the final RTMR3 value using the [rtmr3-calculator](https://rtmr3-calculator.vercel.app/) tool.

## Application-Specific Fields

### report\_data (reportData)

**User-Provided Data (64 bytes)**

Custom data you attach to the quote. Common uses:

* **Public keys**: Bind a public key to prove you control the private key
* **Nonces**: Challenge-response protocols
* **Application state**: Hash of configuration or state

### mr\_config\_id, mr\_owner, mr\_owner\_config

**Configuration and Ownership**

Usually all zeros for dstack deployments. Reserved for advanced attestation scenarios.

## Which Fields Should I Verify?

Different verification levels require checking different fields:

**Quick Verification:**

* `report_data` - Your challenge or public key
* Use Cloud API for hardware verification

See [Quickstart](/phala-cloud/attestation/quickstart) for step-by-step guide.

**Application Verification:**

* `rt_mr3` (RTMR3) - Your compose-hash
* `report_data` - Custom data binding
* Use Cloud API for hardware and OS

See [Verify Your Application](/phala-cloud/attestation/verify-your-application) for complete guide.

**Complete Platform Verification:**

* `mr_td` (MRTD) - OS initial state
* `rt_mr0` through `rt_mr2` - OS boot chain
* `rt_mr3` (RTMR3) - Application and KMS binding
* `tee_tcb_svn` - Security patch level
* `mr_seam` - TDX firmware measurement

See [Verify the Platform](/phala-cloud/attestation/verify-the-platform) for complete guide.

**Security Audit:**

* All measurements above
* On-chain governance verification
* Reproducible OS builds
* KMS attestation

See [Complete Chain of Trust](/phala-cloud/attestation/chain-of-trust) for checklist.

## Resources

* **[dstack Attestation Guide](https://github.com/Dstack-TEE/dstack/blob/master/attestation.md)** - How dstack implements attestation
* **[Intel TDX Specification](https://www.intel.com/content/www/us/en/developer/articles/technical/intel-trust-domain-extensions.html)** - Official Intel documentation
* **[RTMR3 Calculator](https://rtmr3-calculator.vercel.app/)** - Verify RTMR3 values
* **[Verification Script](https://github.com/Dstack-TEE/dstack-examples/blob/main/attestation/rtmr3-based/verify.py)** - Example verification code

## Next Steps

<CardGroup cols={2}>
  <Card icon="rocket" href="/phala-cloud/attestation/quickstart" title="Quickstart" arrow="true">
    Verify your first quote
  </Card>

  <Card icon="code" href="/phala-cloud/attestation/verify-your-application" title="Verify Your Application" arrow="true">
    Prove your exact code is running
  </Card>

  <Card icon="server" href="/phala-cloud/attestation/verify-the-platform" title="Verify the Platform" arrow="true">
    Verify OS, KMS, and infrastructure
  </Card>

  <Card icon="list-check" href="/phala-cloud/attestation/chain-of-trust" title="Complete Security Checklist" arrow="true">
    Complete verification with no trust assumptions
  </Card>
</CardGroup>