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Secure Key Release Policy (SKR) Examples for Confidential Computing (ACC)

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SKR can only release exportable marked keys based on the Microsoft Azure Attestation (MAA) generated claims. There's a tight integration on the SKR policy definition to MAA claims. MAA claims by trusted execution environment (TEE) can be found here.

Follow the policy grammar for more examples on how you can customize the SKR policies.

Intel SGX Application Enclaves SKR policy examples

Example 1: Intel SGX based SKR policy validating the MR Signer (SGX enclave signer) details as part of the MAA claims


{
  "anyOf": [
    {
      "authority": "https://sharedeus2.eus2.attest.azure.net",
      "allOf": [
        {
          "claim": "x-ms-sgx-mrsigner",
          "equals": "9fa48b1629bd246a1de3d38fb7df97f6554cd65d6b3b72e85b86848ae6b578ba"
        }
      ]
    }
  ],
  "version": "1.0.0"
}

Example 2: Intel SGX based SKR policy validating the MR Signer (SGX enclave signer) or MR Enclave details as part of the MAA claims


{
  "anyOf": [
    {
      "authority": "https://sharedeus2.eus2.attest.azure.net",
      "allOf": [
        {
          "claim": "x-ms-sgx-mrsigner",
          "equals": "9fa48b1629bd246a1de3d38fb7df97f6554cd65d6b3b72e85b86848ae6b578ba"
        },
        {
          "claim": "x-ms-sgx-mrenclave",
          "equals": "9fa48b1629bg677jfsaawed7772e85b86848ae6b578ba"
        }
      ]
    }
  ],
  "version": "1.0.0"
}

Example 3: Intel SGX based SKR policy validating the MR Signer (SGX enclave signer) and MR Enclave with a min SVN number details as part of the MAA claims

{
  "anyOf": [
    {
      "authority": "https://sharedeus2.eus2.attest.azure.net",
      "allOf": [
        {
          "claim": "x-ms-sgx-mrsigner",
          "equals": "9fa48b1629bd246a1de3d38fb7df97f6554cd65d6b3b72e85b86848ae6b578ba"
        },
        {
          "claim": "x-ms-sgx-mrenclave",
          "equals": "9fa48b1629bg677jfsaawed7772e85b86848ae6b578ba"
        },
        {
          "claim": "x-ms-sgx-svn",
          "greater": 1
        }
      ]
    }
  ],
  "version": "1.0.0"
}

Confidential VM AMD SEV-SNP based VM TEE SKR policy examples

Example 1: A SKR policy that validates if this is Azure compliant CVM and is running on a genuine AMD SEV-SNP hardware and the MAA URL authority is spread across many regions.

{
    "version": "1.0.0",
    "anyOf": [
        {
            "authority": "https://sharedweu.weu.attest.azure.net",
            "allOf": [
                {
                    "claim": "x-ms-attestation-type",
                    "equals": "sevsnpvm"
                },
                {
                    "claim": "x-ms-compliance-status",
                    "equals": "azure-compliant-cvm"
                }
            ]
        },
        {
            "authority": "https://sharedeus2.weu2.attest.azure.net",
            "allOf": [
                {
                    "claim": "x-ms-attestation-type",
                    "equals": "sevsnpvm"
                },
                {
                    "claim": "x-ms-compliance-status",
                    "equals": "azure-compliant-cvm"
                }
            ]
        }
    ]
}

Example 2: A SKR policy that validates if the CVM is an Azure compliant CVM and is running on a genuine AMD SEV-SNP hardware and is of a known Virtual Machine ID. (VMIDs are unique across Azure)

{
  "version": "1.0.0",
  "allOf": [
    {
      "authority": "https://sharedweu.weu.attest.azure.net",
      "allOf": [
        {
          "claim": "x-ms-isolation-tee.x-ms-attestation-type",
          "equals": "sevsnpvm"
        },
        {
          "claim": "x-ms-isolation-tee.x-ms-compliance-status",
          "equals": "azure-compliant-cvm"
        },
        {
          "claim": "x-ms-azurevm-vmid",
          "equals": "B958DC88-E41D-47F1-8D20-E57B6B7E9825"
        }
      ]
    }
  ]
}

Confidential containers on Azure Container Instances (ACI) SKR policy examples

Example 1: Confidential containers on ACI validating the containers initiated and container configuration metadata as part of container group launch with added validations that this is an AMD SEV-SNP hardware.

Note

The containers metadata is a rego based policy hash reflected as in this example..

{
    "version": "1.0.0",
    "anyOf": [
        {
            "authority": "https://fabrikam1.wus.attest.azure.net",
            "allOf": [
                {
                    "claim": "x-ms-attestation-type",
                    "equals": "sevsnpvm"
                },
                {
                    "claim": "x-ms-compliance-status",
                    "equals": "azure-compliant-uvm"
                },
                {
                    "claim": "x-ms-sevsnpvm-hostdata",
                    "equals": "532eaabd9574880dbf76b9b8cc00832c20a6ec113d682299550d7a6e0f345e25"
                }
            ]
        }
    ]
}

References

Microsoft Azure Attestation (MAA)

Secure Key Release Concept and Basic Steps