# Condition keys for Nitro Enclaves
<a name="conditions-nitro-enclave"></a>

The following condition keys are specific to Nitro Enclaves attestation:

## kms:RecipientAttestation:ImageSha384
<a name="conditions-kms-recipient-image-sha"></a>


| Amazon KMS Condition Keys | Condition Type | Value type | API Operations | Policy Type | 
| --- | --- | --- | --- | --- | 
| `kms:RecipientAttestation:ImageSha384` | String | Single-valued | `Decrypt`<br />`DeriveSharedSecret`<br />`GenerateDataKey`<br />`GenerateDataKeyPair`<br />`GenerateRandom` | Key policies and IAM policies | 

The `kms:RecipientAttestation:ImageSha384` condition key controls access to `Decrypt`, `DeriveSharedSecret`, `GenerateDataKey`, `GenerateDataKeyPair`, and `GenerateRandom` with a KMS key when the image digest from the signed attestation document in the request matches the value in the condition key. The `ImageSha384` value corresponds to PCR0 in the attestation document. This condition key is effective only when the `Recipient` parameter in the request specifies a signed attestation document for an Amazon Nitro enclave.

This value is also included in [CloudTrail events](ct-nitro-enclave.md) for requests to Amazon KMS for Nitro enclaves.

For example, the following key policy statement allows the `data-processing` role to use the KMS key for [Decrypt](https://docs.amazonaws.cn/kms/latest/APIReference/API_Decrypt.html), [DeriveSharedSecret](https://docs.amazonaws.cn/kms/latest/APIReference/API_DeriveSharedSecret), [GenerateDataKey](https://docs.amazonaws.cn/kms/latest/APIReference/API_GenerateDataKey.html), [GenerateDataKeyPair](https://docs.amazonaws.cn/kms/latest/APIReference/API_GenerateDataKeyPair.html), and [GenerateRandom](https://docs.amazonaws.cn/kms/latest/APIReference/API_GenerateRandom.html) operations. The `kms:RecipientAttestation:ImageSha384` condition key allows the operations only when the image digest value (PCR0) of the attestation document in the request matches the image digest value in the condition. This condition key is effective only when the `Recipient` parameter in the request specifies a signed attestation document for an Amazon Nitro enclave.

If the request does not include a valid attestation document from an Amazon Nitro enclave, permission is denied because this condition is not satisfied.

```
{
  "Sid" : "Enable enclave data processing",
  "Effect" : "Allow",
  "Principal" : {
    "AWS" : "arn:aws:iam::111122223333:role/data-processing"
  },
  "Action": [
    "kms:Decrypt",
    "kms:DeriveSharedSecret",
    "kms:GenerateDataKey",
    "kms:GenerateDataKeyPair",
    "kms:GenerateRandom"
  ],
  "Resource" : "*",
  "Condition": {
    "StringEqualsIgnoreCase": {
      "kms:RecipientAttestation:ImageSha384": "9fedcba8abcdef7abcdef6abcdef5abcdef4abcdef3abcdef2abcdef1abcdef1abcdef0abcdef1abcdef2abcdef3abcdef4abcdef5abcdef6abcdef7abcdef99"
    }
  }
}
```

## kms:RecipientAttestation:PCR<PCR\_ID>
<a name="conditions-kms-recipient-pcrs"></a>


| Amazon KMS Condition Keys | Condition Type | Value type | API Operations | Policy Type | 
| --- | --- | --- | --- | --- | 
| `kms:RecipientAttestation:PCR<PCR_ID>` | String | Single-valued | `Decrypt`<br />`DeriveSharedSecret`<br />`GenerateDataKey`<br />`GenerateDataKeyPair`<br />`GenerateRandom` | Key policies and IAM policies | 

The `kms:RecipientAttestation:PCR<PCR_ID>` condition key controls access to `Decrypt`, `DeriveSharedSecret`, `GenerateDataKey`, `GenerateDataKeyPair`, and `GenerateRandom` with a KMS key only when the platform configuration registers (PCRs) from the signed attestation document in the request match the PCRs in the condition key. This condition key is effective only when the `Recipient` parameter in the request specifies a signed attestation document from an Amazon Nitro enclave.

This value is also included in [CloudTrail events](ct-nitro-enclave.md) that represent requests to Amazon KMS for Nitro enclaves.

To specify a PCR value, use the following format. Concatenate the PCR ID to the condition key name. You can specify a PCR ID that identifies one of the [six enclave measurements](https://docs.amazonaws.cn/enclaves/latest/user/set-up-attestation.html#where) or a custom PCR ID that you defined for a specific use case. The PCR value must be a lower-case hexadecimal string of up to 96 bytes.

```
"kms:RecipientAttestation:PCR{{PCR_ID}}": "{{PCR_value}}"
```

For example, the following condition key specifies a particular value for PCR1, which corresponds to the hash of the kernel used for the enclave and the bootstrap process.

```
kms:RecipientAttestation:PCR1: "abc1abcdef2abcdef3abcdef4abcdef5abcdef6abcdef7abcdef8abcdef9abcdef8abcdef7abcdef6abcdef5abcdef4abcdef3abcdef2abcdef1abcdef0abcde"
```

The following example key policy statement allows the `data-processing` role to use the KMS key for the [Decrypt](https://docs.amazonaws.cn/kms/latest/APIReference/API_Decrypt.html) operation.

The `kms:RecipientAttestation:PCR` condition key in this statement allows the operation only when the PCR1 value in the signed attestation document in the request matches `kms:RecipientAttestation:PCR1` value in the condition. Use the `StringEqualsIgnoreCase` policy operator to require a case-insensitive comparison of the PCR values.

If the request does not include an attestation document, permission is denied because this condition is not satisfied.

```
{
  "Sid" : "Enable enclave data processing",
  "Effect" : "Allow",
  "Principal" : {
    "AWS" : "arn:aws:iam::111122223333:role/data-processing"
  },
  "Action": "kms:Decrypt",
  "Resource" : "*",
  "Condition": {
    "StringEqualsIgnoreCase": {
      "kms:RecipientAttestation:PCR1": "abc1de4f2dcf774f6e3b679f62e5f120065b2e408dcea327bd1c9dddaea6664e7af7935581474844767453082c6f1586116376cede396a30a39a611b9aad7966c87"
    }
  }
}
```