Use ListGrants with an Amazon SDK or CLI

    using System;
    using System.Threading.Tasks;
    using Amazon.KeyManagementService;
    using Amazon.KeyManagementService.Model;

    /// <summary>
    /// List the AWS Key Management Service (AWS KMS) grants that are associated with
    /// a specific key.
    /// </summary>
    public class ListGrants
    {
        public static async Task Main()
        {
            // The identifier of the AWS KMS key to disable. You can use the
            // key Id or the Amazon Resource Name (ARN) of the AWS KMS key.
            var keyId = "1234abcd-12ab-34cd-56ef-1234567890ab";
            var client = new AmazonKeyManagementServiceClient();
            var request = new ListGrantsRequest
            {
                KeyId = keyId,
            };

            var response = new ListGrantsResponse();

            do
            {
                response = await client.ListGrantsAsync(request);

                response.Grants.ForEach(grant =>
                {
                    Console.WriteLine($"{grant.GrantId}");
                });

                request.Marker = response.NextMarker;
            }
            while (response.Truncated);
        }
    }

To view the grants on an Amazon KMS key

The following list-grants example displays all of the grants on the specified Amazon managed KMS key for Amazon DynamoDB in your account. This grant allows DynamoDB to use the KMS key on your behalf to encrypt a DynamoDB table before writing it to disk. You can use a command like this one to view the grants on the Amazon managed KMS keys and customer managed KMS keys in the Amazon account and Region.

This command uses the key-id parameter with a key ID to identify the KMS key. You can use a key ID or key ARN to identify the KMS key. To get the key ID or key ARN of an Amazon managed KMS key, use the list-keys or list-aliases command.

aws kms list-grants \
    --key-id 1234abcd-12ab-34cd-56ef-1234567890ab

The output shows that the grant gives Amazon DynamoDB permission to use the KMS key for cryptographic operations, and gives it permission to view details about the KMS key (DescribeKey) and to retire grants (RetireGrant). The EncryptionContextSubset constraint limits these permission to requests that include the specified encryption context pairs. As a result, the permissions in the grant are effective only on specified account and DynamoDB table.

{
    "Grants": [
        {
            "Constraints": {
                "EncryptionContextSubset": {
                    "aws:dynamodb:subscriberId": "123456789012",
                    "aws:dynamodb:tableName": "Services"
                }
            },
            "IssuingAccount": "arn:aws:iam::123456789012:root",
            "Name": "8276b9a6-6cf0-46f1-b2f0-7993a7f8c89a",
            "Operations": [
                "Decrypt",
                "Encrypt",
                "GenerateDataKey",
                "ReEncryptFrom",
                "ReEncryptTo",
                "RetireGrant",
                "DescribeKey"
            ],
            "GrantId": "1667b97d27cf748cf05b487217dd4179526c949d14fb3903858e25193253fe59",
            "KeyId": "arn:aws:kms:us-west-2:123456789012:key/1234abcd-12ab-34cd-56ef-1234567890ab",
            "RetiringPrincipal": "dynamodb.us-west-2.amazonaws.com",
            "GranteePrincipal": "dynamodb.us-west-2.amazonaws.com",
            "CreationDate": "2021-05-13T18:32:45.144000+00:00"
        }
    ]
}

For more information, see Grants in Amazon KMS in the Amazon Key Management Service Developer Guide.

    /**
     * Asynchronously displays the grant IDs for the specified key ID.
     *
     * @param keyId the ID of the AWS KMS key for which to list the grants
     * @return a {@link CompletableFuture} that, when completed, will be null if the operation succeeded, or will throw a {@link RuntimeException} if the operation failed
     * @throws RuntimeException if there was an error listing the grants, either due to an {@link KmsException} or an unexpected error
     */
    public CompletableFuture<Object> displayGrantIdsAsync(String keyId) {
        ListGrantsRequest grantsRequest = ListGrantsRequest.builder()
            .keyId(keyId)
            .limit(15)
            .build();

        ListGrantsPublisher paginator = getAsyncClient().listGrantsPaginator(grantsRequest);
        return paginator.subscribe(response -> {
                response.grants().forEach(grant -> {
                    logger.info("The grant Id is: " + grant.grantId());
                });
            })
            .thenApply(v -> null)
            .exceptionally(ex -> {
                Throwable cause = ex.getCause();
                if (cause instanceof KmsException) {
                    throw new RuntimeException("Failed to list grants: " + cause.getMessage(), cause);
                } else {
                    throw new RuntimeException("An unexpected error occurred: " + cause.getMessage(), cause);
                }
            });
    }

suspend fun displayGrantIds(keyIdVal: String?) {
    val request =
        ListGrantsRequest {
            keyId = keyIdVal
            limit = 15
        }

    KmsClient { region = "us-west-2" }.use { kmsClient ->
        val response = kmsClient.listGrants(request)
        response.grants?.forEach { grant ->
            println("The grant Id is ${grant.grantId}")
        }
    }
}

class GrantManager:
    def __init__(self, kms_client):
        self.kms_client = kms_client


    def list_grants(self, key_id):
        """
        Lists grants for a key.

        :param key_id: The ARN or ID of the key to query.
        :return: The grants for the key.
        """
        answer = input(f"Ready to list grants on key {key_id} (y/n)? ")
        if answer.lower() == "y":
            try:
                grants = self.kms_client.list_grants(KeyId=key_id)["Grants"]
            except ClientError as err:
                logger.error(
                    "Couldn't list grants for key %s. Here's why: %s",
                    key_id,
                    err.response["Error"]["Message"],
                )
            else:
                print(f"Grants for key {key_id}:")
                pprint(grants)
                return grants