Use DescribeKey with an AWS SDK or CLI

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

    /// <summary>
    /// Retrieve information about an AWS Key Management Service (AWS KMS) key.
    /// You can supply either the key Id or the key Amazon Resource Name (ARN)
    /// to the DescribeKeyRequest KeyId property.
    /// </summary>
    public class DescribeKey
    {
        public static async Task Main()
        {
            var keyId = "7c9eccc2-38cb-4c4f-9db3-766ee8dd3ad4";
            var request = new DescribeKeyRequest
            {
                KeyId = keyId,
            };

            var client = new AmazonKeyManagementServiceClient();

            var response = await client.DescribeKeyAsync(request);
            var metadata = response.KeyMetadata;

            Console.WriteLine($"{metadata.KeyId} created on: {metadata.CreationDate}");
            Console.WriteLine($"State: {metadata.KeyState}");
            Console.WriteLine($"{metadata.Description}");
        }
    }

Example 1: To find detailed information about a KMS key

The following describe-key example gets detailed information about the AWS managed key for Amazon S3 in the example account and Region. You can use this command to find details about AWS managed keys and customer managed keys.

To specify the KMS key, use the key-id parameter. This example uses an alias name value, but you can use a key ID, key ARN, alias name, or alias ARN in this command.

aws kms describe-key \
    --key-id alias/aws/s3

Output:

{
    "KeyMetadata": {
        "AWSAccountId": "846764612917",
        "KeyId": "b8a9477d-836c-491f-857e-07937918959b",
        "Arn": "arn:aws:kms:us-west-2:846764612917:key/b8a9477d-836c-491f-857e-07937918959b",
        "CreationDate": 2017-06-30T21:44:32.140000+00:00,
        "Enabled": true,
        "Description": "Default KMS key that protects my S3 objects when no other key is defined",
        "KeyUsage": "ENCRYPT_DECRYPT",
        "KeyState": "Enabled",
        "Origin": "AWS_KMS",
        "KeyManager": "AWS",
        "CustomerMasterKeySpec": "SYMMETRIC_DEFAULT",
        "EncryptionAlgorithms": [
            "SYMMETRIC_DEFAULT"
        ]
    }
}

For more information, see Viewing keys in the AWS Key Management Service Developer Guide.

Example 2: To get details about an RSA asymmetric KMS key

The following describe-key example gets detailed information about an asymmetric RSA KMS key used for signing and verification.

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

Output:

{
    "KeyMetadata": {
        "AWSAccountId": "111122223333",
        "KeyId": "1234abcd-12ab-34cd-56ef-1234567890ab",
        "Arn": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab",
        "CreationDate": "2019-12-02T19:47:14.861000+00:00",
        "CustomerMasterKeySpec": "RSA_2048",
        "Enabled": false,
        "Description": "",
        "KeyState": "Disabled",
        "Origin": "AWS_KMS",
        "MultiRegion": false,
        "KeyManager": "CUSTOMER",
        "KeySpec": "RSA_2048",
        "KeyUsage": "SIGN_VERIFY",
        "SigningAlgorithms": [
            "RSASSA_PKCS1_V1_5_SHA_256",
            "RSASSA_PKCS1_V1_5_SHA_384",
            "RSASSA_PKCS1_V1_5_SHA_512",
            "RSASSA_PSS_SHA_256",
            "RSASSA_PSS_SHA_384",
            "RSASSA_PSS_SHA_512"
        ]
    }
}

Example 3: To get details about a multi-Region replica key

The following describe-key example gets metadata for a multi-Region replica key. This multi-Region key is a symmetric encryption key. The output of a describe-key command for any multi-Region key returns information about the primary key and all of its replicas.

aws kms describe-key \
    --key-id arn:aws:kms:ap-northeast-1:111122223333:key/mrk-1234abcd12ab34cd56ef1234567890ab

Output:

{
    "KeyMetadata": {
        "MultiRegion": true,
        "AWSAccountId": "111122223333",
        "Arn": "arn:aws:kms:ap-northeast-1:111122223333:key/mrk-1234abcd12ab34cd56ef1234567890ab",
        "CreationDate": "2021-06-28T21:09:16.114000+00:00",
        "Description": "",
        "Enabled": true,
        "KeyId": "mrk-1234abcd12ab34cd56ef1234567890ab",
        "KeyManager": "CUSTOMER",
        "KeyState": "Enabled",
        "KeyUsage": "ENCRYPT_DECRYPT",
        "Origin": "AWS_KMS",
        "CustomerMasterKeySpec": "SYMMETRIC_DEFAULT",
        "EncryptionAlgorithms": [
            "SYMMETRIC_DEFAULT"
        ],
        "MultiRegionConfiguration": {
            "MultiRegionKeyType": "PRIMARY",
            "PrimaryKey": {
                "Arn": "arn:aws:kms:us-west-2:111122223333:key/mrk-1234abcd12ab34cd56ef1234567890ab",
                "Region": "us-west-2"
            },
            "ReplicaKeys": [
                {
                    "Arn": "arn:aws:kms:eu-west-1:111122223333:key/mrk-1234abcd12ab34cd56ef1234567890ab",
                    "Region": "eu-west-1"
                },
                {
                    "Arn": "arn:aws:kms:ap-northeast-1:111122223333:key/mrk-1234abcd12ab34cd56ef1234567890ab",
                    "Region": "ap-northeast-1"
                },
                {
                    "Arn": "arn:aws:kms:sa-east-1:111122223333:key/mrk-1234abcd12ab34cd56ef1234567890ab",
                    "Region": "sa-east-1"
                }
            ]
        }
    }
}

Example 4: To get details about an HMAC KMS key

The following describe-key example gets detailed information about an HMAC KMS key.

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

Output:

{
    "KeyMetadata": {
        "AWSAccountId": "123456789012",
        "KeyId": "1234abcd-12ab-34cd-56ef-1234567890ab",
        "Arn": "arn:aws:kms:us-west-2:123456789012:key/1234abcd-12ab-34cd-56ef-1234567890ab",
        "CreationDate": "2022-04-03T22:23:10.194000+00:00",
        "Enabled": true,
        "Description": "Test key",
        "KeyUsage": "GENERATE_VERIFY_MAC",
        "KeyState": "Enabled",
        "Origin": "AWS_KMS",
        "KeyManager": "CUSTOMER",
        "CustomerMasterKeySpec": "HMAC_256",
        "MacAlgorithms": [
            "HMAC_SHA_256"
        ],
        "MultiRegion": false
    }
}

    /**
     * Asynchronously checks if a specified key is enabled.
     *
     * @param keyId the ID of the key to check
     * @return a {@link CompletableFuture} that, when completed, indicates whether the key is enabled or not
     *
     * @throws RuntimeException if an exception occurs while checking the key state
     */
    public CompletableFuture<Boolean> isKeyEnabledAsync(String keyId) {
        DescribeKeyRequest keyRequest = DescribeKeyRequest.builder()
            .keyId(keyId)
            .build();

        CompletableFuture<DescribeKeyResponse> responseFuture = getAsyncClient().describeKey(keyRequest);
        return responseFuture.whenComplete((resp, ex) -> {
            if (resp != null) {
                KeyState keyState = resp.keyMetadata().keyState();
                if (keyState == KeyState.ENABLED) {
                    logger.info("The key is enabled.");
                } else {
                    logger.info("The key is not enabled. Key state: {}", keyState);
                }
            } else {
                throw new RuntimeException(ex);
            }
        }).thenApply(resp -> resp.keyMetadata().keyState() == KeyState.ENABLED);
    }

suspend fun describeSpecifcKey(keyIdVal: String?) {
    val request =
        DescribeKeyRequest {
            keyId = keyIdVal
        }

    KmsClient { region = "us-west-2" }.use { kmsClient ->
        val response = kmsClient.describeKey(request)
        println("The key description is ${response.keyMetadata?.description}")
        println("The key ARN is ${response.keyMetadata?.arn}")
    }
}

    /***
     * @param string $keyId
     * @return array
     */
    public function describeKey(string $keyId)
    {
        try {
            $result = $this->client->describeKey([
                "KeyId" => $keyId,
            ]);
            return $result['KeyMetadata'];
        }catch(KmsException $caught){
            if($caught->getAwsErrorMessage() == "NotFoundException"){
                echo "The request was rejected because the specified entity or resource could not be found.\n";
            }
            throw $caught;
        }
    }

class KeyManager:
    def __init__(self, kms_client):
        self.kms_client = kms_client
        self.created_keys = []

    @classmethod
    def from_client(cls) -> "KeyManager":
        """
        Creates a KeyManager instance with a default KMS client.

        :return: An instance of KeyManager initialized with the default KMS client.
        """
        kms_client = boto3.client("kms")
        return cls(kms_client)


    def describe_key(self, key_id: str) -> dict[str, any]:
        """
        Describes a key.

        :param key_id: The ARN or ID of the key to describe.
        :return: Information about the key.
        """

        try:
            key = self.kms_client.describe_key(KeyId=key_id)["KeyMetadata"]
            return key
        except ClientError as err:
            logging.error(
                "Couldn't get key '%s'. Here's why: %s",
                key_id,
                err.response["Error"]["Message"],
            )
            raise