Container for the parameters to the GetPublicKey operation.
Returns the public key of an asymmetric KMS key. Unlike the private key of a asymmetric
KMS key, which never leaves KMS unencrypted, callers with kms:GetPublicKey
permission can download the public key of an asymmetric KMS key. You can share the
public key to allow others to encrypt messages and verify signatures outside of KMS.
For information about asymmetric KMS keys, see Asymmetric
KMS keys in the Key Management Service Developer Guide.
You do not need to download the public key. Instead, you can use the public key within KMS by calling the Encrypt, ReEncrypt, or Verify operations with the identifier of an asymmetric KMS key. When you use the public key within KMS, you benefit from the authentication, authorization, and logging that are part of every KMS operation. You also reduce of risk of encrypting data that cannot be decrypted. These features are not effective outside of KMS.
To help you use the public key safely outside of KMS, GetPublicKey returns
important information about the public key in the response, including:
KeySpec: The type of key material in the public key, such as
RSA_4096orECC_NIST_P521.KeyUsage: Whether the key is used for encryption, signing, or deriving a shared secret.
EncryptionAlgorithms or SigningAlgorithms: A list of the encryption algorithms or the signing algorithms for the key.
Although KMS cannot enforce these restrictions on external operations, it is crucial that you use this information to prevent the public key from being used improperly. For example, you can prevent a public signing key from being used encrypt data, or prevent a public key from being used with an encryption algorithm that is not supported by KMS. You can also avoid errors, such as using the wrong signing algorithm in a verification operation.
To verify a signature outside of KMS with an SM2 public key (China Regions only),
you must specify the distinguishing ID. By default, KMS uses 1234567812345678
as the distinguishing ID. For more information, see Offline
verification with SM2 key pairs.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a different
Amazon Web Services account, specify the key ARN or alias ARN in the value of the
KeyId parameter.
Required permissions: kms:GetPublicKey (key policy)
Related operations: CreateKey
Eventual consistency: The KMS API follows an eventual consistency model. For more information, see KMS eventual consistency.
Inheritance Hierarchy
Amazon.Runtime.AmazonWebServiceRequest
Amazon.KeyManagementService.AmazonKeyManagementServiceRequest
Amazon.KeyManagementService.Model.GetPublicKeyRequest
Namespace: Amazon.KeyManagementService.Model
Assembly: AWSSDK.KeyManagementService.dll
Version: 3.x.y.z
Syntax
public class GetPublicKeyRequest : AmazonKeyManagementServiceRequest IAmazonWebServiceRequest
The GetPublicKeyRequest type exposes the following members
Constructors
| Name | Description | |
|---|---|---|
|
GetPublicKeyRequest() |
Properties
| Name | Type | Description | |
|---|---|---|---|
|
|
GrantTokens | System.Collections.Generic.List<System.String> |
Gets and sets the property GrantTokens. A list of grant tokens. Use a grant token when your permission to call this operation comes from a new grant that has not yet achieved eventual consistency. For more information, see Grant token and Using a grant token in the Key Management Service Developer Guide. |
|
|
KeyId | System.String |
Gets and sets the property KeyId. Identifies the asymmetric KMS key that includes the public key.
To specify a KMS key, use its key ID, key ARN, alias name, or alias ARN. When using
an alias name, prefix it with For example:
To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey. To get the alias name and alias ARN, use ListAliases. |
Examples
This example gets the public key of an asymmetric RSA KMS key used for encryption and decryption. The operation returns the key spec, key usage, and encryption or signing algorithms to help you use the public key correctly outside of AWS KMS.
To download the public key of an asymmetric KMS key
var client = new AmazonKeyManagementServiceClient();
var response = client.GetPublicKey(new GetPublicKeyRequest
{
KeyId = "arn:aws:kms:us-west-2:111122223333:key/0987dcba-09fe-87dc-65ba-ab0987654321" // The key ARN of the asymmetric KMS key.
});
string customerMasterKeySpec = response.CustomerMasterKeySpec; // The key spec of the asymmetric KMS key from which the public key was downloaded.
List<string> encryptionAlgorithms = response.EncryptionAlgorithms; // The encryption algorithms supported by the asymmetric KMS key that was downloaded.
string keyId = response.KeyId; // The key ARN of the asymmetric KMS key from which the public key was downloaded.
string keyUsage = response.KeyUsage; // The key usage of the asymmetric KMS key from which the public key was downloaded.
MemoryStream publicKey = response.PublicKey; // The public key (plaintext) of the asymmetric KMS key.
Version Information
.NET:
Supported in: 8.0 and newer, Core 3.1
.NET Standard:
Supported in: 2.0
.NET Framework:
Supported in: 4.5 and newer, 3.5