AWS SDK Version 3 for .NET
API Reference

AWS services or capabilities described in AWS Documentation may vary by region/location. Click Getting Started with Amazon AWS to see specific differences applicable to the China (Beijing) Region.

Returns a unique asymmetric data key pair for use outside of KMS. This operation returns a plaintext public key and a copy of the private key that is encrypted under the symmetric encryption KMS key you specify. Unlike GenerateDataKeyPair, this operation does not return a plaintext private key. The bytes in the keys are random; they are not related to the caller or to the KMS key that is used to encrypt the private key.

You can use the public key that GenerateDataKeyPairWithoutPlaintext returns to encrypt data or verify a signature outside of KMS. Then, store the encrypted private key with the data. When you are ready to decrypt data or sign a message, you can use the Decrypt operation to decrypt the encrypted private key.

To generate a data key pair, you must specify a symmetric encryption KMS key to encrypt the private key in a data key pair. You cannot use an asymmetric KMS key or a KMS key in a custom key store. To get the type and origin of your KMS key, use the DescribeKey operation.

Use the KeyPairSpec parameter to choose an RSA or Elliptic Curve (ECC) data key pair. In China Regions, you can also choose an SM2 data key pair. KMS recommends that you use ECC key pairs for signing, and use RSA and SM2 key pairs for either encryption or signing, but not both. However, KMS cannot enforce any restrictions on the use of data key pairs outside of KMS.

GenerateDataKeyPairWithoutPlaintext returns a unique data key pair for each request. The bytes in the key are not related to the caller or KMS key that is used to encrypt the private key. The public key is a DER-encoded X.509 SubjectPublicKeyInfo, as specified in RFC 5280.

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

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:GenerateDataKeyPairWithoutPlaintext (key policy)

Related operations:

Note:

For .NET Core this operation is only available in asynchronous form. Please refer to GenerateDataKeyPairWithoutPlaintextAsync.

Namespace: Amazon.KeyManagementService
Assembly: AWSSDK.KeyManagementService.dll
Version: 3.x.y.z

Syntax

C#
public virtual GenerateDataKeyPairWithoutPlaintextResponse GenerateDataKeyPairWithoutPlaintext(
         GenerateDataKeyPairWithoutPlaintextRequest request
)
Parameters
request
Type: Amazon.KeyManagementService.Model.GenerateDataKeyPairWithoutPlaintextRequest

Container for the necessary parameters to execute the GenerateDataKeyPairWithoutPlaintext service method.

Return Value
The response from the GenerateDataKeyPairWithoutPlaintext service method, as returned by KeyManagementService.

Exceptions

ExceptionCondition
DependencyTimeoutException The system timed out while trying to fulfill the request. You can retry the request.
DisabledException The request was rejected because the specified KMS key is not enabled.
InvalidGrantTokenException The request was rejected because the specified grant token is not valid.
InvalidKeyUsageException The request was rejected for one of the following reasons: The KeyUsage value of the KMS key is incompatible with the API operation. The encryption algorithm or signing algorithm specified for the operation is incompatible with the type of key material in the KMS key (KeySpec). For encrypting, decrypting, re-encrypting, and generating data keys, the KeyUsage must be ENCRYPT_DECRYPT. For signing and verifying messages, the KeyUsage must be SIGN_VERIFY. For generating and verifying message authentication codes (MACs), the KeyUsage must be GENERATE_VERIFY_MAC. To find the KeyUsage of a KMS key, use the DescribeKey operation. To find the encryption or signing algorithms supported for a particular KMS key, use the DescribeKey operation.
KeyUnavailableException The request was rejected because the specified KMS key was not available. You can retry the request.
KMSInternalException The request was rejected because an internal exception occurred. The request can be retried.
KMSInvalidStateException The request was rejected because the state of the specified resource is not valid for this request. This exceptions means one of the following: The key state of the KMS key is not compatible with the operation. To find the key state, use the DescribeKey operation. For more information about which key states are compatible with each KMS operation, see Key states of KMS keys in the Key Management Service Developer Guide. For cryptographic operations on KMS keys in custom key stores, this exception represents a general failure with many possible causes. To identify the cause, see the error message that accompanies the exception.
NotFoundException The request was rejected because the specified entity or resource could not be found.
UnsupportedOperationException The request was rejected because a specified parameter is not supported or a specified resource is not valid for this operation.

Examples

This example returns an asymmetric elliptic curve (ECC) data key pair. The private key is encrypted under the symmetric encryption KMS key that you specify. This operation doesn't return a plaintext (unencrypted) private key.

To generate an asymmetric data key pair without a plaintext key


var client = new AmazonKeyManagementServiceClient();
var response = client.GenerateDataKeyPairWithoutPlaintext(new GenerateDataKeyPairWithoutPlaintextRequest 
{
    KeyId = "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab", // The symmetric encryption KMS key that encrypts the private key of the ECC data key pair.
    KeyPairSpec = "ECC_NIST_P521" // The requested key spec of the ECC asymmetric data key pair.
});

string keyId = response.KeyId; // The key ARN of the symmetric encryption KMS key that encrypted the private key in the ECC asymmetric data key pair.
string keyPairSpec = response.KeyPairSpec; // The actual key spec of the ECC asymmetric data key pair.
MemoryStream privateKeyCiphertextBlob = response.PrivateKeyCiphertextBlob; // The encrypted private key of the asymmetric ECC data key pair.
MemoryStream publicKey = response.PublicKey; // The public key (plaintext).

            

Version Information

.NET Framework:
Supported in: 4.5, 4.0, 3.5

See Also