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, a plaintext private key, and a copy of the private key that is encrypted under the symmetric encryption KMS key you specify. You can use the data key pair to perform asymmetric cryptography and implement digital signatures outside of KMS. The bytes in the keys are random; they 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 GenerateDataKeyPair 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.

If you are using the data key pair to encrypt data, or for any operation where you don't immediately need a private key, consider using the GenerateDataKeyPairWithoutPlaintext operation. GenerateDataKeyPairWithoutPlaintext returns a plaintext public key and an encrypted private key, but omits the plaintext private key that you need only to decrypt ciphertext or sign a message. Later, when you need to decrypt the data or sign a message, use the Decrypt operation to decrypt the encrypted private key in the data key pair.

GenerateDataKeyPair returns a unique data key pair for each request. The bytes in the keys are random; they are not related to the caller or the 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. The private key is a DER-encoded PKCS8 PrivateKeyInfo, as specified in RFC 5958.

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:GenerateDataKeyPair (key policy)

Related operations:

Note:

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

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

Syntax

C#
public virtual GenerateDataKeyPairResponse GenerateDataKeyPair(
         GenerateDataKeyPairRequest request
)
Parameters
request
Type: Amazon.KeyManagementService.Model.GenerateDataKeyPairRequest

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

Return Value
The response from the GenerateDataKeyPair 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 generates an RSA data key pair for encryption and decryption. The operation returns a plaintext public key and private key, and a copy of the private key that is encrypted under a symmetric encryption KMS key that you specify.

To generate an RSA key pair for encryption and decryption


var client = new AmazonKeyManagementServiceClient();
var response = client.GenerateDataKeyPair(new GenerateDataKeyPairRequest 
{
    KeyId = "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab", // The key ID of the symmetric encryption KMS key that encrypts the private RSA key in the data key pair.
    KeyPairSpec = "RSA_3072" // The requested key spec of the RSA data key pair.
});

string keyId = response.KeyId; // The key ARN of the symmetric encryption KMS key that was used to encrypt the private key.
string keyPairSpec = response.KeyPairSpec; // The actual key spec of the RSA data key pair.
MemoryStream privateKeyCiphertextBlob = response.PrivateKeyCiphertextBlob; // The encrypted private key of the RSA data key pair.
MemoryStream privateKeyPlaintext = response.PrivateKeyPlaintext; // The plaintext private key of the RSA data key pair.
MemoryStream publicKey = response.PublicKey; // The public key (plaintext) of the RSA data key pair.

            

Version Information

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

See Also