Generates a random data key, which can be used to encrypt local data.
Usage notes
- Keys outside Key Management Service (KMS) instances: To perform cryptographic operations, use Alibaba Cloud SDK to call operations.
- Keys in KMS instances: To perform cryptographic operations, use one of the following methods:
- Method 1 (recommended): Use KMS Instance SDK to call KMS Instance API operations. For more information, see KMS Instance SDK and KMS Instance API.
- Method 2: Use Alibaba Cloud SDK to call operations. The authentication method supports only RAM roles whose trusted entities are Alibaba Cloud services. For more information, see Create a RAM role for a trusted Alibaba Cloud service.
QPS limits
You can call this operation up to 750 times per second per account. If the number of the calls per second exceeds the limit, throttling is triggered. As a result, your business may be affected. We recommend that you take note of the limit when you call this operation.
Description
This operation creates a random data key, encrypts the data key by using a key, and then returns the data key ciphertext. The GenerateDataKeyWithoutPlaintext operation provides exactly the same functionality as the GenerateDataKey operation. The only difference is that the GenerateDataKeyWithoutPlaintext operation does not return the data key plaintext.
The key that you specify in the request of this operation is used only to encrypt the data key and is not involved in the generation of the data key. KMS does not record or store the generated data key.
- This operation applies to the scenario when you do not need to use the data key to encrypt data immediately. Before you can use the data key to encrypt data, you must call the Decrypt operation to decrypt the data key ciphertext. Note
- This operation is also suitable for a distributed system with different trust levels. For example, a system stores data in different partitions based on a preset trust policy. A module of the system creates different partitions and generates different data keys for each partition. This module is not involved in data production and consumption after it completes the initialization of the control plane. This module is the key provider. When a module on the control plane produces and consumes data, the module obtains the data key ciphertext for each partition. After the module decrypts the data key ciphertext, the module uses the data key plaintext to encrypt or decrypt data and then deletes the data key plaintext from memory. In such a system, the key provider does not need to obtain the data key plaintext. It needs only to have the permissions to call the GenerateDataKeyWithoutPlaintext operation. The data producers or consumers do not need to generate new data keys. They need only to have the permissions to call the Decrypt operation.
Debugging
Request parameters
|
Parameter |
Type |
Required |
Example |
Description |
| Action | String | Yes | GenerateDataKeyWithoutPlaintext | The operation that you want to perform. Set the value to GenerateDataKeyWithoutPlaintext. |
| KeyId | String | Yes | 1234abcd-12ab-34cd-56ef-12345678**** | The ID of the key. The ID must be globally unique. You can also set this parameter to an alias that is bound to the key. For more information, see Alias overview. |
| KeySpec | String | No | AES_256 | The type of the data key. Valid values:
Note We recommend that you use KeySpec or NumberOfBytes to specify the length of a data key. If none of the parameters are specified, KMS generates a 256-bit data key. If both parameters are specified, KMS ignores KeySpec. |
| NumberOfBytes | Integer | No | 256 | The length of the data key. Valid values: 1 to 1024. Unit: bytes. |
| EncryptionContext | Map | No | {"Example":"Example"} | The JSON string that consists of key-value pairs. If you configure this parameter, an equivalent value is required when you call the Decrypt operation. For more information, see EncryptionContext. |
Response parameters
Parameter |
Type |
Example |
Description |
| KeyVersionId | String | 2ab1a983-7072-4bbc-a582-584b5bd8**** | The version ID of the key that is used to encrypt the plaintext. The primary version of the key is used. |
| KeyId | String | 599fa825-17de-417e-9554-bb032cc6**** | The ID of the key. The ID must be globally unique. Note If you set KeyId to an alias of the key, the ID of the key to which the alias is bound is returned. |
| CiphertextBlob | String | ODZhOWVmZDktM2QxNi00ODk0LWJkNGYtMWZjNDNmM2YyYWJmS7FmDBBQ0BkKsQrtRnidtPwirmDcS0ZuJCU41xxAAWk4Z8qsADfbV0b+i6kQmlvj79dJdGOvtX69Uycs901qOjop4bTS**** | The data key ciphertext that is encrypted by using the primary version of the key. |
| RequestId | String | 7021b6ec-4be7-4d3c-8a68-1e85d4d515a0 | The ID of the request. |
Examples
Sample requests
https://[Endpoint]/?Action=GenerateDataKeyWithoutPlaintext
&KeyId=1234abcd-12ab-34cd-56ef-12345678****
&<Common request parameters>Sample success responses
XML format
HTTP/1.1 200 OK
Content-Type:application/xml
<KMS>
<RequestId>7021b6ec-4be7-4d3c-8a68-1e85d4d515a0</RequestId>
<CiphertextBlob>ODZhOWVmZDktM2QxNi00ODk0LWJkNGYtMWZjNDNmM2YyYWJmS7FmDBBQ0BkKsQrtRnidtPwirmDcS0ZuJCU41xxAAWk4Z8qsADfbV0b+i6kQmlvj79dJdGOvtX69Uycs901qOjop4bTS****</CiphertextBlob>
<KeyId>599fa825-17de-417e-9554-bb032cc6****</KeyId>
<KeyVersionId>2ab1a983-7072-4bbc-a582-584b5bd8****</KeyVersionId>
</KMS>JSON format
HTTP/1.1 200 OK
Content-Type:application/json
{
"RequestId" : "7021b6ec-4be7-4d3c-8a68-1e85d4d515a0",
"CiphertextBlob" : "ODZhOWVmZDktM2QxNi00ODk0LWJkNGYtMWZjNDNmM2YyYWJmS7FmDBBQ0BkKsQrtRnidtPwirmDcS0ZuJCU41xxAAWk4Z8qsADfbV0b+i6kQmlvj79dJdGOvtX69Uycs901qOjop4bTS****",
"KeyId" : "599fa825-17de-417e-9554-bb032cc6****",
"KeyVersionId" : "2ab1a983-7072-4bbc-a582-584b5bd8****"
}Error codes
|
HTTP status code |
Error code |
Error message |
Description |
| 400 | InvalidParameter | The specified parameter is not valid. | The specified parameter is invalid. |
| 404 | Forbidden.KeyNotFound | The specified Key is not found. | The specified key does not exist. |
For a list of error codes, see Service error codes.