amazonka-kms-0.3.4: Amazon Key Management Service SDK.

Safe HaskellNone




Generates a data key that you can use in your application to locally encrypt data. This call returns a plaintext version of the key in the Plaintext field of the response object and an encrypted copy of the key in the CiphertextBlob field. The key is encrypted by using the master key specified by the KeyId field. To decrypt the encrypted key, pass it to the Decrypt API.

We recommend that you use the following pattern to locally encrypt data: call the GenerateDataKey API, use the key returned in the Plaintext response field to locally encrypt data, and then erase the plaintext data key from memory. Store the encrypted data key (contained in the CiphertextBlob field) alongside of the locally encrypted data.

You should not call the Encrypt function to re-encrypt your data keys within a region. GenerateDataKey always returns the data key encrypted and tied to the customer master key that will be used to decrypt it. There is no need to decrypt it twice. If you decide to use the optional EncryptionContext parameter, you must also store the context in full or at least store enough information along with the encrypted data to be able to reconstruct the context when submitting the ciphertext to the Decrypt API. It is a good practice to choose a context that you can reconstruct on the fly to better secure the ciphertext. For more information about how this parameter is used, see Encryption Context.

To decrypt data, pass the encrypted data key to the Decrypt API. Decrypt uses the associated master key to decrypt the encrypted data key and returns it as plaintext. Use the plaintext data key to locally decrypt your data and then erase the key from memory. You must specify the encryption context, if any, that you specified when you generated the key. The encryption context is logged by CloudTrail, and you can use this log to help track the use of particular data.



Request constructor



:: Text


-> GenerateDataKey 

GenerateDataKey constructor.

The fields accessible through corresponding lenses are:

Request lenses

gdkEncryptionContext :: Lens' GenerateDataKey (HashMap Text Text)

Name/value pair that contains additional data to be authenticated during the encryption and decryption processes that use the key. This value is logged by AWS CloudTrail to provide context around the data encrypted by the key.

gdkGrantTokens :: Lens' GenerateDataKey [Text]

For more information, see Grant Tokens.

gdkKeyId :: Lens' GenerateDataKey Text

A unique identifier for the customer master key. This value can be a globally unique identifier, a fully specified ARN to either an alias or a key, or an alias name prefixed by "alias/". Key ARN Example - arn:aws:kms:us-east-1:123456789012:key12345678-1234-1234-1234-123456789012 Alias ARN Example - arn:aws:kms:us-east-1:123456789012:alias/MyAliasName Globally Unique Key ID Example - 12345678-1234-1234-123456789012 Alias Name Example - alias/MyAliasName

gdkKeySpec :: Lens' GenerateDataKey (Maybe DataKeySpec)

Value that identifies the encryption algorithm and key size to generate a data key for. Currently this can be AES_128 or AES_256.

gdkNumberOfBytes :: Lens' GenerateDataKey (Maybe Natural)

Integer that contains the number of bytes to generate. Common values are 128, 256, 512, and 1024. 1024 is the current limit. We recommend that you use the KeySpec parameter instead.


Response constructor

generateDataKeyResponse :: GenerateDataKeyResponse

GenerateDataKeyResponse constructor.

The fields accessible through corresponding lenses are:

Response lenses

gdkrCiphertextBlob :: Lens' GenerateDataKeyResponse (Maybe Base64)

Ciphertext that contains the encrypted data key. You must store the blob and enough information to reconstruct the encryption context so that the data encrypted by using the key can later be decrypted. You must provide both the ciphertext blob and the encryption context to the Decrypt API to recover the plaintext data key and decrypt the object.

If you are using the CLI, the value is Base64 encoded. Otherwise, it is not encoded.

gdkrKeyId :: Lens' GenerateDataKeyResponse (Maybe Text)

System generated unique identifier of the key to be used to decrypt the encrypted copy of the data key.

gdkrPlaintext :: Lens' GenerateDataKeyResponse (Maybe Base64)

Plaintext that contains the data key. Use this for encryption and decryption and then remove it from memory as soon as possible.