| Copyright | (c) 2013-2021 Brendan Hay |
|---|---|
| License | Mozilla Public License, v. 2.0. |
| Maintainer | Brendan Hay <brendan.g.hay+amazonka@gmail.com> |
| Stability | auto-generated |
| Portability | non-portable (GHC extensions) |
| Safe Haskell | None |
Amazonka.KMS.GenerateDataKey
Description
Generates a unique symmetric data key for client-side encryption. This operation returns a plaintext copy of the data key and a copy that is encrypted under a KMS key that you specify. You can use the plaintext key to encrypt your data outside of KMS and store the encrypted data key with the encrypted data.
GenerateDataKey returns a unique data key for each request. The bytes
in the plaintext key are not related to the caller or the KMS key.
To generate a data key, specify the symmetric KMS key that will be used
to encrypt the data key. You cannot use an asymmetric KMS key to
generate data keys. To get the type of your KMS key, use the DescribeKey
operation. You must also specify the length of the data key. Use either
the KeySpec or NumberOfBytes parameters (but not both). For 128-bit
and 256-bit data keys, use the KeySpec parameter.
To get only an encrypted copy of the data key, use GenerateDataKeyWithoutPlaintext. To generate an asymmetric data key pair, use the GenerateDataKeyPair or GenerateDataKeyPairWithoutPlaintext operation. To get a cryptographically secure random byte string, use GenerateRandom.
You can use the 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.
Applications in Amazon Web Services Nitro Enclaves can call this operation by using the Amazon Web Services Nitro Enclaves Development Kit. For information about the supporting parameters, see How Amazon Web Services Nitro Enclaves use KMS 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 state: Effect on your KMS key in the Key Management Service Developer Guide.
How to use your data key
We recommend that you use the following pattern to encrypt data locally in your application. You can write your own code or use a client-side encryption library, such as the Amazon Web Services Encryption SDK, the Amazon DynamoDB Encryption Client, or Amazon S3 client-side encryption to do these tasks for you.
To encrypt data outside of KMS:
- Use the
GenerateDataKeyoperation to get a data key. - Use the plaintext data key (in the
Plaintextfield of the response) to encrypt your data outside of KMS. Then erase the plaintext data key from memory. - Store the encrypted data key (in the
CiphertextBlobfield of the response) with the encrypted data.
To decrypt data outside of KMS:
- Use the Decrypt operation to decrypt the encrypted data key. The operation returns a plaintext copy of the data key.
- Use the plaintext data key to decrypt data outside of KMS, then erase the plaintext data key from memory.
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:GenerateDataKey (key policy)
Related operations:
- Decrypt
- Encrypt
- GenerateDataKeyPair
- GenerateDataKeyPairWithoutPlaintext
- GenerateDataKeyWithoutPlaintext
Synopsis
- data GenerateDataKey = GenerateDataKey' {
- keySpec :: Maybe DataKeySpec
- encryptionContext :: Maybe (HashMap Text Text)
- numberOfBytes :: Maybe Natural
- grantTokens :: Maybe [Text]
- keyId :: Text
- newGenerateDataKey :: Text -> GenerateDataKey
- generateDataKey_keySpec :: Lens' GenerateDataKey (Maybe DataKeySpec)
- generateDataKey_encryptionContext :: Lens' GenerateDataKey (Maybe (HashMap Text Text))
- generateDataKey_numberOfBytes :: Lens' GenerateDataKey (Maybe Natural)
- generateDataKey_grantTokens :: Lens' GenerateDataKey (Maybe [Text])
- generateDataKey_keyId :: Lens' GenerateDataKey Text
- data GenerateDataKeyResponse = GenerateDataKeyResponse' {
- httpStatus :: Int
- keyId :: Text
- plaintext :: Sensitive Base64
- ciphertextBlob :: Base64
- newGenerateDataKeyResponse :: Int -> Text -> ByteString -> ByteString -> GenerateDataKeyResponse
- generateDataKeyResponse_httpStatus :: Lens' GenerateDataKeyResponse Int
- generateDataKeyResponse_keyId :: Lens' GenerateDataKeyResponse Text
- generateDataKeyResponse_plaintext :: Lens' GenerateDataKeyResponse ByteString
- generateDataKeyResponse_ciphertextBlob :: Lens' GenerateDataKeyResponse ByteString
Creating a Request
data GenerateDataKey Source #
See: newGenerateDataKey smart constructor.
Constructors
| GenerateDataKey' | |
Fields
| |
Instances
Arguments
| :: Text | |
| -> GenerateDataKey |
Create a value of GenerateDataKey with all optional fields omitted.
Use generic-lens or optics to modify other optional fields.
The following record fields are available, with the corresponding lenses provided for backwards compatibility:
$sel:keySpec:GenerateDataKey', generateDataKey_keySpec - Specifies the length of the data key. Use AES_128 to generate a
128-bit symmetric key, or AES_256 to generate a 256-bit symmetric key.
You must specify either the KeySpec or the NumberOfBytes parameter
(but not both) in every GenerateDataKey request.
$sel:encryptionContext:GenerateDataKey', generateDataKey_encryptionContext - Specifies the encryption context that will be used when encrypting the
data key.
An encryption context is a collection of non-secret key-value pairs that represents additional authenticated data. When you use an encryption context to encrypt data, you must specify the same (an exact case-sensitive match) encryption context to decrypt the data. An encryption context is optional when encrypting with a symmetric KMS key, but it is highly recommended.
For more information, see Encryption Context in the Key Management Service Developer Guide.
$sel:numberOfBytes:GenerateDataKey', generateDataKey_numberOfBytes - Specifies the length of the data key in bytes. For example, use the
value 64 to generate a 512-bit data key (64 bytes is 512 bits). For
128-bit (16-byte) and 256-bit (32-byte) data keys, use the KeySpec
parameter.
You must specify either the KeySpec or the NumberOfBytes parameter
(but not both) in every GenerateDataKey request.
$sel:grantTokens:GenerateDataKey', generateDataKey_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.
$sel:keyId:GenerateDataKey', generateDataKey_keyId - Identifies the symmetric KMS key that encrypts the data 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 "alias/". To specify a KMS
key in a different Amazon Web Services account, you must use the key ARN
or alias ARN.
For example:
- Key ID:
1234abcd-12ab-34cd-56ef-1234567890ab - Key ARN:
arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab - Alias name:
alias/ExampleAlias - Alias ARN:
arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias
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.
Request Lenses
generateDataKey_keySpec :: Lens' GenerateDataKey (Maybe DataKeySpec) Source #
Specifies the length of the data key. Use AES_128 to generate a
128-bit symmetric key, or AES_256 to generate a 256-bit symmetric key.
You must specify either the KeySpec or the NumberOfBytes parameter
(but not both) in every GenerateDataKey request.
generateDataKey_encryptionContext :: Lens' GenerateDataKey (Maybe (HashMap Text Text)) Source #
Specifies the encryption context that will be used when encrypting the data key.
An encryption context is a collection of non-secret key-value pairs that represents additional authenticated data. When you use an encryption context to encrypt data, you must specify the same (an exact case-sensitive match) encryption context to decrypt the data. An encryption context is optional when encrypting with a symmetric KMS key, but it is highly recommended.
For more information, see Encryption Context in the Key Management Service Developer Guide.
generateDataKey_numberOfBytes :: Lens' GenerateDataKey (Maybe Natural) Source #
Specifies the length of the data key in bytes. For example, use the
value 64 to generate a 512-bit data key (64 bytes is 512 bits). For
128-bit (16-byte) and 256-bit (32-byte) data keys, use the KeySpec
parameter.
You must specify either the KeySpec or the NumberOfBytes parameter
(but not both) in every GenerateDataKey request.
generateDataKey_grantTokens :: Lens' GenerateDataKey (Maybe [Text]) Source #
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.
generateDataKey_keyId :: Lens' GenerateDataKey Text Source #
Identifies the symmetric KMS key that encrypts the data 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 "alias/". To specify a KMS
key in a different Amazon Web Services account, you must use the key ARN
or alias ARN.
For example:
- Key ID:
1234abcd-12ab-34cd-56ef-1234567890ab - Key ARN:
arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab - Alias name:
alias/ExampleAlias - Alias ARN:
arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias
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.
Destructuring the Response
data GenerateDataKeyResponse Source #
See: newGenerateDataKeyResponse smart constructor.
Constructors
| GenerateDataKeyResponse' | |
Fields
| |
Instances
newGenerateDataKeyResponse Source #
Arguments
| :: Int | |
| -> Text | |
| -> ByteString | |
| -> ByteString | |
| -> GenerateDataKeyResponse |
Create a value of GenerateDataKeyResponse with all optional fields omitted.
Use generic-lens or optics to modify other optional fields.
The following record fields are available, with the corresponding lenses provided for backwards compatibility:
$sel:httpStatus:GenerateDataKeyResponse', generateDataKeyResponse_httpStatus - The response's http status code.
$sel:keyId:GenerateDataKey', generateDataKeyResponse_keyId - The Amazon Resource Name
(key ARN)
of the KMS key that encrypted the data key.
$sel:plaintext:GenerateDataKeyResponse', generateDataKeyResponse_plaintext - The plaintext data key. When you use the HTTP API or the Amazon Web
Services CLI, the value is Base64-encoded. Otherwise, it is not
Base64-encoded. Use this data key to encrypt your data outside of KMS.
Then, remove it from memory as soon as possible.--
-- Note: This Lens automatically encodes and decodes Base64 data.
-- The underlying isomorphism will encode to Base64 representation during
-- serialisation, and decode from Base64 representation during deserialisation.
-- This Lens accepts and returns only raw unencoded data.
$sel:ciphertextBlob:GenerateDataKeyResponse', generateDataKeyResponse_ciphertextBlob - The encrypted copy of the data key. When you use the HTTP API or the
Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is
not Base64-encoded.--
-- Note: This Lens automatically encodes and decodes Base64 data.
-- The underlying isomorphism will encode to Base64 representation during
-- serialisation, and decode from Base64 representation during deserialisation.
-- This Lens accepts and returns only raw unencoded data.
Response Lenses
generateDataKeyResponse_httpStatus :: Lens' GenerateDataKeyResponse Int Source #
The response's http status code.
generateDataKeyResponse_keyId :: Lens' GenerateDataKeyResponse Text Source #
The Amazon Resource Name (key ARN) of the KMS key that encrypted the data key.
generateDataKeyResponse_plaintext :: Lens' GenerateDataKeyResponse ByteString Source #
The plaintext data key. When you use the HTTP API or the Amazon Web
Services CLI, the value is Base64-encoded. Otherwise, it is not
Base64-encoded. Use this data key to encrypt your data outside of KMS.
Then, remove it from memory as soon as possible.--
-- Note: This Lens automatically encodes and decodes Base64 data.
-- The underlying isomorphism will encode to Base64 representation during
-- serialisation, and decode from Base64 representation during deserialisation.
-- This Lens accepts and returns only raw unencoded data.
generateDataKeyResponse_ciphertextBlob :: Lens' GenerateDataKeyResponse ByteString Source #
The encrypted copy of the data key. When you use the HTTP API or the
Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is
not Base64-encoded.--
-- Note: This Lens automatically encodes and decodes Base64 data.
-- The underlying isomorphism will encode to Base64 representation during
-- serialisation, and decode from Base64 representation during deserialisation.
-- This Lens accepts and returns only raw unencoded data.