Generates a unique symmetric data key. This operation returns a data key that is encrypted under a customer master key (CMK) that you specify. To request an asymmetric data key pair, use the GenerateDataKeyPair or GenerateDataKeyPairWithoutPlaintext operations.
kms_generate_data_key_without_plaintext(KeyId, EncryptionContext,
KeySpec, NumberOfBytes, GrantTokens)[required] The identifier of the symmetric customer master key (CMK) that encrypts the data key.
To specify a CMK, use its key ID, Amazon Resource Name (ARN), alias
name, or alias ARN. When using an alias name, prefix it with "alias/".
To specify a CMK in a different AWS 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 CMK, use ListKeys or DescribeKey. To get the alias name and alias ARN, use ListAliases.
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 CMK, but it is highly recommended.
For more information, see Encryption Context in the AWS Key Management Service Developer Guide.
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.
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 common key
lengths (128-bit and 256-bit symmetric keys), we recommend that you use
the KeySpec field instead of this one.
A list of grant tokens.
For more information, see Grant Tokens in the AWS Key Management Service Developer Guide.
svc$generate_data_key_without_plaintext(
KeyId = "string",
EncryptionContext = list(
"string"
),
KeySpec = "AES_256"|"AES_128",
NumberOfBytes = 123,
GrantTokens = list(
"string"
)
)
GenerateDataKeyWithoutPlaintext is identical to the GenerateDataKey
operation except that returns only the encrypted copy of the data key.
This operation is useful for systems that need to encrypt data at some
point, but not immediately. When you need to encrypt the data, you call
the Decrypt operation on the encrypted copy of the key.
It\'s also useful in distributed systems with different levels of trust. For example, you might store encrypted data in containers. One component of your system creates new containers and stores an encrypted data key with each container. Then, a different component puts the data into the containers. That component first decrypts the data key, uses the plaintext data key to encrypt data, puts the encrypted data into the container, and then destroys the plaintext data key. In this system, the component that creates the containers never sees the plaintext data key.
GenerateDataKeyWithoutPlaintext returns a unique data key for each
request. The bytes in the keys are not related to the caller or CMK that
is used to encrypt the private key.
To generate a data key, you must specify the symmetric customer master
key (CMK) that is used to encrypt the data key. You cannot use an
asymmetric CMK to generate a data key. To get the type of your CMK, use
the KeySpec field in the DescribeKey response. You must also specify
the length of the data key using either the KeySpec or NumberOfBytes
field (but not both). For common key lengths (128-bit and 256-bit
symmetric keys), use the KeySpec parameter.
If the operation succeeds, you will find the plaintext copy of the data
key in the Plaintext field of the response, and the encrypted copy of
the data key in the CiphertextBlob field.
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 AWS Key Management Service Developer Guide.
The CMK that you use for this operation must be in a compatible key state. For details, see How Key State Affects Use of a Customer Master Key in the AWS Key Management Service Developer Guide.
# NOT RUN {
# The following example generates an encrypted copy of a 256-bit symmetric
# data encryption key (data key). The data key is encrypted with the
# specified customer master key (CMK).
svc$generate_data_key_without_plaintext(
KeyId = "alias/ExampleAlias",
KeySpec = "AES_256"
)
# }
# NOT RUN {
# }
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