paws.security.identity (version 0.1.5)

kms_generate_data_key_without_plaintext: Generates a unique data key

Description

Generates a unique data key. This operation returns a data key that is encrypted under a customer master key (CMK) that you specify. GenerateDataKeyWithoutPlaintext is identical to GenerateDataKey except that returns only the encrypted copy of the data key.

Usage

kms_generate_data_key_without_plaintext(KeyId, EncryptionContext,
  KeySpec, NumberOfBytes, GrantTokens)

Arguments

KeyId

[required] The identifier of the 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.

EncryptionContext

A set of key-value pairs that represents additional authenticated data.

For more information, see Encryption Context in the AWS Key Management Service Developer Guide.

KeySpec

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.

NumberOfBytes

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.

GrantTokens

A list of grant tokens.

For more information, see Grant Tokens in the AWS Key Management Service Developer Guide.

Request syntax

svc$generate_data_key_without_plaintext(
  KeyId = "string",
  EncryptionContext = list(
    "string"
  ),
  KeySpec = "AES_256"|"AES_128",
  NumberOfBytes = 123,
  GrantTokens = list(
    "string"
  )
)

Details

Like GenerateDataKey, GenerateDataKeyWithoutPlaintext returns a unique data key for each request. The bytes in the key are not related to the caller or CMK that is used to encrypt 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.

The result of this operation varies with the key state of the CMK. For details, see How Key State Affects Use of a Customer Master Key in the AWS Key Management Service Developer Guide.

Examples

# 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).
# }
# NOT RUN {
svc$generate_data_key_without_plaintext(
  KeyId = "alias/ExampleAlias",
  KeySpec = "AES_256"
)
# }
# NOT RUN {
# }