AWS CLI Command Reference

[ aws . kms ]

decapsulate¶

Description¶

Recovers the shared secret that was encapsulated with the public key of an ML-KEM KMS key. Module-Lattice-Based Key-Encapsulation Mechanism (ML-KEM), specified in FIPS 203 on the NIST website, is a post-quantum algorithm for establishing a shared secret between two parties. For an example of how two parties establish a shared secret over an insecure channel using ML-KEM, see ML-KEM keys in KMS in the Key Management Service Developer Guide .

The Decapsulate operation is not available in China Regions.

Decapsulate returns the shared secret as a 32-byte value. You can use it directly as key material, or run it through a key derivation function to derive multiple keys and nonces.

Warning

Decapsulate returns an InvalidCiphertextException when the length of the SharedSecretCiphertextBlob is inconsistent with the ML-KEM key spec. In all other cases, Decapsulate returns a 32-byte pseudo-random value. This is true even when the SharedSecretCiphertextBlob was created using a different ML-KEM key or altered from its original value. This behavior is a security feature called implicit rejection that helps protect against chosen-ciphertext attacks.

Because a response does not indicate that the ciphertext and key are valid, confirm the two parties derived the same shared secret before using it.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide .

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:Decapsulate (key policy)

Related operations:

  • Encapsulate
  • CreateKey
  • GetPublicKey
  • DescribeKey
Eventual consistency : The KMS API follows an eventual consistency model. For more information, see KMS eventual consistency .

See also: AWS API Documentation

Synopsis¶

  decapsulate
--key-id <value>
--shared-secret-ciphertext-blob <value>
--encapsulation-algorithm <value>
[--grant-tokens <value>]
[--dry-run | --no-dry-run]
[--cli-input-json | --cli-input-yaml]
[--generate-cli-skeleton <value>]
[--debug]
[--endpoint-url <value>]
[--no-verify-ssl]
[--no-paginate]
[--output <value>]
[--query <value>]
[--profile <value>]
[--region <value>]
[--version <value>]
[--color <value>]
[--no-sign-request]
[--ca-bundle <value>]
[--cli-read-timeout <value>]
[--cli-connect-timeout <value>]
[--cli-binary-format <value>]
[--no-cli-pager]
[--cli-auto-prompt]
[--no-cli-auto-prompt]
[--cli-error-format <value>]

Options¶

--key-id (string) [required]

Identifies the asymmetric ML-KEM KMS key whose public key was used to produce the encapsulated shared secret. KMS uses the private key in the specified key pair to decapsulate the shared secret.

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 .

Constraints:

  • min: 1
  • max: 2048

--shared-secret-ciphertext-blob (blob) [required]

The encapsulated (ciphertext) form of the shared secret to recover. This is the SharedSecretCiphertextBlob value that the Encapsulate operation returns. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.

Constraints:

  • min: 1
  • max: 6144

--encapsulation-algorithm (string) [required]

Specifies the key encapsulation algorithm used to recover the shared secret. The only valid value is ML_KEM .

Possible values:

  • ML_KEM

--grant-tokens (list)

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 .

Constraints:

  • min: 0
  • max: 10

(string)

Constraints:

  • min: 1
  • max: 8192

Syntax:

"string" "string" ...

--dry-run | --no-dry-run (boolean)

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your permissions in the Key Management Service Developer Guide .

--cli-input-json | --cli-input-yaml (string) Reads arguments from the JSON string provided. The JSON string follows the format provided by --generate-cli-skeleton. If other arguments are provided on the command line, those values will override the JSON-provided values. It is not possible to pass arbitrary binary values using a JSON-provided value as the string will be taken literally. This may not be specified along with --cli-input-yaml.

--generate-cli-skeleton (string) Prints a JSON skeleton to standard output without sending an API request. If provided with no value or the value input, prints a sample input JSON that can be used as an argument for --cli-input-json. Similarly, if provided yaml-input it will print a sample input YAML that can be used with --cli-input-yaml. If provided with the value output, it validates the command inputs and returns a sample output JSON for that command. The generated JSON skeleton is not stable between versions of the AWS CLI and there are no backwards compatibility guarantees in the JSON skeleton generated.

Global Options¶

--debug (boolean)

Turn on debug logging.

--endpoint-url (string)

Override command’s default URL with the given URL.

--no-verify-ssl (boolean)

By default, the AWS CLI uses SSL when communicating with AWS services. For each SSL connection, the AWS CLI will verify SSL certificates. This option overrides the default behavior of verifying SSL certificates.

--no-paginate (boolean)

Disable automatic pagination. If automatic pagination is disabled, the AWS CLI will only make one call, for the first page of results.

--output (string)

The formatting style for command output.

  • json
  • text
  • table
  • yaml
  • yaml-stream
  • off

--query (string)

A JMESPath query to use in filtering the response data.

--profile (string)

Use a specific profile from your credential file.

--region (string)

The region to use. Overrides config/env settings.

--version (string)

Display the version of this tool.

--color (string)

Turn on/off color output.

  • on
  • off
  • auto

--no-sign-request (boolean)

Do not sign requests. Credentials will not be loaded if this argument is provided.

--ca-bundle (string)

The CA certificate bundle to use when verifying SSL certificates. Overrides config/env settings.

--cli-read-timeout (int)

The maximum socket read time in seconds. If the value is set to 0, the socket read will be blocking and not timeout. The default value is 60 seconds.

--cli-connect-timeout (int)

The maximum socket connect time in seconds. If the value is set to 0, the socket connect will be blocking and not timeout. The default value is 60 seconds.

--cli-binary-format (string)

The formatting style to be used for binary blobs. The default format is base64. The base64 format expects binary blobs to be provided as a base64 encoded string. The raw-in-base64-out format preserves compatibility with AWS CLI V1 behavior and binary values must be passed literally. When providing contents from a file that map to a binary blob fileb:// will always be treated as binary and use the file contents directly regardless of the cli-binary-format setting. When using file:// the file contents will need to properly formatted for the configured cli-binary-format.

  • base64
  • raw-in-base64-out

--no-cli-pager (boolean)

Disable cli pager for output.

--cli-auto-prompt (boolean)

Automatically prompt for CLI input parameters.

--no-cli-auto-prompt (boolean)

Disable automatically prompt for CLI input parameters.

--cli-error-format (string)

The formatting style for error output. By default, errors are displayed in enhanced format.

  • legacy
  • json
  • yaml
  • text
  • table
  • enhanced

Output¶

KeyId -> (string)

The identifier of the ML-KEM KMS key used to decapsulate the shared secret.

Constraints:

  • min: 1
  • max: 2048

SharedSecret -> (blob)

The plaintext shared secret recovered from the encapsulated form. It is a 32-byte value that matches the shared secret held by the encapsulating party. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.

Constraints:

  • min: 1
  • max: 4096

EncapsulationAlgorithm -> (string)

The key encapsulation algorithm used to recover the shared secret.

Possible values:

  • ML_KEM
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