AWS CLI Command Reference

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[ aws . kms ]

verify-mac

Description

Verifies the hash-based message authentication code (HMAC) for a specified message, HMAC KMS key, and MAC algorithm. To verify the HMAC, VerifyMac computes an HMAC using the message, HMAC KMS key, and MAC algorithm that you specify, and compares the computed HMAC to the HMAC that you specify. If the HMACs are identical, the verification succeeds; otherwise, it fails. Verification indicates that the message hasn’t changed since the HMAC was calculated, and the specified key was used to generate and verify the HMAC.

HMAC KMS keys and the HMAC algorithms that KMS uses conform to industry standards defined in RFC 2104 .

This operation is part of KMS support for HMAC KMS keys. For details, see HMAC keys in 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 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:VerifyMac (key policy)

Related operations : GenerateMac

Eventual consistency : The KMS API follows an eventual consistency model. For more information, see KMS eventual consistency .

See also: AWS API Documentation

Synopsis

  verify-mac
--message <value>
--key-id <value>
--mac-algorithm <value>
--mac <value>
[--grant-tokens <value>]
[--dry-run | --no-dry-run]
[--cli-input-json <value>]
[--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>]

Options

--message (blob)

The message that will be used in the verification. Enter the same message that was used to generate the HMAC.

GenerateMac and VerifyMac do not provide special handling for message digests. If you generated an HMAC for a hash digest of a message, you must verify the HMAC for the same hash digest.

--key-id (string)

The KMS key that will be used in the verification.

Enter a key ID of the KMS key that was used to generate the HMAC. If you identify a different KMS key, the VerifyMac operation fails.

--mac-algorithm (string)

The MAC algorithm that will be used in the verification. Enter the same MAC algorithm that was used to compute the HMAC. This algorithm must be supported by the HMAC KMS key identified by the KeyId parameter.

Possible values:

  • HMAC_SHA_224
  • HMAC_SHA_256
  • HMAC_SHA_384
  • HMAC_SHA_512

--mac (blob)

The HMAC to verify. Enter the HMAC that was generated by the GenerateMac operation when you specified the same message, HMAC KMS key, and MAC algorithm as the values specified in this request.

--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 .

(string)

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 (string) Performs service operation based on the JSON string provided. The JSON string follows the format provided by --generate-cli-skeleton. If other arguments are provided on the command line, the CLI 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.

--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. If provided with the value output, it validates the command inputs and returns a sample output JSON for that command.

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

--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.

Examples

Note

To use the following examples, you must have the AWS CLI installed and configured. See the Getting started guide in the AWS CLI User Guide for more information.

Unless otherwise stated, all examples have unix-like quotation rules. These examples will need to be adapted to your terminal’s quoting rules. See Using quotation marks with strings in the AWS CLI User Guide .

Example 1: To verify an HMAC

The following verify-mac command verifies an HMAC for a particular message, HMAC KMS keys, and MAC algorithm. A value of ‘true’ in the MacValid value in the response indicates that the HMAC is valid.

In AWS CLI v2, the value of the message parameter must be Base64-encoded. Or, you can save the message in a file and use the fileb:// prefix, which tells the AWS CLI to read binary data from the file.

The MAC that you specify cannot be base64-encoded. For help decoding the MAC that the generate-mac command returns, see the generate-mac command examples.

Before running this command, replace the example key ID with a valid key ID from your AWS account. The key ID must represent a HMAC KMS key with a key usage of GENERATE_VERIFY_MAC.

msg=(echo 'Hello World' | base64)

aws kms verify-mac \
    --key-id 1234abcd-12ab-34cd-56ef-1234567890ab \
    --message fileb://Message \
    --mac-algorithm HMAC_SHA_384 \
    --mac fileb://ExampleMac

Output:

{
    "KeyId": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab",
    "MacValid": true,
    "MacAlgorithm": "HMAC_SHA_384"
}

For more information about using HMAC KMS keys in AWS KMS, see HMAC keys in AWS KMS in the AWS Key Management Service Developer Guide.

Output

KeyId -> (string)

The HMAC KMS key used in the verification.

MacValid -> (boolean)

A Boolean value that indicates whether the HMAC was verified. A value of True indicates that the HMAC (Mac ) was generated with the specified Message , HMAC KMS key (KeyID ) and MacAlgorithm. .

If the HMAC is not verified, the VerifyMac operation fails with a KMSInvalidMacException exception. This exception indicates that one or more of the inputs changed since the HMAC was computed.

MacAlgorithm -> (string)

The MAC algorithm used in the verification.