AWS CLI Command Reference

[ aws . kms ]

verify

Description

Verifies a digital signature that was generated by the Sign operation.

Verification confirms that an authorized user signed the message with the specified KMS key and signing algorithm, and the message hasn’t changed since it was signed. If the signature is verified, the value of the SignatureValid field in the response is True . If the signature verification fails, the Verify operation fails with an KMSInvalidSignatureException exception.

A digital signature is generated by using the private key in an asymmetric KMS key. The signature is verified by using the public key in the same asymmetric KMS key. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide .

To use the Verify operation, specify the same asymmetric KMS key, message, and signing algorithm that were used to produce the signature. The message type does not need to be the same as the one used for signing, but it must indicate whether the value of the Message parameter should be hashed as part of the verification process.

You can also verify the digital signature by using the public key of the KMS key outside of KMS. Use the GetPublicKey operation to download the public key in the asymmetric KMS key and then use the public key to verify the signature outside of KMS. The advantage of using the Verify operation is that it is performed within KMS. As a result, it’s easy to call, the operation is performed within the FIPS boundary, it is logged in CloudTrail, and you can use key policy and IAM policy to determine who is authorized to use the KMS key to verify signatures.

To verify a signature outside of KMS with an SM2 public key (China Regions only), you must specify the distinguishing ID. By default, KMS uses 1234567812345678 as the distinguishing ID. For more information, see Offline verification with SM2 key pairs .

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:Verify (key policy)

Related operations : Sign

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

See also: AWS API Documentation

Synopsis

  verify
--key-id <value>
--message <value>
[--message-type <value>]
--signature <value>
--signing-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]

Options

--key-id (string)

Identifies the asymmetric KMS key that will be used to verify the signature. This must be the same KMS key that was used to generate the signature. If you specify a different KMS key, the signature verification fails.

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 .

--message (blob)

Specifies the message that was signed. You can submit a raw message of up to 4096 bytes, or a hash digest of the message. If you submit a digest, use the MessageType parameter with a value of DIGEST .

If the message specified here is different from the message that was signed, the signature verification fails. A message and its hash digest are considered to be the same message.

--message-type (string)

Tells KMS whether the value of the Message parameter should be hashed as part of the signing algorithm. Use RAW for unhashed messages; use DIGEST for message digests, which are already hashed.

When the value of MessageType is RAW , KMS uses the standard signing algorithm, which begins with a hash function. When the value is DIGEST , KMS skips the hashing step in the signing algorithm.

Warning

Use the DIGEST value only when the value of the Message parameter is a message digest. If you use the DIGEST value with an unhashed message, the security of the verification operation can be compromised.

When the value of MessageType is DIGEST , the length of the Message value must match the length of hashed messages for the specified signing algorithm.

You can submit a message digest and omit the MessageType or specify RAW so the digest is hashed again while signing. However, if the signed message is hashed once while signing, but twice while verifying, verification fails, even when the message hasn’t changed.

The hashing algorithm in that Verify uses is based on the SigningAlgorithm value.

  • Signing algorithms that end in SHA_256 use the SHA_256 hashing algorithm.
  • Signing algorithms that end in SHA_384 use the SHA_384 hashing algorithm.
  • Signing algorithms that end in SHA_512 use the SHA_512 hashing algorithm.
  • SM2DSA uses the SM3 hashing algorithm. For details, see Offline verification with SM2 key pairs .

Possible values:

  • RAW
  • DIGEST

--signature (blob)

The signature that the Sign operation generated.

--signing-algorithm (string)

The signing algorithm that was used to sign the message. If you submit a different algorithm, the signature verification fails.

Possible values:

  • RSASSA_PSS_SHA_256
  • RSASSA_PSS_SHA_384
  • RSASSA_PSS_SHA_512
  • RSASSA_PKCS1_V1_5_SHA_256
  • RSASSA_PKCS1_V1_5_SHA_384
  • RSASSA_PKCS1_V1_5_SHA_512
  • ECDSA_SHA_256
  • ECDSA_SHA_384
  • ECDSA_SHA_512
  • SM2DSA

--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 KMS API calls 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

--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.

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 .

To verify a digital signature

The following verify example verifies a cryptographic signature for a short, Base64-encoded message. The key ID, message, message type, and signing algorithm must be same ones that were used to sign the message. The signature that you specify cannot be base64-encoded. For help decoding the signature that the sign command returns, see the sign command examples.

The output of the command includes a Boolean SignatureValid field that indicates that the signature was verified. If the signature validation fails, the verify command fails, too.

Before running this command, replace the example key ID with a valid key ID from your AWS account.

aws kms verify \
    --key-id 1234abcd-12ab-34cd-56ef-1234567890ab \
    --message fileb://EncodedMessage \
    --message-type RAW \
    --signing-algorithm RSASSA_PKCS1_V1_5_SHA_256 \
    --signature fileb://ExampleSignature

Output:

{
    "KeyId": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab",
    "SignatureValid": true,
    "SigningAlgorithm": "RSASSA_PKCS1_V1_5_SHA_256"
}

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

Output

KeyId -> (string)

The Amazon Resource Name (key ARN ) of the asymmetric KMS key that was used to verify the signature.

SignatureValid -> (boolean)

A Boolean value that indicates whether the signature was verified. A value of True indicates that the Signature was produced by signing the Message with the specified KeyID and SigningAlgorithm. If the signature is not verified, the Verify operation fails with a KMSInvalidSignatureException exception.

SigningAlgorithm -> (string)

The signing algorithm that was used to verify the signature.
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