<a id="cli-aws-kms-generate-random"></a>

# generate-random

## Description

Returns a random byte string that is cryptographically secure.

You must use the `NumberOfBytes` parameter to specify the length of the random byte string. There is no default value for string length.

By default, the random byte string is generated in KMS. To generate the byte string in the CloudHSM cluster associated with an CloudHSM key store, use the `CustomKeyStoreId` parameter.

> `GenerateRandom` also supports [Amazon Web Services Nitro Enclaves](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/nitro-enclave.html) , which provide an isolated compute environment in Amazon EC2. To call `GenerateRandom` for a Nitro enclave or NitroTPM, use the [Amazon Web Services Nitro Enclaves SDK](https://docs.aws.amazon.com/enclaves/latest/user/developing-applications.html#sdk) or any Amazon Web Services SDK. Use the `Recipient` parameter to provide the attestation document for the attested environment. Instead of plaintext bytes, the response includes the plaintext bytes encrypted under the public key from the attestation document (`CiphertextForRecipient` ). For information about the interaction between KMS and Amazon Web Services Nitro Enclaves or Amazon Web Services NitroTPM, see [Cryptographic attestation support in KMS](https://docs.aws.amazon.com/kms/latest/developerguide/cryptographic-attestation.html) in the *Key Management Service Developer Guide* .

For more information about entropy and random number generation, see [Entropy and random number generation](https://docs.aws.amazon.com/kms/latest/developerguide/kms-cryptography.html#entropy-and-random-numbers) in the *Key Management Service Developer Guide* .

> **Cross-account use** : Not applicable. `GenerateRandom` does not use any account-specific resources, such as KMS keys.

> **Required permissions** : [kms:GenerateRandom](https://docs.aws.amazon.com/kms/latest/developerguide/kms-api-permissions-reference.html) (IAM policy)

> **Eventual consistency** : The KMS API follows an eventual consistency model. For more information, see [KMS eventual consistency](https://docs.aws.amazon.com/kms/latest/developerguide/accessing-kms.html#programming-eventual-consistency) .

See also: [AWS API Documentation](https://docs.aws.amazon.com/goto/WebAPI/kms-2014-11-01/GenerateRandom)

## Synopsis

```
  generate-random
[--number-of-bytes <value>]
[--custom-key-store-id <value>]
[--recipient <value>]
[--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

`--number-of-bytes` (integer)

> The length of the random byte string. This parameter is required.

> Constraints:

> * min: `1`
> * max: `1024`

`--custom-key-store-id` (string)

> Generates the random byte string in the CloudHSM cluster that is associated with the specified CloudHSM key store. To find the ID of a custom key store, use the  DescribeCustomKeyStores operation.

> External key store IDs are not valid for this parameter. If you specify the ID of an external key store, `GenerateRandom` throws an `UnsupportedOperationException` .

> Constraints:

> * min: `1`
> * max: `64`

`--recipient` (structure)

> A signed [attestation document](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/nitro-enclave-how.html#term-attestdoc) from an Amazon Web Services Nitro enclave or NitroTPM, and the encryption algorithm to use with the public key in the attestation document. The only valid encryption algorithm is `RSAES_OAEP_SHA_256` .

> This parameter supports the [Amazon Web Services Nitro Enclaves SDK](https://docs.aws.amazon.com/enclaves/latest/user/developing-applications.html#sdk) or any Amazon Web Services SDK for Amazon Web Services Nitro Enclaves. It supports any Amazon Web Services SDK for Amazon Web Services NitroTPM.

> When you use this parameter, instead of returning plaintext bytes, KMS encrypts the plaintext bytes under the public key in the attestation document, and returns the resulting ciphertext in the `CiphertextForRecipient` field in the response. This ciphertext can be decrypted only with the private key in the attested environment. The `Plaintext` field in the response is null or empty.

> For information about the interaction between KMS and Amazon Web Services Nitro Enclaves or Amazon Web Services NitroTPM, see [Cryptographic attestation support in KMS](https://docs.aws.amazon.com/kms/latest/developerguide/cryptographic-attestation.html) in the *Key Management Service Developer Guide* .

> KeyEncryptionAlgorithm -> (string)

> > The encryption algorithm that KMS should use with the public key for an Amazon Web Services Nitro Enclave or NitroTPM to encrypt plaintext values for the response. The only valid value is `RSAES_OAEP_SHA_256` .

> > Possible values:

> > * `RSAES_OAEP_SHA_256`

> AttestationDocument -> (blob)

> > The attestation document for an Amazon Web Services Nitro Enclave or a NitroTPM. This document includes the enclave’s public key.

> > Constraints:

> > * min: `1`
> > * max: `262144`

Shorthand Syntax:

```
KeyEncryptionAlgorithm=string,AttestationDocument=blob
```

JSON Syntax:

```json
{
  "KeyEncryptionAlgorithm": "RSAES_OAEP_SHA_256",
  "AttestationDocument": blob
}
```

`--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

## Examples

#### NOTE
To use the following examples, you must have the AWS CLI installed and configured. See the [Getting started guide](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html) 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](https://docs.aws.amazon.com/cli/latest/userguide/cli-usage-parameters-quoting-strings.html) in the *AWS CLI User Guide* .

**Example 1: To generate a 256-bit random byte string (Linux or macOs)**

The following `generate-random` example generates a 256-bit (32-byte), base64-encoded random byte string. The example decodes the byte string and saves it in the random file.

When you run this command, you must use the `number-of-bytes` parameter to specify the length of the random value in bytes.

You don’t specify a KMS key when you run this command. The random byte string is unrelated to any KMS key.

By default, AWS KMS generates the random number. However, if you specify a [custom key store](https://docs.aws.amazon.com/kms/latest/developerguide/keystore-cloudhsm.html), the random byte string is generated in the AWS CloudHSM cluster associated with the custom key store.

This example uses the following parameters and values:

* It uses the required `--number-of-bytes` parameter with a value of `32` to request a 32-byte (256-bit) string.
* It uses the `--output` parameter with a value of `text` to direct the AWS CLI to return the output as text, instead of JSON.
* It uses the `--query parameter` to extract the value of the `Plaintext` property from the response.
* It pipes ( | ) the output of the command to the `base64` utility, which decodes the extracted output.
* It uses the redirection operator ( > ) to save decoded byte string to the `ExampleRandom` file.
* It uses the redirection operator ( > ) to save the binary ciphertext to a file.
  ```bash
  aws kms generate-random \
      --number-of-bytes 32 \
      --output text \
      --query Plaintext | base64 --decode > ExampleRandom
  ```

This command produces no output.

For more information, see [AWS KMS cryptography essentials](https://docs.aws.amazon.com/kms/latest/developerguide/kms-cryptography.html#entropy-and-random-numbers) in the *AWS Key Management Service Developer Guide*.

**Example 2: To generate a 256-bit random number (Windows Command Prompt)**

The following `generate-random` example generates a 256-bit (32-byte), base64-encoded random byte string. The example decodes the byte string and saves it in the random file. This example is the same as the previous example, except that it uses the `certutil` utility in Windows to base64-decode the random byte string before saving it in a file.

First, generate a base64-encoded random byte string and saves it in a temporary file, `ExampleRandom.base64`.

```bash
aws kms generate-random \
    --number-of-bytes 32 \
    --output text \
    --query Plaintext > ExampleRandom.base64
```

This command produces no output. The output of the `generate-random` command is saved in a file.

Now use the `certutil -decode` command to decode the base64-encoded byte string in the `ExampleRandom.base64` file. Then, it saves the decoded byte string in the `ExampleRandom` file.

```
certutil -decode ExampleRandom.base64 ExampleRandom
```

Output:

```
Input Length = 18
Output Length = 12
CertUtil: -decode command completed successfully.
```

For more information, see [AWS KMS cryptography essentials](https://docs.aws.amazon.com/kms/latest/developerguide/kms-cryptography.html#entropy-and-random-numbers) in the *AWS Key Management Service Developer Guide*.

## Output

Plaintext -> (blob)

> The random byte string. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.

> If the response includes the `CiphertextForRecipient` field, the `Plaintext` field is null or empty.

> Constraints:

> * min: `1`
> * max: `4096`

CiphertextForRecipient -> (blob)

> The plaintext random bytes encrypted with the public key from the attestation document. This ciphertext can be decrypted only by using a private key from the attested environment.

> This field is included in the response only when the `Recipient` parameter in the request includes a valid attestation document from an Amazon Web Services Nitro enclave or NitroTPM. For information about the interaction between KMS and Amazon Web Services Nitro Enclaves or Amazon Web Services NitroTPM, see [Cryptographic attestation support in KMS](https://docs.aws.amazon.com/kms/latest/developerguide/cryptographic-attestation.html) in the *Key Management Service Developer Guide* .

> Constraints:

> * min: `1`
> * max: `6144`