ExAws.KMS.Core

AWS Key Management Service

AWS Key Management Service

AWS Key Management Service (KMS) is an encryption and key management web service. This guide describes the KMS actions that you can call programmatically. For general information about KMS, see the AWS Key Management Service Developer Guide

Note: AWS provides SDKs that consist of libraries and sample code for various programming languages and platforms (Java, Ruby, .Net, iOS, Android, etc.). The SDKs provide a convenient way to create programmatic access to KMS and AWS. For example, the SDKs take care of tasks such as signing requests (see below), managing errors, and retrying requests automatically. For more information about the AWS SDKs, including how to download and install them, see Tools for Amazon Web Services. We recommend that you use the AWS SDKs to make programmatic API calls to KMS.

Clients must support TLS (Transport Layer Security) 1.0. We recommend TLS 1.2. Clients must also support cipher suites with Perfect Forward Secrecy (PFS) such as Ephemeral Diffie-Hellman (DHE) or Elliptic Curve Ephemeral Diffie-Hellman (ECDHE). Most modern systems such as Java 7 and later support these modes.

Signing Requests

Requests must be signed by using an access key ID and a secret access key. We strongly recommend that you do not use your AWS account access key ID and secret key for everyday work with KMS. Instead, use the access key ID and secret access key for an IAM user, or you can use the AWS Security Token Service to generate temporary security credentials that you can use to sign requests.

All KMS operations require Signature Version 4.

Recording API Requests

KMS supports AWS CloudTrail, a service that records AWS API calls and related events for your AWS account and delivers them to an Amazon S3 bucket that you specify. By using the information collected by CloudTrail, you can determine what requests were made to KMS, who made the request, when it was made, and so on. To learn more about CloudTrail, including how to turn it on and find your log files, see the AWS CloudTrail User Guide

Additional Resources

For more information about credentials and request signing, see the following:

Commonly Used APIs

Of the APIs discussed in this guide, the following will prove the most useful for most applications. You will likely perform actions other than these, such as creating keys and assigning policies, by using the console.

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Summary

create_alias!(client, input)

Same as create_alias/2 but raise on error

create_alias(client, input)

CreateAlias

create_grant!(client, input)

Same as create_grant/2 but raise on error

create_grant(client, input)

CreateGrant

create_key!(client, input)

Same as create_key/2 but raise on error

create_key(client, input)

CreateKey

decrypt!(client, input)

Same as decrypt/2 but raise on error

decrypt(client, input)

Decrypt

delete_alias!(client, input)

Same as delete_alias/2 but raise on error

delete_alias(client, input)

DeleteAlias

describe_key!(client, input)

Same as describe_key/2 but raise on error

describe_key(client, input)

DescribeKey

disable_key!(client, input)

Same as disable_key/2 but raise on error

disable_key(client, input)

DisableKey

disable_key_rotation!(client, input)

Same as disable_key_rotation/2 but raise on error

disable_key_rotation(client, input)

DisableKeyRotation

enable_key!(client, input)

Same as enable_key/2 but raise on error

enable_key(client, input)

EnableKey

enable_key_rotation!(client, input)

Same as enable_key_rotation/2 but raise on error

enable_key_rotation(client, input)

EnableKeyRotation

encrypt!(client, input)

Same as encrypt/2 but raise on error

encrypt(client, input)

Encrypt

generate_data_key!(client, input)

Same as generate_data_key/2 but raise on error

generate_data_key(client, input)

GenerateDataKey

generate_data_key_without_plaintext!(client, input)

Same as generate_data_key_without_plaintext/2 but raise on error

generate_data_key_without_plaintext(client, input)

GenerateDataKeyWithoutPlaintext

generate_random!(client, input)

Same as generate_random/2 but raise on error

generate_random(client, input)

GenerateRandom

get_key_policy!(client, input)

Same as get_key_policy/2 but raise on error

get_key_policy(client, input)

GetKeyPolicy

get_key_rotation_status!(client, input)

Same as get_key_rotation_status/2 but raise on error

get_key_rotation_status(client, input)

GetKeyRotationStatus

list_aliases!(client, input)

Same as list_aliases/2 but raise on error

list_aliases(client, input)

ListAliases

list_grants!(client, input)

Same as list_grants/2 but raise on error

list_grants(client, input)

ListGrants

list_key_policies!(client, input)

Same as list_key_policies/2 but raise on error

list_key_policies(client, input)

ListKeyPolicies

list_keys!(client, input)

Same as list_keys/2 but raise on error

list_keys(client, input)

ListKeys

put_key_policy!(client, input)

Same as put_key_policy/2 but raise on error

put_key_policy(client, input)

PutKeyPolicy

re_encrypt!(client, input)

Same as re_encrypt/2 but raise on error

re_encrypt(client, input)

ReEncrypt

retire_grant!(client, input)

Same as retire_grant/2 but raise on error

retire_grant(client, input)

RetireGrant

revoke_grant!(client, input)

Same as revoke_grant/2 but raise on error

revoke_grant(client, input)

RevokeGrant

update_alias!(client, input)

Same as update_alias/2 but raise on error

update_alias(client, input)

UpdateAlias

update_key_description!(client, input)

Same as update_key_description/2 but raise on error

update_key_description(client, input)

UpdateKeyDescription

Types

description_type :: binary

data_key_spec :: binary

list_grants_request :: [key_id: key_id_type, limit: limit_type, marker: marker_type]

re_encrypt_request :: [ciphertext_blob: ciphertext_type, destination_encryption_context: encryption_context_type, destination_key_id: key_id_type, grant_tokens: grant_token_list, source_encryption_context: encryption_context_type]

policy_name_type :: binary

retire_grant_request :: [grant_id: grant_id_type, grant_token: grant_token_type, key_id: key_id_type]

grant_token_type :: binary

generate_data_key_request :: [encryption_context: encryption_context_type, grant_tokens: grant_token_list, key_id: key_id_type, key_spec: data_key_spec, number_of_bytes: number_of_bytes_type]

grant_id_type :: binary

decrypt_response :: [key_id: key_id_type, plaintext: plaintext_type]

key_metadata :: [aws_account_id: aws_account_id_type, arn: arn_type, creation_date: date_type, description: description_type, enabled: boolean_type, key_id: key_id_type, key_usage: key_usage_type]

create_key_response :: [{:key_metadata, key_metadata}]

list_aliases_response :: [aliases: alias_list, next_marker: marker_type, truncated: boolean_type]

ciphertext_type :: binary

generate_data_key_without_plaintext_request :: [encryption_context: encryption_context_type, grant_tokens: grant_token_list, key_id: key_id_type, key_spec: data_key_spec, number_of_bytes: number_of_bytes_type]

generate_data_key_response :: [ciphertext_blob: ciphertext_type, key_id: key_id_type, plaintext: plaintext_type]

list_grants_response :: [grants: grant_list, next_marker: marker_type, truncated: boolean_type]

describe_key_response :: [{:key_metadata, key_metadata}]

grant_operation :: binary

list_key_policies_response :: [next_marker: marker_type, policy_names: policy_name_list, truncated: boolean_type]

encrypt_response :: [ciphertext_blob: ciphertext_type, key_id: key_id_type]

key_list_entry :: [key_arn: arn_type, key_id: key_id_type]

grant_constraints :: [encryption_context_equals: encryption_context_type, encryption_context_subset: encryption_context_type]

decrypt_request :: [ciphertext_blob: ciphertext_type, encryption_context: encryption_context_type, grant_tokens: grant_token_list]

get_key_rotation_status_response :: [{:key_rotation_enabled, boolean_type}]

key_id_type :: binary

limit_type :: integer

update_alias_request :: [alias_name: alias_name_type, target_key_id: key_id_type]

list_keys_response :: [keys: key_list, next_marker: marker_type, truncated: boolean_type]

re_encrypt_response :: [ciphertext_blob: ciphertext_type, key_id: key_id_type, source_key_id: key_id_type]

date_type :: integer

key_usage_type :: binary

grant_list_entry :: [constraints: grant_constraints, grant_id: grant_id_type, grantee_principal: principal_id_type, issuing_account: principal_id_type, operations: grant_operation_list, retiring_principal: principal_id_type]

boolean_type :: boolean

create_key_request :: [description: description_type, key_usage: key_usage_type, policy: policy_type]

create_grant_request :: [constraints: grant_constraints, grant_tokens: grant_token_list, grantee_principal: principal_id_type, key_id: key_id_type, operations: grant_operation_list, retiring_principal: principal_id_type]

create_alias_request :: [alias_name: alias_name_type, target_key_id: key_id_type]

arn_type :: binary

error_message_type :: binary

put_key_policy_request :: [key_id: key_id_type, policy: policy_type, policy_name: policy_name_type]

alias_name_type :: binary

alias_list_entry :: [alias_arn: arn_type, alias_name: alias_name_type, target_key_id: key_id_type]

marker_type :: binary

encrypt_request :: [encryption_context: encryption_context_type, grant_tokens: grant_token_list, key_id: key_id_type, plaintext: plaintext_type]

policy_type :: binary

principal_id_type :: binary

plaintext_type :: binary

Functions

create_alias(client, input)

Specs:

  • create_alias(client :: ExAws.KMS.t, input :: create_alias_request) :: ExAws.Request.JSON.response_t

CreateAlias

Creates a display name for a customer master key. An alias can be used to identify a key and should be unique. The console enforces a one-to-one mapping between the alias and a key. An alias name can contain only alphanumeric characters, forward slashes (/), underscores (_), and dashes (-). An alias must start with the word “alias” followed by a forward slash (alias/). An alias that begins with “aws” after the forward slash (alias/aws…) is reserved by Amazon Web Services (AWS).

To associate an alias with a different key, call UpdateAlias.

Note that you cannot create or update an alias that represents a key in another account.

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create_alias!(client, input)

Specs:

  • create_alias!(client :: ExAws.KMS.t, input :: create_alias_request) :: ExAws.Request.JSON.success_t | no_return

Same as create_alias/2 but raise on error.

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create_grant(client, input)

Specs:

  • create_grant(client :: ExAws.KMS.t, input :: create_grant_request) :: ExAws.Request.JSON.response_t

CreateGrant

Adds a grant to a key to specify who can access the key and under what conditions. Grants are alternate permission mechanisms to key policies. For more information about grants, see Grants in the developer guide. If a grant is absent, access to the key is evaluated based on IAM policies attached to the user.

  • ListGrants

  • RetireGrant

  • RevokeGrant
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create_grant!(client, input)

Specs:

  • create_grant!(client :: ExAws.KMS.t, input :: create_grant_request) :: ExAws.Request.JSON.success_t | no_return

Same as create_grant/2 but raise on error.

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create_key(client, input)

Specs:

  • create_key(client :: ExAws.KMS.t, input :: create_key_request) :: ExAws.Request.JSON.response_t

CreateKey

Creates a customer master key. Customer master keys can be used to encrypt small amounts of data (less than 4K) directly, but they are most commonly used to encrypt or envelope data keys that are then used to encrypt customer data. For more information about data keys, see GenerateDataKey and GenerateDataKeyWithoutPlaintext.

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create_key!(client, input)

Specs:

  • create_key!(client :: ExAws.KMS.t, input :: create_key_request) :: ExAws.Request.JSON.success_t | no_return

Same as create_key/2 but raise on error.

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decrypt(client, input)

Specs:

  • decrypt(client :: ExAws.KMS.t, input :: decrypt_request) :: ExAws.Request.JSON.response_t

Decrypt

Decrypts ciphertext. Ciphertext is plaintext that has been previously encrypted by using any of the following functions:

  • GenerateDataKey

  • GenerateDataKeyWithoutPlaintext

  • Encrypt

Note that if a caller has been granted access permissions to all keys (through, for example, IAM user policies that grant Decrypt permission on all resources), then ciphertext encrypted by using keys in other accounts where the key grants access to the caller can be decrypted. To remedy this, we recommend that you do not grant Decrypt access in an IAM user policy. Instead grant Decrypt access only in key policies. If you must grant Decrypt access in an IAM user policy, you should scope the resource to specific keys or to specific trusted accounts.

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decrypt!(client, input)

Specs:

  • decrypt!(client :: ExAws.KMS.t, input :: decrypt_request) :: ExAws.Request.JSON.success_t | no_return

Same as decrypt/2 but raise on error.

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delete_alias(client, input)

Specs:

  • delete_alias(client :: ExAws.KMS.t, input :: delete_alias_request) :: ExAws.Request.JSON.response_t

DeleteAlias

Deletes the specified alias. To associate an alias with a different key, call UpdateAlias.

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delete_alias!(client, input)

Specs:

  • delete_alias!(client :: ExAws.KMS.t, input :: delete_alias_request) :: ExAws.Request.JSON.success_t | no_return

Same as delete_alias/2 but raise on error.

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describe_key(client, input)

Specs:

  • describe_key(client :: ExAws.KMS.t, input :: describe_key_request) :: ExAws.Request.JSON.response_t

DescribeKey

Provides detailed information about the specified customer master key.

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describe_key!(client, input)

Specs:

  • describe_key!(client :: ExAws.KMS.t, input :: describe_key_request) :: ExAws.Request.JSON.success_t | no_return

Same as describe_key/2 but raise on error.

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disable_key(client, input)

Specs:

  • disable_key(client :: ExAws.KMS.t, input :: disable_key_request) :: ExAws.Request.JSON.response_t

DisableKey

Marks a key as disabled, thereby preventing its use.

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disable_key!(client, input)

Specs:

  • disable_key!(client :: ExAws.KMS.t, input :: disable_key_request) :: ExAws.Request.JSON.success_t | no_return

Same as disable_key/2 but raise on error.

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disable_key_rotation(client, input)

Specs:

DisableKeyRotation

Disables rotation of the specified key.

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disable_key_rotation!(client, input)

Specs:

Same as disable_key_rotation/2 but raise on error.

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enable_key(client, input)

Specs:

  • enable_key(client :: ExAws.KMS.t, input :: enable_key_request) :: ExAws.Request.JSON.response_t

EnableKey

Marks a key as enabled, thereby permitting its use. You can have up to 25 enabled keys at one time.

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enable_key!(client, input)

Specs:

  • enable_key!(client :: ExAws.KMS.t, input :: enable_key_request) :: ExAws.Request.JSON.success_t | no_return

Same as enable_key/2 but raise on error.

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enable_key_rotation(client, input)

Specs:

EnableKeyRotation

Enables rotation of the specified customer master key.

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enable_key_rotation!(client, input)

Specs:

Same as enable_key_rotation/2 but raise on error.

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encrypt(client, input)

Specs:

  • encrypt(client :: ExAws.KMS.t, input :: encrypt_request) :: ExAws.Request.JSON.response_t

Encrypt

Encrypts plaintext into ciphertext by using a customer master key. The Encrypt function has two primary use cases:

  • You can encrypt up to 4 KB of arbitrary data such as an RSA key, a database password, or other sensitive customer information.

  • If you are moving encrypted data from one region to another, you can use this API to encrypt in the new region the plaintext data key that was used to encrypt the data in the original region. This provides you with an encrypted copy of the data key that can be decrypted in the new region and used there to decrypt the encrypted data.

Unless you are moving encrypted data from one region to another, you don’t use this function to encrypt a generated data key within a region. You retrieve data keys already encrypted by calling the GenerateDataKey or GenerateDataKeyWithoutPlaintext function. Data keys don’t need to be encrypted again by calling Encrypt.

If you want to encrypt data locally in your application, you can use the GenerateDataKey function to return a plaintext data encryption key and a copy of the key encrypted under the customer master key (CMK) of your choosing.

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encrypt!(client, input)

Specs:

  • encrypt!(client :: ExAws.KMS.t, input :: encrypt_request) :: ExAws.Request.JSON.success_t | no_return

Same as encrypt/2 but raise on error.

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generate_data_key(client, input)

Specs:

GenerateDataKey

Generates a data key that you can use in your application to locally encrypt data. This call returns a plaintext version of the key in the Plaintext field of the response object and an encrypted copy of the key in the CiphertextBlob field. The key is encrypted by using the master key specified by the KeyId field. To decrypt the encrypted key, pass it to the Decrypt API.

We recommend that you use the following pattern to locally encrypt data: call the GenerateDataKey API, use the key returned in the Plaintext response field to locally encrypt data, and then erase the plaintext data key from memory. Store the encrypted data key (contained in the CiphertextBlob field) alongside of the locally encrypted data.

Note:You should not call the Encrypt function to re-encrypt your data keys within a region. GenerateDataKey always returns the data key encrypted and tied to the customer master key that will be used to decrypt it. There is no need to decrypt it twice. If you decide to use the optional EncryptionContext parameter, you must also store the context in full or at least store enough information along with the encrypted data to be able to reconstruct the context when submitting the ciphertext to the Decrypt API. It is a good practice to choose a context that you can reconstruct on the fly to better secure the ciphertext. For more information about how this parameter is used, see Encryption Context.

To decrypt data, pass the encrypted data key to the Decrypt API. Decrypt uses the associated master key to decrypt the encrypted data key and returns it as plaintext. Use the plaintext data key to locally decrypt your data and then erase the key from memory. You must specify the encryption context, if any, that you specified when you generated the key. The encryption context is logged by CloudTrail, and you can use this log to help track the use of particular data.

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generate_data_key!(client, input)

Specs:

Same as generate_data_key/2 but raise on error.

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generate_data_key_without_plaintext(client, input)

Specs:

GenerateDataKeyWithoutPlaintext

Returns a data key encrypted by a customer master key without the plaintext copy of that key. Otherwise, this API functions exactly like GenerateDataKey. You can use this API to, for example, satisfy an audit requirement that an encrypted key be made available without exposing the plaintext copy of that key.

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generate_data_key_without_plaintext!(client, input)

Specs:

Same as generate_data_key_without_plaintext/2 but raise on error.

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generate_random(client, input)

Specs:

GenerateRandom

Generates an unpredictable byte string.

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generate_random!(client, input)

Specs:

  • generate_random!(client :: ExAws.KMS.t, input :: generate_random_request) :: ExAws.Request.JSON.success_t | no_return

Same as generate_random/2 but raise on error.

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get_key_policy(client, input)

Specs:

GetKeyPolicy

Retrieves a policy attached to the specified key.

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get_key_policy!(client, input)

Specs:

  • get_key_policy!(client :: ExAws.KMS.t, input :: get_key_policy_request) :: ExAws.Request.JSON.success_t | no_return

Same as get_key_policy/2 but raise on error.

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get_key_rotation_status(client, input)

Specs:

GetKeyRotationStatus

Retrieves a Boolean value that indicates whether key rotation is enabled for the specified key.

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get_key_rotation_status!(client, input)

Specs:

Same as get_key_rotation_status/2 but raise on error.

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list_aliases(client, input)

Specs:

  • list_aliases(client :: ExAws.KMS.t, input :: list_aliases_request) :: ExAws.Request.JSON.response_t

ListAliases

Lists all of the key aliases in the account.

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list_aliases!(client, input)

Specs:

  • list_aliases!(client :: ExAws.KMS.t, input :: list_aliases_request) :: ExAws.Request.JSON.success_t | no_return

Same as list_aliases/2 but raise on error.

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list_grants(client, input)

Specs:

  • list_grants(client :: ExAws.KMS.t, input :: list_grants_request) :: ExAws.Request.JSON.response_t

ListGrants

List the grants for a specified key.

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list_grants!(client, input)

Specs:

  • list_grants!(client :: ExAws.KMS.t, input :: list_grants_request) :: ExAws.Request.JSON.success_t | no_return

Same as list_grants/2 but raise on error.

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list_key_policies(client, input)

Specs:

ListKeyPolicies

Retrieves a list of policies attached to a key.

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list_key_policies!(client, input)

Specs:

Same as list_key_policies/2 but raise on error.

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list_keys(client, input)

Specs:

  • list_keys(client :: ExAws.KMS.t, input :: list_keys_request) :: ExAws.Request.JSON.response_t

ListKeys

Lists the customer master keys.

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list_keys!(client, input)

Specs:

  • list_keys!(client :: ExAws.KMS.t, input :: list_keys_request) :: ExAws.Request.JSON.success_t | no_return

Same as list_keys/2 but raise on error.

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put_key_policy(client, input)

Specs:

PutKeyPolicy

Attaches a policy to the specified key.

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put_key_policy!(client, input)

Specs:

  • put_key_policy!(client :: ExAws.KMS.t, input :: put_key_policy_request) :: ExAws.Request.JSON.success_t | no_return

Same as put_key_policy/2 but raise on error.

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re_encrypt(client, input)

Specs:

  • re_encrypt(client :: ExAws.KMS.t, input :: re_encrypt_request) :: ExAws.Request.JSON.response_t

ReEncrypt

Encrypts data on the server side with a new customer master key without exposing the plaintext of the data on the client side. The data is first decrypted and then encrypted. This operation can also be used to change the encryption context of a ciphertext.

Unlike other actions, ReEncrypt is authorized twice - once as ReEncryptFrom on the source key and once as ReEncryptTo on the destination key. We therefore recommend that you include the "action":"kms:ReEncrypt*" statement in your key policies to permit re-encryption from or to the key. The statement is included automatically when you authorize use of the key through the console but must be included manually when you set a policy by using the PutKeyPolicy function.

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re_encrypt!(client, input)

Specs:

  • re_encrypt!(client :: ExAws.KMS.t, input :: re_encrypt_request) :: ExAws.Request.JSON.success_t | no_return

Same as re_encrypt/2 but raise on error.

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retire_grant(client, input)

Specs:

  • retire_grant(client :: ExAws.KMS.t, input :: retire_grant_request) :: ExAws.Request.JSON.response_t

RetireGrant

Retires a grant. You can retire a grant when you’re done using it to clean up. You should revoke a grant when you intend to actively deny operations that depend on it. The following are permitted to call this API:

  • The account that created the grant

  • The RetiringPrincipal, if present

  • The GranteePrincipal, if RetireGrant is a grantee operation

The grant to retire must be identified by its grant token or by a combination of the key ARN and the grant ID. A grant token is a unique variable-length base64-encoded string. A grant ID is a 64 character unique identifier of a grant. Both are returned by the CreateGrant function.

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retire_grant!(client, input)

Specs:

  • retire_grant!(client :: ExAws.KMS.t, input :: retire_grant_request) :: ExAws.Request.JSON.success_t | no_return

Same as retire_grant/2 but raise on error.

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revoke_grant(client, input)

Specs:

  • revoke_grant(client :: ExAws.KMS.t, input :: revoke_grant_request) :: ExAws.Request.JSON.response_t

RevokeGrant

Revokes a grant. You can revoke a grant to actively deny operations that depend on it.

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revoke_grant!(client, input)

Specs:

  • revoke_grant!(client :: ExAws.KMS.t, input :: revoke_grant_request) :: ExAws.Request.JSON.success_t | no_return

Same as revoke_grant/2 but raise on error.

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update_alias(client, input)

Specs:

  • update_alias(client :: ExAws.KMS.t, input :: update_alias_request) :: ExAws.Request.JSON.response_t

UpdateAlias

Updates an alias to associate it with a different key.

An alias name can contain only alphanumeric characters, forward slashes (/), underscores (_), and dashes (-). An alias must start with the word “alias” followed by a forward slash (alias/). An alias that begins with “aws” after the forward slash (alias/aws…) is reserved by Amazon Web Services (AWS).

An alias is not a property of a key. Therefore, an alias can be associated with and disassociated from an existing key without changing the properties of the key.

Note that you cannot create or update an alias that represents a key in another account.

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update_alias!(client, input)

Specs:

  • update_alias!(client :: ExAws.KMS.t, input :: update_alias_request) :: ExAws.Request.JSON.success_t | no_return

Same as update_alias/2 but raise on error.

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update_key_description(client, input)

Specs:

UpdateKeyDescription

Updates the description of a key.

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update_key_description!(client, input)

Specs:

Same as update_key_description/2 but raise on error.

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