Amazon Web Services – AWS Key Management Service Best Practices Page 1 Introduction AWS Key Management Service (AWS KMS) is a managed service that makes it easy for you to create and control the encryption keys used to encrypt your data. AWS KMS uses Hardware Security Modules (HSMs) to protect the security of your keys. In envelope encryption we generate a data key by using our CMK at KMS. When generating the data key, AWS sends us both the plaintext key and the encrypted key (using our CMK). Then we use the plaintext data key generated to encrypt our data. After encrypting the data we destroy the plaintext key and keep the encrypted key with us. Feb 29, 2016 AWS Key Management Service (AWS KMS): AWS Key Management Service (KMS) is an Amazon Web Services product that allows administrators to create, delete and control keys that encrypt data stored in AWS databases and products.

If you use Amazon AWS for nearly anything, then you are probably familiar with KMS, the Amazon Key Management Service.

GdkwpEncryptionContext - A set of key-value pairs that represents additional authenticated data. For more information, see Encryption Context in the AWS Key Management Service Developer Guide. GdkwpNumberOfBytes - The length of the data encryption key in bytes. For example, use the value 64 to generate a 512-bit data key (64 bytes is 512 bits). Using data keys is a great way to work with KMS, but when you do that, you must understand that you need to rely on your host system's ability to encrypt and decrypt the data with the keys provided. KMS Data Keys provide envelope encryption support and the encryption and decryption that KMS provides is for the key itself, not your data. For more information about building AWS IAM policy documents with Terraform, see the AWS IAM Policy Document Guide. Deletionwindowindays - (Optional) Duration in days after which the key is deleted after destruction of the resource, must be between 7 and 30 days. Jul 23, 2018  This article was first published on my blog as 'Painlessly storing security sensitive data using AWS KMS and OpenSSL'. TL;DR: In this post, I am going to introduce a method using AWS KMS, envelope encryption and OpenSSL as an alternative for securing private data in your public GitHub/ Bitbucket repositories. You will learn how to use AWS KMS and how to implement your own encryption.

KMS is a service which allows API-level access to cryptographic primitives without the expense and complexity of a full-fledged HSM or CloudHSM implementation. There are trade-offs in that the key material does reside on servers rather than tamper-proof devices, but these risks should be acceptable to a wide range of customers based on the care Amazon has put into the product. You should perform your own diligence on whether KMS is appropriate for your environment. If the security profile is not adequate, you should consider a stronger product such as CloudHSM or managing your own HSM solutions.

Aws Kms Generate-data-key

The goal here is to provide some introductory code on how to perform envelope encrypt a message using the AWS KMS API.

KMS allows you to encrypt messages of up to 4kb in size directly using the encrypt()/decrypt() API.To exceed these limitations, you must use a technique called 'envelope encryption'.

Aws Kms Key Rotation

Read more about that here:http://docs.aws.amazon.com/kms/latest/developerguide/workflow.html

The steps are:

1. Generate a new Customer Master Key using the Boto API or the AWS Console. Note that CMKs are region-specific, so you will need to generate keys per region in a multi-region configuration.
2. Generate a Data Encryption Key via the generate_data_key() API. This API will return the Plaintext key, so take care with this field and clear it from memory when no longer needed. The CiphertextBlob is the Plaintext-key encrypted under the CMK. You will need to preserve this data for decryption purposes.
3. Locally encrypt your data. In this example, we use PyCrypto's implementation of AES using their defaults (CFB mode, no IV), so be sure you understand this thoroughly before using any example code in your production environment.
4. Store your locally encrypted data with the CiphertextBlob.
5. When decryption is needed, pass the CiphertextBlob to the KMS decrypt() API which will return the Plaintext encryption key.
6. Use PyCrypto's AES routines to create a new context and decrypt the encrypted ciphertext.

[ aws . kms ]

Description¶

Generates a unique symmetric data key. This operation returns a plaintext copy of the data key and a copy that is encrypted under a customer master key (CMK) that you specify. You can use the plaintext key to encrypt your data outside of AWS KMS and store the encrypted data key with the encrypted data.

To generate a data key, specify the symmetric CMK that will be used to encrypt the data key. You cannot use an asymmetric CMK to generate data keys. To get the type of your CMK, use the DescribeKey operation.

You must also specify the length of the data key. Firefox download for mac 10.10.3. Use either the KeySpec or NumberOfBytes parameters (but not both). For 128-bit and 256-bit data keys, use the KeySpec parameter.

If the operation succeeds, the plaintext copy of the data key is in the Plaintext field of the response, and the encrypted copy of the data key in the CiphertextBlob field.

To get only an encrypted copy of the data key, use GenerateDataKeyWithoutPlaintext . To generate an asymmetric data key pair, use the GenerateDataKeyPair or GenerateDataKeyPairWithoutPlaintext operation. To get a cryptographically secure random byte string, use GenerateRandom .

You can use the optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext , you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the AWS Key Management Service Developer Guide .

The CMK that you use for this operation must be in a compatible key state. For details, see How Key State Affects Use of a Customer Master Key in the AWS Key Management Service Developer Guide .

We recommend that you use the following pattern to encrypt data locally in your application:

• Use the GenerateDataKey operation to get a data encryption key.
• Use the plaintext data key (returned in the Plaintext field of the response) to encrypt data locally, then erase the plaintext data key from memory.
• Store the encrypted data key (returned in the CiphertextBlob field of the response) alongside the locally encrypted data.

To decrypt data locally:

• Use the Decrypt operation to decrypt the encrypted data key. The operation returns a plaintext copy of the data key.
• Use the plaintext data key to decrypt data locally, then erase the plaintext data key from memory.

See also: AWS API Documentation

See 'aws help' for descriptions of global parameters.

Synopsis¶

Options¶

--key-id (string)

Identifies the symmetric CMK that encrypts the data key.

To specify a CMK, use its key ID, Amazon Resource Name (ARN), alias name, or alias ARN. When using an alias name, prefix it with 'alias/' . To specify a CMK in a different AWS 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 CMK, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

--encryption-context (map)

Specifies the encryption context that will be used when encrypting the data key.

An encryption context is a collection of non-secret key-value pairs that represents additional authenticated data. When you use an encryption context to encrypt data, you must specify the same (an exact case-sensitive match) encryption context to decrypt the data. An encryption context is optional when encrypting with a symmetric CMK, but it is highly recommended.

For more information, see Encryption Context in the AWS Key Management Service Developer Guide .

Shorthand Syntax:

JSON Syntax:

--number-of-bytes (integer)

Specifies the length of the data key in bytes. For example, use the value 64 to generate a 512-bit data key (64 bytes is 512 bits). For 128-bit (16-byte) and 256-bit (32-byte) data keys, use the KeySpec parameter.

You must specify either the KeySpec or the NumberOfBytes parameter (but not both) in every GenerateDataKey request.

--key-spec (string) Bamboo public key generated for this repository.

Aws Kms Generate Data Key Example For Students

Specifies the length of the data key. Use AES_128 to generate a 128-bit symmetric key, or AES_256 to generate a 256-bit symmetric key.

You must specify either the KeySpec or the NumberOfBytes parameter (but not both) in every GenerateDataKey request.

Possible values:

• AES_256
• AES_128

--grant-tokens (list)

A list of grant tokens.

For more information, see Grant Tokens in the AWS Key Management Service Developer Guide .

Syntax:

--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.

See 'aws help' for descriptions of global parameters.

Output¶

CiphertextBlob -> (blob)

Plaintext -> (blob)

Aws Kms Generate Data Key Examples

KeyId -> (string)

Aws Kms Key Policy