ExportKey

Exports a key from AWS Payment Cryptography.

AWS Payment Cryptography simplifies key exchange by replacing the existing paper-based approach with a modern electronic approach. With ExportKey you can export symmetric keys using either symmetric and asymmetric key exchange mechanisms. Using this operation, you can share your AWS Payment Cryptography generated keys with other service partners to perform cryptographic operations outside of AWS Payment Cryptography

For symmetric key exchange, AWS Payment Cryptography uses the ANSI X9 TR-31 norm in accordance with PCI PIN guidelines. And for asymmetric key exchange, AWS Payment Cryptography supports ANSI X9 TR-34 norm and RSA wrap and unwrap key exchange mechanism. Asymmetric key exchange methods are typically used to establish bi-directional trust between the two parties exhanging keys and are used for initial key exchange such as Key Encryption Key (KEK). After which you can export working keys using symmetric method to perform various cryptographic operations within AWS Payment Cryptography.

The TR-34 norm is intended for exchanging 3DES keys only and keys are imported in a WrappedKeyBlock format. Key attributes (such as KeyUsage, KeyAlgorithm, KeyModesOfUse, Exportability) are contained within the key block. With RSA wrap and unwrap, you can exchange both 3DES and AES-128 keys. The keys are imported in a WrappedKeyCryptogram format and you will need to specify the key attributes during import.

You can also use ExportKey functionality to generate and export an IPEK (Initial Pin Encryption Key) from AWS Payment Cryptography using either TR-31 or TR-34 export key exchange. IPEK is generated from BDK (Base Derivation Key) and ExportDukptInitialKey attribute KSN (KeySerialNumber). The generated IPEK does not persist within AWS Payment Cryptography and has to be re-generated each time during export.

For key exchange using TR-31 or TR-34 key blocks, you can also export optional blocks within the key block header which contain additional attribute information about the key. The KeyVersion within KeyBlockHeaders indicates the version of the key within the key block. Furthermore, KeyExportability within KeyBlockHeaders can be used to further restrict exportability of the key after export from AWS Payment Cryptography.

The OptionalBlocks contain the additional data related to the key. For information on data type that can be included within optional blocks, refer to ASC X9.143-2022.

To export initial keys (KEK) or IPEK using TR-34

Using this operation, you can export initial key using TR-34 asymmetric key exchange. You can only export KEK generated within AWS Payment Cryptography. In TR-34 terminology, the sending party of the key is called Key Distribution Host (KDH) and the receiving party of the key is called Key Receiving Device (KRD). During key export process, KDH is AWS Payment Cryptography which initiates key export and KRD is the user receiving the key.

To initiate TR-34 key export, the KRD must obtain an export token by calling GetParametersForExport. This operation also generates a key pair for the purpose of key export, signs the key and returns back the signing public key certificate (also known as KDH signing certificate) and root certificate chain. The KDH uses the private key to sign the the export payload and the signing public key certificate is provided to KRD to verify the signature. The KRD can import the root certificate into its Hardware Security Module (HSM), as required. The export token and the associated KDH signing certificate expires after 7 days.

Next the KRD generates a key pair for the the purpose of encrypting the KDH key and provides the public key cerificate (also known as KRD wrapping certificate) back to KDH. The KRD will also import the root cerificate chain into AWS Payment Cryptography by calling ImportKey for RootCertificatePublicKey. The KDH, AWS Payment Cryptography, will use the KRD wrapping cerificate to encrypt (wrap) the key under export and signs it with signing private key to generate a TR-34 WrappedKeyBlock. For more information on TR-34 key export, see section Exporting symmetric keys in the AWS Payment Cryptography User Guide.

Set the following parameters:

When this operation is successful, AWS Payment Cryptography returns the KEK or IPEK as a TR-34 WrappedKeyBlock.

To export initial keys (KEK) or IPEK using RSA Wrap and Unwrap

Using this operation, you can export initial key using asymmetric RSA wrap and unwrap key exchange method. To initiate export, generate an asymmetric key pair on the receiving HSM and obtain the public key certificate in PEM format (base64 encoded) for the purpose of wrapping and the root certifiate chain. Import the root certificate into AWS Payment Cryptography by calling ImportKey for RootCertificatePublicKey.

Next call ExportKey and set the following parameters:

When this operation is successful, AWS Payment Cryptography returns the WrappedKeyCryptogram.

To export working keys or IPEK using TR-31

Using this operation, you can export working keys or IPEK using TR-31 symmetric key exchange. In TR-31, you must use an initial key such as KEK to encrypt or wrap the key under export. To establish a KEK, you can use CreateKey or ImportKey.

Set the following parameters:

When this operation is successful, AWS Payment Cryptography returns the working key or IPEK as a TR-31 WrappedKeyBlock.

Cross-account use: This operation can't be used across different AWS accounts.

Related operations:

Request Syntax

{
   "ExportAttributes": { 
      "ExportDukptInitialKey": { 
         "KeySerialNumber": "string"
      },
      "KeyCheckValueAlgorithm": "string"
   },
   "ExportKeyIdentifier": "string",
   "KeyMaterial": { ... }
}

Request Parameters

The request accepts the following data in JSON format.

Response Syntax

{
   "WrappedKey": { 
      "KeyCheckValue": "string",
      "KeyCheckValueAlgorithm": "string",
      "KeyMaterial": "string",
      "WrappedKeyMaterialFormat": "string",
      "WrappingKeyArn": "string"
   }
}

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

Errors

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: