PaymentCryptographyDataPlane / Client / decrypt_data

decrypt_data#

PaymentCryptographyDataPlane.Client.decrypt_data(**kwargs)#

Decrypts ciphertext data to plaintext using a symmetric (TDES, AES), asymmetric (RSA), or derived (DUKPT or EMV) encryption key scheme. For more information, see Decrypt data in the Amazon Web Services Payment Cryptography User Guide.

You can use an decryption key generated within Amazon Web Services Payment Cryptography, or you can import your own decryption key by calling ImportKey. For this operation, the key must have KeyModesOfUse set to Decrypt. In asymmetric decryption, Amazon Web Services Payment Cryptography decrypts the ciphertext using the private component of the asymmetric encryption key pair. For data encryption outside of Amazon Web Services Payment Cryptography, you can export the public component of the asymmetric key pair by calling GetPublicCertificate.

This operation also supports dynamic keys, allowing you to pass a dynamic decryption key as a TR-31 WrappedKeyBlock. This can be used when key material is frequently rotated, such as during every card transaction, and there is need to avoid importing short-lived keys into Amazon Web Services Payment Cryptography. To decrypt using dynamic keys, the keyARN is the Key Encryption Key (KEK) of the TR-31 wrapped decryption key material. The incoming wrapped key shall have a key purpose of D0 with a mode of use of B or D. For more information, see Using Dynamic Keys in the Amazon Web Services Payment Cryptography User Guide.

For symmetric and DUKPT decryption, Amazon Web Services Payment Cryptography supports TDES and AES algorithms. For EMV decryption, Amazon Web Services Payment Cryptography supports TDES algorithms. For asymmetric decryption, Amazon Web Services Payment Cryptography supports RSA.

When you use TDES or TDES DUKPT, the ciphertext data length must be a multiple of 8 bytes. For AES or AES DUKPT, the ciphertext data length must be a multiple of 16 bytes. For RSA, it sould be equal to the key size unless padding is enabled.

For information about valid keys for this operation, see Understanding key attributes and Key types for specific data operations in the Amazon Web Services Payment Cryptography User Guide.

Cross-account use: This operation can’t be used across different Amazon Web Services accounts.

Related operations:

Request Syntax

response = client.decrypt_data(
    KeyIdentifier='string',
    CipherText='string',
    DecryptionAttributes={
        'Symmetric': {
            'Mode': 'ECB'|'CBC'|'CFB'|'CFB1'|'CFB8'|'CFB64'|'CFB128'|'OFB',
            'InitializationVector': 'string',
            'PaddingType': 'PKCS1'|'OAEP_SHA1'|'OAEP_SHA256'|'OAEP_SHA512'
        },
        'Asymmetric': {
            'PaddingType': 'PKCS1'|'OAEP_SHA1'|'OAEP_SHA256'|'OAEP_SHA512'
        },
        'Dukpt': {
            'KeySerialNumber': 'string',
            'Mode': 'ECB'|'CBC',
            'DukptKeyDerivationType': 'TDES_2KEY'|'TDES_3KEY'|'AES_128'|'AES_192'|'AES_256',
            'DukptKeyVariant': 'BIDIRECTIONAL'|'REQUEST'|'RESPONSE',
            'InitializationVector': 'string'
        },
        'Emv': {
            'MajorKeyDerivationMode': 'EMV_OPTION_A'|'EMV_OPTION_B',
            'PrimaryAccountNumber': 'string',
            'PanSequenceNumber': 'string',
            'SessionDerivationData': 'string',
            'Mode': 'ECB'|'CBC',
            'InitializationVector': 'string'
        }
    },
    WrappedKey={
        'WrappedKeyMaterial': {
            'Tr31KeyBlock': 'string',
            'DiffieHellmanSymmetricKey': {
                'CertificateAuthorityPublicKeyIdentifier': 'string',
                'PublicKeyCertificate': 'string',
                'KeyAlgorithm': 'TDES_2KEY'|'TDES_3KEY'|'AES_128'|'AES_192'|'AES_256',
                'KeyDerivationFunction': 'NIST_SP800'|'ANSI_X963',
                'KeyDerivationHashAlgorithm': 'SHA_256'|'SHA_384'|'SHA_512',
                'SharedInformation': 'string'
            }
        },
        'KeyCheckValueAlgorithm': 'CMAC'|'ANSI_X9_24'
    }
)

Parameters:

KeyIdentifier (string) –
[REQUIRED]

The keyARN of the encryption key that Amazon Web Services Payment Cryptography uses for ciphertext decryption.

When a WrappedKeyBlock is provided, this value will be the identifier to the key wrapping key. Otherwise, it is the key identifier used to perform the operation.
CipherText (string) –
[REQUIRED]

The ciphertext to decrypt.
DecryptionAttributes (dict) –
[REQUIRED]

The encryption key type and attributes for ciphertext decryption.

Note
This is a Tagged Union structure. Only one of the following top level keys can be set: Symmetric, Asymmetric, Dukpt, Emv.
- Symmetric (dict) –
  
  Parameters that are required to perform encryption and decryption using symmetric keys.
  - Mode (string) – [REQUIRED]
    
    The block cipher method to use for encryption.
  - InitializationVector (string) –
    
    An input used to provide the intial state. If no value is provided, Amazon Web Services Payment Cryptography defaults it to zero.
  - PaddingType (string) –
    
    The padding to be included with the data.
- Asymmetric (dict) –
  
  Parameters for plaintext encryption using asymmetric keys.
  - PaddingType (string) –
    
    The padding to be included with the data.
- Dukpt (dict) –
  
  Parameters that are required to encrypt plaintext data using DUKPT.
  - KeySerialNumber (string) – [REQUIRED]
    
    The unique identifier known as Key Serial Number (KSN) that comes from an encrypting device using DUKPT encryption method. The KSN is derived from the encrypting device unique identifier and an internal transaction counter.
  - Mode (string) –
    
    The block cipher method to use for encryption.
    
    The default is CBC.
  - DukptKeyDerivationType (string) –
    
    The key type encrypted using DUKPT from a Base Derivation Key (BDK) and Key Serial Number (KSN). This must be less than or equal to the strength of the BDK. For example, you can’t use AES_128 as a derivation type for a BDK of AES_128 or TDES_2KEY
  - DukptKeyVariant (string) –
    
    The type of use of DUKPT, which can be incoming data decryption, outgoing data encryption, or both.
  - InitializationVector (string) –
    
    An input used to provide the intial state. If no value is provided, Amazon Web Services Payment Cryptography defaults it to zero.
- Emv (dict) –
  
  Parameters for plaintext encryption using EMV keys.
  - MajorKeyDerivationMode (string) – [REQUIRED]
    
    The EMV derivation mode to use for ICC master key derivation as per EMV version 4.3 book 2.
  - PrimaryAccountNumber (string) – [REQUIRED]
    
    The Primary Account Number (PAN), a unique identifier for a payment credit or debit card and associates the card to a specific account holder.
  - PanSequenceNumber (string) – [REQUIRED]
    
    A number that identifies and differentiates payment cards with the same Primary Account Number (PAN). Typically 00 is used, if no value is provided by the terminal.
  - SessionDerivationData (string) – [REQUIRED]
    
    The derivation value used to derive the ICC session key. It is typically the application transaction counter value padded with zeros or previous ARQC value padded with zeros as per EMV version 4.3 book 2.
  - Mode (string) –
    
    The block cipher method to use for encryption.
  - InitializationVector (string) –
    
    An input used to provide the intial state. If no value is provided, Amazon Web Services Payment Cryptography defaults it to zero.
WrappedKey (dict) –
The WrappedKeyBlock containing the encryption key for ciphertext decryption.
- WrappedKeyMaterial (dict) – [REQUIRED]
  
  Parameter information of a WrappedKeyBlock for encryption key exchange.
  
  Note
  This is a Tagged Union structure. Only one of the following top level keys can be set: Tr31KeyBlock, DiffieHellmanSymmetricKey.
  - Tr31KeyBlock (string) –
    
    The TR-31 wrapped key block.
  - DiffieHellmanSymmetricKey (dict) –
    
    The parameter information for deriving a ECDH shared key.
    - CertificateAuthorityPublicKeyIdentifier (string) – [REQUIRED]
      
      The keyArn of the certificate that signed the client’s PublicKeyCertificate.
    - PublicKeyCertificate (string) – [REQUIRED]
      
      The client’s public key certificate in PEM format (base64 encoded) to use for ECDH key derivation.
    - KeyAlgorithm (string) – [REQUIRED]
      
      The key algorithm of the derived ECDH key.
    - KeyDerivationFunction (string) – [REQUIRED]
      
      The key derivation function to use for deriving a key using ECDH.
    - KeyDerivationHashAlgorithm (string) – [REQUIRED]
      
      The hash type to use for deriving a key using ECDH.
    - SharedInformation (string) – [REQUIRED]
      
      A byte string containing information that binds the ECDH derived key to the two parties involved or to the context of the key.
      
      It may include details like identities of the two parties deriving the key, context of the operation, session IDs, and optionally a nonce. It must not contain zero bytes, and re-using shared information for multiple ECDH key derivations is not recommended.
- KeyCheckValueAlgorithm (string) –
  
  The algorithm that Amazon Web Services Payment Cryptography uses to calculate the key check value (KCV). It is used to validate the key integrity.
  
  For TDES keys, the KCV is computed by encrypting 8 bytes, each with value of zero, with the key to be checked and retaining the 3 highest order bytes of the encrypted result. For AES keys, the KCV is computed using a CMAC algorithm where the input data is 16 bytes of zero and retaining the 3 highest order bytes of the encrypted result.

Return type:

dict

Returns:

Response Syntax

{
    'KeyArn': 'string',
    'KeyCheckValue': 'string',
    'PlainText': 'string'
}

Response Structure

(dict) –
- KeyArn (string) –
  
  The keyARN of the encryption key that Amazon Web Services Payment Cryptography uses for ciphertext decryption.
- KeyCheckValue (string) –
  
  The key check value (KCV) of the encryption key. The KCV is used to check if all parties holding a given key have the same key or to detect that a key has changed.
  
  Amazon Web Services Payment Cryptography computes the KCV according to the CMAC specification.
- PlainText (string) –
  
  The decrypted plaintext data in hexBinary format.

Exceptions

PaymentCryptographyDataPlane.Client.exceptions.ValidationException
PaymentCryptographyDataPlane.Client.exceptions.AccessDeniedException
PaymentCryptographyDataPlane.Client.exceptions.ResourceNotFoundException
PaymentCryptographyDataPlane.Client.exceptions.ThrottlingException
PaymentCryptographyDataPlane.Client.exceptions.InternalServerException