Iso20022

KeyExchangeResponse

cain.012.001.01

The KeyExchangeResponse message is sent by an acquirer, an issuer or an agent to answer to a KeyExchangeInitiation message and complete a cryptographic key exchange.

Message Construction

Every ISO20022 message has at the highest level what we call ‘building blocks’. Because the message is constructed as immutable records, the association is by composition. Below you can see the relationship between the message and its constituent building blocks: For comparison, see the ISO20022 official specification

classDiagram
     direction LR
%% KeyExchangeResponse recursion level 0 with max 0
KeyExchangeResponse *-- "1..1" Header17 : Header
KeyExchangeResponse *-- "1..1" AcquirerKeyExchangeResponse1 : KeyExchangeResponse
KeyExchangeResponse *-- "1..1" ContentInformationType12 : SecurityTrailer

Now, we will zero-in one-by-one on each of these building blocks.

Header building block

Information related to the protocol management. Set of characteristics related to the protocol. For comparison, see the ISO20022 official specification

classDiagram
   direction tb
%% Header17 recursion level 0 with max 1
class Header17{
    MessageFunction MessageFunction6Code
    ProtocolVersion IsoMax6Text
    ExchangeIdentification IsoMax3NumericText
    ReTransmissionCounter IsoMax3NumericText
    CreationDateTime IsoISODateTime
}
Header17 *-- "1..1" GenericIdentification73 : InitiatingParty
Header17 *-- "0..1" GenericIdentification73 : RecipientParty
Header17 *-- "0..0" Traceability3 : Traceability
%% GenericIdentification73 recursion level 1 with max 1
class GenericIdentification73{
    Identification IsoMax35Text
    Type PartyType9Code
    Issuer PartyType9Code
    Country IsoMin2Max3AlphaText
    ShortName IsoMax35Text
}
%% GenericIdentification73 recursion level 1 with max 1
class GenericIdentification73{
    Identification IsoMax35Text
    Type PartyType9Code
    Issuer PartyType9Code
    Country IsoMin2Max3AlphaText
    ShortName IsoMax35Text
}
%% Traceability3 recursion level 1 with max 1
class Traceability3{
    TraceDateTimeIn IsoISODateTime
    TraceDateTimeOut IsoISODateTime
}
Traceability3 *-- "1..1" GenericIdentification74 : RelayIdentification

Header17 members

Member name Description Data Type / Multiplicity
MessageFunction Identifies the type of process related to the message. MessageFunction6Code - Required 1..1
ProtocolVersion Version of the acquirer to issuer protocol specifications. IsoMax6Text - Required 1..1
ExchangeIdentification Unique identification of an exchange occurrence. IsoMax3NumericText - Required 1..1
ReTransmissionCounter Number of retransmission of the message. Incremented by one for each retransmission. IsoMax3NumericText - Optional 0..1
CreationDateTime Date and time at which the message was sent. IsoISODateTime - Required 1..1
InitiatingParty Unique identification of the partner that has initiated the exchange. GenericIdentification73 - Required 1..1
RecipientParty Unique identification of the partner that is the recipient of the message exchange. GenericIdentification73 - Optional 0..1
Traceability Identification of partners involved in exchange from the merchant to the issuer, with the relative timestamp of their exchanges. Traceability3 - Unknown 0..0

KeyExchangeResponse building block

Information related to the response to a key exchange. Information related to the response to a key exchange. For comparison, see the ISO20022 official specification

classDiagram
   direction tb
%% AcquirerKeyExchangeResponse1 recursion level 0 with max 1
AcquirerKeyExchangeResponse1 *-- "1..1" CardTransactionEnvironment6 : Environment
AcquirerKeyExchangeResponse1 *-- "1..1" CardTransaction14 : Transaction
%% CardTransactionEnvironment6 recursion level 1 with max 1
CardTransactionEnvironment6 *-- "1..1" GenericIdentification73 : SendingInstitution
CardTransactionEnvironment6 *-- "1..1" GenericIdentification73 : ReceivingInstitution
%% CardTransaction14 recursion level 1 with max 1
class CardTransaction14{
    KeyExchangeType CardServiceType3Code
    InitiatorDateTime IsoISODateTime
}
CardTransaction14 *-- "0..0" KEKIdentifier3 : KeyVerification
CardTransaction14 *-- "0..0" CryptographicKey6 : Key
CardTransaction14 *-- "1..1" ResponseType2 : TransactionResponse

AcquirerKeyExchangeResponse1 members

Member name Description Data Type / Multiplicity
Environment Environment of the transaction. CardTransactionEnvironment6 - Required 1..1
Transaction Key exchange transaction. CardTransaction14 - Required 1..1

SecurityTrailer building block

Trailer of the message containing a MAC or a digital signature. General cryptographic message syntax (CMS) containing protected data. For comparison, see the ISO20022 official specification

classDiagram
   direction tb
%% ContentInformationType12 recursion level 0 with max 1
class ContentInformationType12{
    ContentType ContentType2Code
}
ContentInformationType12 *-- "0..1" EnvelopedData4 : EnvelopedData
ContentInformationType12 *-- "0..1" AuthenticatedData4 : AuthenticatedData
ContentInformationType12 *-- "0..1" SignedData4 : SignedData
ContentInformationType12 *-- "0..1" DigestedData4 : DigestedData
%% EnvelopedData4 recursion level 1 with max 1
class EnvelopedData4{
    Version IsoNumber
}
EnvelopedData4 *-- "1..0" IRecipient4Choice : Recipient
EnvelopedData4 *-- "0..1" EncryptedContent3 : EncryptedContent
%% AuthenticatedData4 recursion level 1 with max 1
class AuthenticatedData4{
    Version IsoNumber
    MAC IsoMax140Binary
}
AuthenticatedData4 *-- "1..0" IRecipient4Choice : Recipient
AuthenticatedData4 *-- "1..1" AlgorithmIdentification15 : MACAlgorithm
AuthenticatedData4 *-- "1..1" EncapsulatedContent3 : EncapsulatedContent
%% SignedData4 recursion level 1 with max 1
class SignedData4{
    Version IsoNumber
    Certificate IsoMax5000Binary
}
SignedData4 *-- "1..0" AlgorithmIdentification16 : DigestAlgorithm
SignedData4 *-- "1..1" EncapsulatedContent3 : EncapsulatedContent
SignedData4 *-- "1..0" Signer3 : Signer
%% DigestedData4 recursion level 1 with max 1
class DigestedData4{
    Version IsoNumber
    Digest IsoMax140Binary
}
DigestedData4 *-- "1..1" AlgorithmIdentification16 : DigestAlgorithm
DigestedData4 *-- "1..1" EncapsulatedContent3 : EncapsulatedContent

ContentInformationType12 members

Member name Description Data Type / Multiplicity
ContentType Type of data protection. ContentType2Code - Required 1..1
EnvelopedData Data protection by encryption, with a session key. EnvelopedData4 - Optional 0..1
AuthenticatedData Data protection by a message authentication code (MAC). AuthenticatedData4 - Optional 0..1
SignedData Data protected by a digital signatures. SignedData4 - Optional 0..1
DigestedData Data protected by a digest. DigestedData4 - Optional 0..1

Extensibility and generalization considerations

To facilitate generalized design patterns in the system, the KeyExchangeResponse implementation follows a specific implementaiton pattern. First of all, KeyExchangeResponse impleemnts IOuterRecord indicating it is the outermost logical part of the message definition. Like all message wrappers, KeyExchangeResponseDocument implements IOuterDocument. Because KeyExchangeResponse implements IOuterDocument, it is a suitable template parameter for IOuterDocument, and causes the internal ‘Message’ to be of type KeyExchangeResponse.

classDiagram
    class IOuterRecord
    KeyExchangeResponse --|> IOuterRecord : Implements
    KeyExchangeResponseDocument --|> IOuterDocument~KeyExchangeResponse~ : Implements
    class IOuterDocument~KeyExchangeResponse~ {
        KeyExchangeResponse Message
     }

Document wrapper for serialization

The only real purpose KeyExchangeResponseDocument serves is to cause the document to be serialized into the ‘urn:iso:std:iso:20022:tech:xsd:cain.012.001.01’ namespace. Therefore, it will probably be the usual practice to build the message and construct this wrapper at the last minute using KeyExchangeResponse.ToDocument() method. The returned KeyExchangeResponseDocument value will serialize correctly according to ISO 20022 standards.

classDiagram
    KeyExchangeResponseDocument *-- KeyExchangeResponse : Document

Sample of message format

This is an abbreviated version of what the message should look like.

<Document xmlns="urn:iso:std:iso:20022:tech:xsd:cain.012.001.01">
    <KeyXchgRspn>
        <Hdr>
            <!-- Header inner content -->
        </Hdr>
        <KeyXchgRspn>
            <!-- KeyExchangeResponse inner content -->
        </KeyXchgRspn>
        <SctyTrlr>
            <!-- SecurityTrailer inner content -->
        </SctyTrlr>
    </KeyXchgRspn>
</Document>

Data from ISO specification

This is the technical data from the specification document.

<messageDefinition
  xmi:id="_UPyNIHvQEeS2PZh7wUMQog"
  nextVersions="_mpuu1lWdEeeiG_nL4vgKnQ"
  name="KeyExchangeResponse"
  definition="The KeyExchangeResponse message is sent by an acquirer, an issuer or an agent to answer to a KeyExchangeInitiation message and complete a cryptographic key exchange."
  registrationStatus="Registered"
  messageSet="_urpIICeJEeOCeO5e7islRQ"
  xmlTag="KeyXchgRspn"
  rootElement="Document"
  xmlns:xmi="http://www.omg.org/XMI">
  <messageBuildingBlock
    xmi:id="_djiQcHvQEeS2PZh7wUMQog"
    name="Header"
    definition="Information related to the protocol management."
    registrationStatus="Provisionally Registered"
    maxOccurs="1"
    minOccurs="1"
    xmlTag="Hdr"
    complexType="_l60LgXq_EeSA34QF-FhTBw" />
  <messageBuildingBlock
    xmi:id="_MSqJEHvREeS2PZh7wUMQog"
    name="KeyExchangeResponse"
    definition="Information related to the response to a key exchange."
    registrationStatus="Provisionally Registered"
    maxOccurs="1"
    minOccurs="1"
    xmlTag="KeyXchgRspn"
    complexType="_HDOPwHvREeS2PZh7wUMQog" />
  <messageBuildingBlock
    xmi:id="_GvIZoHvSEeS2PZh7wUMQog"
    name="SecurityTrailer"
    definition="Trailer of the message containing a MAC or a digital signature."
    registrationStatus="Provisionally Registered"
    maxOccurs="1"
    minOccurs="1"
    xmlTag="SctyTrlr"
    complexType="_PwIbYWmPEeS7iYydEtv3Ug" />
  <messageDefinitionIdentifier
    businessArea="cain"
    messageFunctionality="012"
    flavour="001"
    version="01" />
</messageDefinition>

ISO Building Blocks

The following items are used as building blocks to construct this message.