Internet DRAFT - draft-ietf-satp-core
draft-ietf-satp-core
Internet Engineering Task Force M. Hargreaves
Internet-Draft Quant Network
Intended status: Informational T. Hardjono
Expires: 10 January 2024 MIT
R. Belchior
Technico Lisboa
9 July 2023
Secure Asset Transfer Protocol (SATP)
draft-ietf-satp-core-02
Abstract
This memo This memo describes the Secure Asset Transfer (SAT)
Protocol for digital assets. SAT is a protocol operating between two
gateways that conducts the transfer of a digital asset from one
gateway to another. The protocol establishes a secure channel
between the endpoints and implements a 2-phase commit to ensure the
properties of transfer atomicity, consistency, isolation and
durability.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on 10 January 2024.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions used in this document . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. The Secure Asset Transfer Protocol . . . . . . . . . . . . . 5
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. SAT Model . . . . . . . . . . . . . . . . . . . . . . . . 6
4.3. Types of APIs . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Types of Flows . . . . . . . . . . . . . . . . . . . . . 7
4.5. Resources and Identifiers . . . . . . . . . . . . . . . . 7
5. SATP Message Format, identifiers and Descriptors . . . . . . 7
5.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. SATP Message Format . . . . . . . . . . . . . . . . . . . 8
5.3. Digital Asset Resource Descriptors . . . . . . . . . . . 9
5.3.1. Organization Identifier . . . . . . . . . . . . . . . 9
5.3.2. Gateway / Endpoint ID . . . . . . . . . . . . . . . . 9
5.3.3. Network or system Identifier . . . . . . . . . . . . 9
5.3.4. Resource . . . . . . . . . . . . . . . . . . . . . . 10
5.3.5. Examples . . . . . . . . . . . . . . . . . . . . . . 10
5.4. Digital Asset Resource Client Descriptors . . . . . . . . 10
5.4.1. Organization Identifier . . . . . . . . . . . . . . . 10
5.4.2. Gateway / Endpoint ID . . . . . . . . . . . . . . . . 10
5.4.3. Organizational Unit . . . . . . . . . . . . . . . . . 11
5.4.4. Name . . . . . . . . . . . . . . . . . . . . . . . . 11
5.4.5. Examples . . . . . . . . . . . . . . . . . . . . . . 11
5.5. Gateway Level Access Control . . . . . . . . . . . . . . 11
5.6. Negotiation of Security Protocols and Parameters . . . . 12
5.6.1. TLS Established . . . . . . . . . . . . . . . . . . . 12
5.6.2. Client offers supported credential schemes . . . . . 12
5.6.3. Server selects supported credential scheme . . . . . 12
5.6.4. Client asserts or proves identity . . . . . . . . . . 12
5.6.5. Sequence numbers initialized . . . . . . . . . . . . 12
5.6.6. Messages can now be exchanged . . . . . . . . . . . . 13
5.7. Asset Profile Identification . . . . . . . . . . . . . . 13
5.8. Application Profile Negotiation . . . . . . . . . . . . . 13
5.9. Discovery of Digital Asset Resources . . . . . . . . . . 14
6. Identity and Asset Verification Flow (Stage 0) . . . . . . . 14
7. Transfer Initiation and Commencement Flows (Stage 1) . . . . 15
7.1. Transfer Initialization Claims . . . . . . . . . . . . . 15
7.2. Conveyance of Network Capabilities and Parameters . . . . 16
7.3. Transfer Proposal Message . . . . . . . . . . . . . . . . 17
7.4. Transfer Proposal Receipt Message . . . . . . . . . . . . 18
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7.5. Transfer Proposal Reject and Conditional Reject
Message . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.6. Transfer Commence Message . . . . . . . . . . . . . . . . 20
7.7. Commence Response Message (ACK-Commence) . . . . . . . . 21
8. Lock Assertion and Receipt (Stage 2) . . . . . . . . . . . . 22
8.1. Lock Assertion Message . . . . . . . . . . . . . . . . . 23
8.2. Lock Assertion Receipt Message . . . . . . . . . . . . . 24
9. Commitment Preparation and Finalization (Stage 3) . . . . . . 24
9.1. Commit Preparation Message (Commit-Prepare) . . . . . . . 25
9.2. Commit Ready Message (Commit-Ready) . . . . . . . . . . . 26
9.3. Commit Final Assertion Message (Commit-Final) . . . . . . 27
9.4. Commit-Final Acknowledgement Receipt Message
(ACK-Final-Receipt) . . . . . . . . . . . . . . . . . . . 28
9.5. Transfer Complete Message . . . . . . . . . . . . . . . . 29
10. SATP Session Resumption . . . . . . . . . . . . . . . . . . . 29
10.1. Primary-Backup Session Resumption . . . . . . . . . . . 30
10.2. Recovery Messages . . . . . . . . . . . . . . . . . . . 31
11. Error Messages . . . . . . . . . . . . . . . . . . . . . . . 32
11.1. Closure Alerts . . . . . . . . . . . . . . . . . . . . . 32
11.2. Error Alerts . . . . . . . . . . . . . . . . . . . . . . 33
12. Security Consideration . . . . . . . . . . . . . . . . . . . 33
13. IANA Consideration . . . . . . . . . . . . . . . . . . . . . 33
14. Appendix A: Error Types . . . . . . . . . . . . . . . . . . . 34
14.1. Transfer Commence and Response errors . . . . . . . . . 34
14.2. Lock Assertion errors . . . . . . . . . . . . . . . . . 34
14.3. Lock Assertion Receipt errors . . . . . . . . . . . . . 34
14.4. Commit Preparation errors . . . . . . . . . . . . . . . 35
14.5. Commit Preparation Acknowledgement errors . . . . . . . 35
14.6. Commit Ready errors . . . . . . . . . . . . . . . . . . 35
14.7. Commit Final Assertion errors . . . . . . . . . . . . . 35
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 36
15.1. Normative References . . . . . . . . . . . . . . . . . . 36
15.2. Informative References . . . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction
This memo proposes a secure asset transfer protocol (SATP) that is
intended to be deployed between two gateway endpoints to transfer a
digital asset from an origin network to a destination network.
Both the origin and destination networks are assumed to be opaque in
the sense that the interior constructs of a given network is not
read/write accessible to unauthorized entities.
The protocol utilizes the asset burn-and-mint paradigm whereby the
asset to be transferred is permanently disabled or destroyed (burned)
at the origin network and is re-generated (minted) at the destination
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network. This is achieved through the coordinated actions of the
peer gateways handling the unidirectional transfer at the respective
networks.
A gateway is assumed to be trusted to perform the tasks involved in
the asset transfer.
The overall aim of the protocol is to ensure that the state of assets
in the origin and destination networks remain consistent, and that
asset movements into (out of) networks via gateways can be accounted
for.
There are several desirable technical properties of the protocol.
The protocol must ensure that the properties of atomicity,
consistency, isolation, and durability (ACID) are satisfied.
The requirement of consistency implies that the asset transfer
protocol always leaves both networks in a consistent state (that the
asset is located in one system/network only at any time).
Atomicity means that the protocol must guarantee that either the
transfer commits (completes) or entirely fails, where failure is
taken to mean there is no change to the state of the asset in the
origin (sender) network.
The property of isolation means that while a transfer is occurring to
a digital asset from an origin network, no other state changes can
occur to the asset.
The property of durability means that once the transfer has been
committed by both gateways, that this commitment must hold regardless
of subsequent unavailability (e.g. crash) of the gateways
implementing the SAT protocol.
All messages exchanged between gateways are assumed to run over
TLS1.2, and the endpoints at the respective gateways are associated
with a certificate indicating the legal owner (or operator) of the
gateway.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
In this document, these words will appear with that interpretation
only when in ALL CAPS. Lower case uses of these words are not to be
interpreted as carrying significance described in RFC 2119.
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3. Terminology
The following are some terminology used in the current document:
Client application: This is the application employed by a user to
interact with a gateway.
Gateway: The computer system functionally capable of acting as a
gateway in an asset transfer.
Sender gateway: The gateway that initiates a unidirectional asset
transfer.
Recipient gateway: The gateway that is the recipient side of a
unidirectional asset transfer.
Claim: An assertion made by an Entity [JWT].
Claim Type: Syntax used for representing a Claim Value [JWT].
Gateway Claim: An assertion made by a Gateway regarding the status or
condition of resources (e.g. assets, public keys, etc.) accessible to
that gateway (e.g. within its network or system).
4. The Secure Asset Transfer Protocol
4.1. Overview
The Secure Asset Transfer Protocol (SATP) is a gateway-to-gateway
protocol used by a sender gateway with a recipient gateway to perform
a unidirectional transfer of a digital asset.
The protocol defines a number of API endpoints, resources and
identifier definitions, and message flows corresponding to the asset
transfer between the two gateways.
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+----------+ +----------+
| Client | | Off-net |
| (App) | | Resource |
+----------+ +----------+
| |API Type-3|
| +----------+
| ^
V |
+----------+ |
|API Type-1| |
+------+ +----------+----+ +----+----------+ +------+
| | | | | | | | | |
| Net. | | Gateway |API | |API | Gateway | | Net. |
| NW1 |---| G1 |Type|<------>|Type| G2 |---| NW2 |
| | | | 2 | | 2 | | | |
+------+ +----------+----+ +----+----------+ +------+
Figure 1
4.2. SAT Model
The model for SATP is shown in Figure 1.
The Client (application) interacts with its local gateway (G1) over
an interface (API Type-1) in order to provide instructions to the
gateway with regards to actions to assets and related resources
located in the local system or network (NW1).
Gateways interact with each other over a gateway interface (API Type-
2). A given gateway may be required to access resources that are not
located in network NW1 or network NW2. Access to these types of
resources are performed over an off-network interface (API Type-3).
4.3. Types of APIs
The following are the types of APIs in SATP:
* Gateway APIs for client (API Type-1): This the REST APIs that
permit a Client (application) to interact with a local gateway,
and issue instructions for actions pertaining to resources
accessible to the gateway.
* Gateway APIs for peer gateways (API Type-2): This is the REST APIs
employed by two (2) peer gateways in performing unidirectional
asset transfers.
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* APIs for validation of off-network resources (API Type-3): This is
the REST APIs made available by a resource server (resource owner)
at which a gateway can access resources.
The use of these APIs is dependent on the mode of access and the type
of flow in question.
4.4. Types of Flows
The SAT protocol defines the following three (3) flows:
* Transfer Initiation flow: This flow deals with commencing a
transfer from one gateway to another. Several tasks are involved,
including (but not limited to): (i) gateway identification and
mutual authentication; (ii) exchange of asset type (definition)
information; (iii) verification of the asset definition, and
others.
* Lock-Assertion flow: This flow deals with the conveyance of signed
assertions from the sender gateway to the receiver gateway
regarding the locked status of an asset at the origin network.
* Commitment Establishment flow: This flow deals with the asset
transfer and commitment establishment between two gateways.
These flow will be discussed below.
4.5. Resources and Identifiers
(a) Resource addressing for systems or networks, using the URL
syntax.
(b) Client identification based on the URN format. These are for
identifying clients (developers and applications) who access these
resources, and which in some use-cases require access authorization.
(c) Protocol message family for negotiating authentication,
authorisation, and parameters for confidential channel establishment.
(d) Resource discovery mechanism for developers and applications to
discover resources hosted at a gateway. The gateway response is
subject to the level of access granted to that developer or
application.
5. SATP Message Format, identifiers and Descriptors
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5.1. Overview
This section describes (i) the phases of SATP; (ii) the format of
SATP messages; (iii) the format for resource descriptors; (iv) a
method for gateways to implement access controls; (iv) protocol for
negotiating security capabilities; (v) discovery and accessing
resources and provisions for backward compatibility with existing
systems.
5.2. SATP Message Format
SATP messages are exchanged between applications (clients) and
gateways (servers). They consist of protocol negotiation and
functional messages.
Messages are in JSON format, with protocol specific mandatory fields,
support for several authentication and authorization schemes and
support for a free format field for plaintext or encrypted payloads
directed at the gateway.
JSON format message, mandatory fields are shown below:
* Version: SATP protocol Version (major, minor).
* Message Type: This refers to the type of request or response to be
conveyed in this message.
* Session ID: unique identifier (UUIDv2) representing a session
between two gateways handling a single unidirectional transfer.
* Transfer-Context ID: unique optional identifier (UUIDv2)
representing the application layer context.
* Sequence Number: Monotonically increasing counter that uniquely
represents a message from a session.
* Resource URL: Location of Resource to be accessed.
* Developer URN: Assertion of developer / application identity.
* Action/Response: GET/POST and arguments (or Response Code)
* Credential Profile: Specify type of auth (e.g. SAML, OAuth,
X.509)
* Credential Block: Credential token, certificate, string
* Payload Profile: Asset profile and capabilities
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* Application Profile: Vendor or Application specific profile
* Payload: Payload for POST, responses, and local networks. The
payload is specific to the current SAT phase.
* Payload Hash: hash of the current message payload.
* Message signature: Gateway EDCSA signature over the message
Other relevant attributes may exists that need to be captured for
logging purposes.
5.3. Digital Asset Resource Descriptors
Resources are identified by URL [RFC 1738] as described below:
* The type is new: application/satres
* The access protocol is SATP.
Data included in the URL includes the folowing:
5.3.1. Organization Identifier
This MAY be a Legal Entity Identifier (LEI) or other identifier
linking resource ownership to a real world entity. Any scheme for
identifying gateway owners may be implemented (e.g. LEI directory,
closed user group membership, SWIFT BIC, etc.).
The developer or application MAY validate the identity with the
issuing authority. The identifier is not a trusted identity, but MAY
be relied on where trust has been established between the two parties
(e.g. in a closed user group).
The mechanisms to determine organizations identifiers is out of scope
for the current specification.
5.3.2. Gateway / Endpoint ID
FQDN of the SATP compliant gateway. Required to establish IP
connectivity. This MUST resolve to a valid IP address.
5.3.3. Network or system Identifier
Specific to the gateway behind which the target network operates.
This field is local to the gateway and is used to direct SATP
interactions to the correct underlying network. This value maybe
alphanumeric or a hexadecimal value.
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For example: "tradelens-network", "EU-supply-chain".
5.3.4. Resource
Specifies a resource held on the underlying network. This field must
be meaningful to the network in question but is otherwise an
arbitrary string. The underlying object it points to may be a
network address, data block, transaction ID, alias, etc. or a future
object type not yet defined.
5.3.5. Examples
satpres://quant/api.gateway1.com/swift
5.4. Digital Asset Resource Client Descriptors
Resources are identified by URN as described below:
* The type is new: application/satpclient
The URN format does not imply availability of access protocol.
Data included in the URN includes the following:
5.4.1. Organization Identifier
Legal Entity Identifier (LEI) or other identifier linking resource
ownership to a real-world entity. Any scheme for identifying Gateway
owners may be implemented (e.g. LEI directory, closed user group
membership, BIC, etc.).
The Gateway MAY validate the identity with the issuing authority.
The identifier is not a trusted identity, but MAY be relied on where
trust has been established between the two parties (e.g. in a closed
user group).
5.4.2. Gateway / Endpoint ID
Applications which interact with multiple networks can operate in a
mode whereby the application connects to its local gateway, which
then forwards application traffic to local networks and to remote
networks via other SATP gateways.
Where this is the case, this field identifies the "home" gateway for
this application. This may be required to carry out gateway to
gateway handshaking and protocol negotiation, or for the server to
look up use case specific data relating to the client.
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5.4.3. Organizational Unit
The organization unit within the organization that the client
(application or developer) belongs to. This assertion should be
backed up with authentication via the negotiated protocol.
The purpose of this field is to allow gateways to maintain access
control mapping between applications and resources that are
independent of the authentication and authorization schemes used,
supporting future changes and supporting counterparties that operate
different schemes.
5.4.4. Name
A locally unique (within the OU) identifier, which can identify the
application, project or individual developer responsible for this
client connection. This is the most granular unit of access control,
and gateways should ensure appropriate identifiers are used for the
needs of the application or use case.
5.4.5. Examples
satclient:quant/api.overledger.quant.com/research/luke.riley
5.5. Gateway Level Access Control
Gateways can enforce access rules based on standard naming
conventions using novel or existing mechanisms such as AuthZ
protocols using the resource identifiers above, for example:
satpclient://hsbc/api.overledger.hsbc.com/lending/eric.devloper
can READ/WRITE
satpres://quant/api.gateway1.com/tradelens
AND
satpres://quant/api.gateway1.com/ripple
These rules would allow a client so identified to access resources
directly, for example:
satpres://quant/api.gateway1.com/tradelens/xxxxxADDRESSxxxxx
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This method allows resource owners to easily grant access to
individuals, groups and organizations. Individual gateway
implementations may implement access controls, including subsetting
and supersetting or applications or resources according to their own
requirements.
5.6. Negotiation of Security Protocols and Parameters
5.6.1. TLS Established
TLS 1.2 or higher MUST be implemented to protect gateway
communications. TLS 1.3 or higher SHOULD be implemented where both
gateways support TLS 1.3 or higher.
5.6.2. Client offers supported credential schemes
Capability negotiation prior to data exchange, follows a scheme
similar to the Session Description Protocol [RFC 5939]. Initially
the client (application) sends a JSON block containing acceptable
credential schemes, e.g. OAuth2.0, SAML in the "Credential Scheme"
field of the SATP message.
5.6.3. Server selects supported credential scheme
The server (recipient Gateway) selects one acceptable credential
scheme from the offered schemes, returning the selection in the
"Credential Scheme" field of the SATP message.
If no acceptable credential scheme was offered, an HTPP 511 "Network
Authentication Required" error is returned in the Action/Response
field of the SATP message.
5.6.4. Client asserts or proves identity
The details of the assertion / verification step are specific to the
chosen credential scheme and are out of scope of this document.
5.6.5. Sequence numbers initialized
Sequence numbers are used to allow the server to correctly order
operations from the client, some of which may be asynchronous,
synchronous, idempotent with duplicate requests handled in different
ways according to the use case.
The initial sequence number is proposed by the client (sender
gateway) after the finalization of credential verification. The
server (recipient gateway) MUST respond with the same sequence number
to indicate acceptance.
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The client (sender gateway) increments the sequence number with each
new request. Sequence numbers can be reused for retries in the event
of a gateway timeout.
5.6.6. Messages can now be exchanged
Handshaking is complete at this point, and the client can send SAT
messages to perform actions on resources, which MAY reference the SAT
Payload field.
5.7. Asset Profile Identification
The client and server must mutually agree as to the asset type or
profile that is the subject to the current transfer from the client
and server. The client must provide the server with the asset-
identification number, or the server may provide the client with the
asset-identification numbers for the digital asset supported by the
server.
Formal specification of asset identification is out of scope of this
document. Global numbering of digital asset types or profiles is
expected to be performed by a legally recognized entity.
5.8. Application Profile Negotiation
Where an application relies on specific extensions for operation,
these can be represented in an Application Profile.
For example, a payments application tracks payments through the use
of a cloud based API and will only interact with gateways that log
messages to that API, a resource profile can be established:
Application Name: TRACKER
X-Tracker_URL: https://api.tracker.com/updates
X-Tracking-Policy: Always
As gateways implement this functionality, they support the TRACKER
application profile, and the application is able to expand its reach
by periodically polling for the availability of the profile.
This is an intentionally generalized extension mechanism for
application or vendor specific functionality.
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5.9. Discovery of Digital Asset Resources
Applications located outside a network or system SHOULD be able to
discover which resources they are authorized to access in a network
or system.
Resource discovery is handled by the gateway in front of the network.
For instance using a GET request against the gateway URL with no
resource identifier could return a list of URLs available to the
requester. This list is subject to the access controls above.
Gateways MAY allow applications to discover resources they do not
have access to. This should be indicated in the free text field, and
gateways SHOULD implement a process for applications to request
access.
Formal specification of supported resource discovery methods is out
of scope of this document.
6. Identity and Asset Verification Flow (Stage 0)
Prior to commencing the asset transfer from the sender gateway
(client) to the recipient gateway (server), both gateways must
perform a number of verifications steps. The types of information
required by both the sender and recipient are use-case dependent and
asset-type dependent.
The verifications include, but not limited to, the following:
* Gateway identity mutual verification: This is the identity of the
gateway at the protocol and network layer. This may include
validating the X509 certificates of the gateways.
* Gateway owner verification: This is the verification of the
identity (e.g. LEI) of the owners of the gateways.
* Gateway device and state validation: This is the device
attestation evidence [RATS] that a gateway must collect and convey
to each other, where a verifier is assumed to be available to
decode, parse and appraise the evidence.
* Originator and beneficiary identity verification: This is the
identity and public-key of the entity (originator) in the origin
network seeking to transfer the asset to another entity
(beneficiary) in the destination network.
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These are considered out of scope in the current specifications, and
are assumed to have been successfully completed prior to the
commencement of the transfer initiation flow.
7. Transfer Initiation and Commencement Flows (Stage 1)
This section describes the SATP Set-up stage, where a sender gateway
interacts with a recipient gateway, proposing a session.
These artifacst are contained in the Transfer Initiation Claims.
Gateways MUST support the use of the HTTP GET and POST methods
defined in RFC 2616 [RFC2616] for the endpoint.
Clients (sender gateway) MAY use the HTTP GET or POST methods to send
messages in this phase to the server (recipient gateway). If using
the HTTP GET method, the request parameters may be serialized using
URI Query String Serialization.
The client and server may be required to sign certain messages in
order to provide standalone proof (for non-repudiation) independent
of the secure channel between the client and server. This proof may
be required for audit verifications (e.g. post-event).
(NOTE: Flows occur over TLS. Nonces are not shown).
7.1. Transfer Initialization Claims
This is set of artifacts pertaining to the asset that must be agreed
upon between the client (sender gateway) and the server (recipient
gateway).
The Transfer Initialization Claims consists of the following:
* digital_asset_id: This is the globally unique identifier for the
digital asset located in the origin network.
* asset_profile_id: This is the globally unique identifier for the
asset-profile definition (document) on which the digital asset was
issued.
* verified_originator_entity_id: This is the identity data of the
originator entity (person or organization) in the origin network.
This information must be verified by the sender gateway.
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* verified_beneficiary_entity_id: This is the identity data of the
beneficiary entity (person or organization) in the destination
network. This information must be verified by the receiver
gateway.
* originator_pubkey REQUIRED. This is the public key of the asset
owner (originator) in the origin network or system.
* beneficiary_pubkey REQUIRED. This is the public key of the
beneficiary in the destination network.
* sender_gateway_network_id REQUIRED. This is the identifier of the
origin network or system behind the client.
* recipient_gateway_network_id REQUIRED. This is the identifier of
the destination network or system behind the server.
* client_identity_pubkey REQUIRED. The public key of client who
sent this message.
* server_identity_pubkey REQUIRED. The public key of server for
whom this message is intended.
* sender_gateway_owner_id: This is the identity information of the
owner or operator of the sender gateway.
* receiver_gateway_owner_id: This is the identity information of the
owner or operator of the recipient gateway.
7.2. Conveyance of Network Capabilities and Parameters
This is set of artifacts pertaining to the origin network behind the
client (sender gateway) that MAY be communicated to the server
(recipient gateway). A server may accept the asset-related claims
but reject the transfer request based on parameters of the origin
network.
Some of these parameters maybe gateway-specific (e.g. chosen
signature algorithm), while others are inherent in the origin network
(e.g. lock type; average lock duration time; etc.).
The network capabilities list is as follows:
* sender_gateway_network_id REQUIRED. This is the identifier of the
origin network or system behind the client.
* signature_algorithm REQUIRED: The digital signature algorithm
chosen by the client (sender gateway) for signing claims.
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* supported_signature_algorithm OPTIONAL: The list of algorithm-id
that is supported by the client from which the server MAY select.
* Lock_type REQUIRED: faucet, timelock, hashlock, hashtimelock,
multi-claim PC, destroy/burn (escrowed cross-claim).
* Lock_expiration_time REQUIRED: when will the lock or escrow
expire.
* Permissions OPTIONAL: list of identities (public-keys or X.509
certificates) that can perform operations on the escrow or lock on
the asset in the origin network.
* developer_URN OPTIONAL: Assertion of developer / application
identity.
* credential_profile REQUIRED: Specify type of auth (e.g. SAML,
OAuth, X.509).
* application_profile OPTIONAL: Vendor or Application specific
profile.
* logging_profile REQUIRED: contains the profile regarding the
logging procedure. Default is local store
* Access_control_profile REQUIRED: the profile regarding the
confidentiality of the log entries being stored. Default is only
the gateway that created the logs can access them.
* Subsequent calls OPTIONAL: details possible escrow actions.
* History OPTIONAL: provides an history of the escrow, in case it
has previously been initialized.
7.3. Transfer Proposal Message
The purpose of this message is for the client to initiate an asset
Transfer and propose the set of claims related to the asset to be
transferred. This message must be signed by the client.
Depending on the proposal, multiple rounds of communication between
the client and the server may occur.
This message is sent from the client to the Transfer Initialization
Endpoint at the server.
The parameters of this message consists of the following:
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* version REQUIRED: SAT protocol Version (major, minor).
* message_type REQUIRED: urn:ietf:satp:msgtype:init-proposal-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen by the
client to identify the current session.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* transfer_init_claims: The set of artifacts and parameters as the
basis for the current transfer.
* transfer_init_claims_format OPTIONAL: The format of the transfer
initialization claims.
* network_capabilities_list REQUIRED: The set of origin network
parameters reported by the client to the server.
* client_identity_pubkey REQUIRED. The public key of client who
sent this message.
* server_identity_pubkey REQUIRED. The public key of server for
whom this message is intended.
* multiple_claims_allowed OPTIONAL: true/false.
* multiple_cancels_allowed OPTIONAL: true/false.
* client signature REQUIRED: The client's signature over the
message.
7.4. Transfer Proposal Receipt Message
The purpose of this message is for the server to indicate explicit
acceptance of the Transfer Initialization Claims in the transfer
proposal message.
The message must be signed by the server.
The message is sent from the server to the Transfer Proposal Endpoint
at the client.
The parameters of this message consists of the following:
* version REQUIRED: SAT protocol Version (major, minor).
* message_type REQUIRED: urn:ietf:satp:msgtype:init-receipt-msg
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* session_id REQUIRED: A unique identifier (UUIDv2) chosen by the
client to identify the current session.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* hash_transfer_init_claims REQUIRED: Hash of the Transfer
Initialization Claims received in the Transfer Proposal Message.
* Timestamp REQUIRED: timestamp referring to when the Initialization
Request Message was received.
Example: TBD.
7.5. Transfer Proposal Reject and Conditional Reject Message
The purpose of this message is for the server to indicate a rejection
or conditional rejection of the Transfer Initialization Claims. In
the case of a conditional rejection, the server may propose a
different set of claims (counter-proposal claims) to the client.
If the server wishes to indicate a conditional rejection, the server
MUST include a counter-proposal set of claims.
If the server does not wish to proceed, the server MUST include an
empty (blank) counter-proposal.
Depending on the proposal and counter-proposal, multiple rounds of
communication between the client and the server may occur.
The message must be signed by the server.
The message is sent from the server to the Transfer Proposal Endpoint
at the client.
The parameters of this message consists of the following:
* version REQUIRED: SAT protocol Version (major, minor).
* message_type REQUIRED: urn:ietf:satp:msgtype:init-reject-msg
* session_id REQUIRED: A unique identifier (UUIDv2) chosen by the
client to identify the current session.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
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* hash_transfer_init_claims REQUIRED: Hash of the Transfer
Initialization Claims received in the Transfer Proposal Message.
* transfer_init_counter_claims: The set of artifacts and parameters
as the counter-proposal to the client.
* Timestamp REQUIRED: timestamp referring to when the Initialization
Request Message was received.
Example: TBD.
7.6. Transfer Commence Message
The purpose of this message is for the client to signal to the server
that the client is ready to start the transfer of the digital asset.
This message must be signed by the client.
This message is sent by the client as a response to the Transfer
Proposal Receipt Message previously receuved from the server.
This message is sent by the client to the Transfer Commence Endpoint
at the server.
The parameters of this message consists of the following:
* message_type REQUIRED. MUST be the value
urn:ietf:satp:msgtype:transfer-commence-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The public key of client who
sent this message.
* server_identity_pubkey REQUIRED. The public key of server for
whom this message is intended.
* hash_transfer_init_claims REQUIRED: Hash of the Transfer
Initialization Claims received in the Transfer Proposal Message.
* hash_prev_message REQUIRED. The hash of the last message, in this
case the Transfer Proposal Receipt message.
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* client_transfer_number OPTIONAL. This is the transfer
identification number chosen by the client. This number is
meaningful only the client.
* client_signature REQUIRED. The digital signature of the client.
For example, the client makes the following HTTP request using TLS
(with extra line breaks for display purposes only):
POST /token HTTP/1.1
Host: server.example.com
Authorization: Basic awHCaGRSa3F0MzpnWDFmQmF0M2ZG
Content-Type: application/x-www-form-urlencoded
{
"message_type": "urn:ietf:satp:msgtype:transfer-commence-msg",
"session_id":"9097hkstgkjvVbNH",
"originator_pubkey":"zGy89097hkbfgkjvVbNH",
"beneficiary_pubkey": "mBGHJjjuijh67yghb",
"sender_net_system": "originNETsystem",
"recipient_net_system":"recipientNETsystem",
"client_identity_pubkey":"fgH654tgeryuryuy",
"server_identity_pubkey":"dFgdfgdfgt43tetr535teyrfge4t54334",
"transfer_init_claims":"nbvcwertyhgfdsertyhgf2h3v4bd3v21",
"hash_prev_message":"DRvfrb654vgreDerverv654nhRbvder4",
"client_transfer_number":"ji9876543ewdfgh",
"client_signature":"fdw34567uyhgfer45"
}
Figure 2
7.7. Commence Response Message (ACK-Commence)
The purpose of this message is for the server to indicate agreement
to proceed with the asset transfer, based on the artifacts found in
the previous Transfer Proposal Message.
This message is sent by the server to the Transfer Commence Endpoint
at the client.
The message must be signed by the server.
The parameters of this message consists of the following:
* message_type REQUIRED urn:ietf:satp:msgtype:ack-commence-msg
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* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client for whom this message
is intended.
* server_identity_pubkey REQUIRED. The server who sent this
message.
* hash_prev_message REQUIRED. The hash of the last message, in this
case the the Transfer Commence Message.
* server_transfer_number OPTIONAL. This is the transfer
identification number chosen by the server. This number is
meaningful only to the server.
* server_signature REQUIRED. The digital signature of the server.
An example of a success response could be as follows: (TBD)
8. Lock Assertion and Receipt (Stage 2)
The messages in this stage pertain to the sender gateway providing
the recipient gateway with a signed assertion that the asset in the
origin network has been locked or disabled and under the control of
the sender gateway.
In the following, the sender gateway takes the role of the client
while the recipient gateway takes the role of the server.
The flow follows a request-response model. The client makes a
request (POST) to the Lock-Assertion Endpoint at the server.
Gateways MUST support the use of the HTTP GET and POST methods
defined in RFC 2616 [RFC2616] for the endpoint.
Clients MAY use the HTTP GET or POST methods to send messages in this
phase to the server. If using the HTTP GET method, the request
parameters may be serialized using URI Query String Serialization.
(NOTE: Flows occur over TLS. Nonces are not shown).
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8.1. Lock Assertion Message
The purpose of this message is for the client (sender gateway) to
convey a signed claim to the server (receiver gateway) declaring that
the asset in question has been locked or escrowed by the client in
the origin network (e.g. to prevent double spending).
The format of the claim is dependent on the network or system of the
client and is outside the scope of this specification.
This message is sent from the client to the Lock Assertion Endpoint
at the server.
The server must validate the claims (payload) in this message prior
to the next step.
The message must be signed by the client.
The parameters of this message consists of the following:
* message_type REQUIRED urn:ietf:satp:msgtype:lock-assert-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client who sent this
message.
* server_identity_pubkey REQUIRED. The server for whom this message
is intended.
* lock_assertion_claim REQUIRED. The lock assertion claim or
statement by the client.
* lock_assertion_claim_format REQUIRED. The format of the claim.
* lock_assertion_expiration REQUIRED. The duration of time of the
lock or escrow upon the asset.
* hash_prev_message REQUIRED. The hash of the previous message.
* client_transfer_number OPTIONAL. This is the transfer
identification number chosen by the client. This number is
meaningful only to the client.
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* client_signature REQUIRED. The digital signature of the client.
8.2. Lock Assertion Receipt Message
The purpose of this message is for the server (receiver gateway) to
indicate acceptance of the claim(s) in the lock-assertion message
delivered by the client (sender gateway) in the previous message.
This message is sent from the server to the Assertion Receipt
Endpoint at the client.
The message must be signed by the server.
The parameters of this message consists of the following:
* message_type REQUIRED urn:ietf:satp:msgtype:assertion-receipt-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client for whom this message
is intended.
* server_identity_pubkey REQUIRED. The server who sent this
message.
* hash_prev_message REQUIRED. The hash of previous message.
* server_transfer_number OPTIONAL. This is the transfer
identification number chosen by the server. This number is
meaningful only to the server.
* server_signature REQUIRED. The digital signature of the server.
9. Commitment Preparation and Finalization (Stage 3)
This section describes the transfer commitment agreement between the
client (sender gateway) and the server (receiver gateway).
This phase must be completed within the time specified in the
lock_assertion_expiration value in the lock-assertion message.
In the following, the sender gateway takes the role of the client
while the recipient gateway takes the role of the server.
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The flow follows a request-response model. The client makes a
request (POST) to the Transfer Commitment endpoint at the server.
Gateways MUST support the use of the HTTP GET and POST methods
defined in RFC 2616 [RFC2616] for the endpoint.
Clients MAY use the HTTP GET or POST methods to send messages in this
phase to the server. If using the HTTP GET method, the request
parameters maybe serialized using URI Query String Serialization.
The client and server may be required to sign certain messages in
order to provide standalone proof (for non-repudiation) independent
of the secure channel between the client and server. This proof
maybe required for audit verifications post-event.
(NOTE: Flows occur over TLS. Nonces are not shown).
9.1. Commit Preparation Message (Commit-Prepare)
The purpose of this message is for the client to indicate its
readiness to begin the commitment of the transfer.
This message is sent from the client to the Commit Prepare Endpoint
at the server.
The message must be signed by the client.
The parameters of this message consists of the following:
* message_type REQUIRED. It MUST be the value
urn:ietf:satp:msgtype:commit-prepare-msg
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client who sent this
message.
* server_identity_pubkey REQUIRED. The server for whom this message
is intended.
* hash_prev_message REQUIRED. The hash of previous message.
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* client_transfer_number OPTIONAL. This is the transfer
identification number chosen by the client. This number is
meaningful only the client.
* client_signature REQUIRED. The digital signature of the client.
9.2. Commit Ready Message (Commit-Ready)
The purpose The purpose of this message is for the server to indicate
to the client that: (i) the server has created (minted) an equivalent
asset in the destination network; (ii) that the newly minted asset
has been self-assigned to the server; and (iii) that the server is
ready to proceed to the next step.
This message is sent from the server to the Commit Ready Endpoint at
the client.
The message must be signed by the server.
The parameters of this message consists of the following:
* message_type REQUIRED. It MUST be the value
urn:ietf:satp:msgtype:commit-ready-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client for whom this message
is intended.
* server_identity_pubkey REQUIRED. The server who sent this
message.
* mint_assertion_claims REQUIRED. The mint assertion claim or
statement by the server.
* mint_assertion_format OPTIONAL. The format of the assertion
payload.
* hash_prev_message REQUIRED. The hash of previous message.
* server_transfer_number OPTIONAL. This is the transfer
identification number chosen by the server. This number is
meaningful only the server.
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* server_signature REQUIRED. The digital signature of the server.
9.3. Commit Final Assertion Message (Commit-Final)
The purpose of this message is for the client to indicate to the
server that the client (sender gateway) has completed the
extinguishment (burn) of the asset in the origin network.
The message must contain standalone claims related to the
extinguishment of the asset by the client. The standalone claim must
be signed by the client.
This message is sent from the client to the Commit Final Assertion
Endpoint at the server.
The message must be signed by the server.
The parameters of this message consists of the following:
* message_type REQUIRED. It MUST be the value
urn:ietf:satp:msgtype:commit-final-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client who sent this
message.
* server_identity_pubkey REQUIRED. The server for whom this message
is intended.
* burn_assertion_claim REQUIRED. The burn assertion signed claim or
statement by the client.
* burn_assertion_claim_format OPTIONAL. The format of the claim.
* hash_prev_message REQUIRED. The hash of previous message.
* client_transfer_number OPTIONAL. This is the transfer
identification number chosen by the client. This number is
meaningful only the client.
* client_signature REQUIRED. The digital signature of the client.
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9.4. Commit-Final Acknowledgement Receipt Message (ACK-Final-Receipt)
The purpose of this message is to indicate to the client that the
server has completed the assignment of the newly minted asset to the
intended beneficiary at the destination network.
This message is sent from the server to the Commit Final Receipt
Endpoint at the client.
The message must be signed by the server.
The parameters of this message consists of the following:
* message_type REQUIRED. It MUST be the value
urn:ietf:satp:msgtype:ack-commit-final-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client for whom this message
is intended..
* server_identity_pubkey REQUIRED. The server who sent this
message.
* assignment_assertion_claim REQUIRED. The claim or statement by
the server that the asset has been assigned by the server to the
intended beneficiary.
* assignment_assertion_claim_format OPTIONAL. The format of the
claim.
* hash_prev_message REQUIRED. The hash of previous message.
* server_transfer_number OPTIONAL. This is the transfer
identification number chosen by the server. This number is
meaningful only the server.
* server_signature REQUIRED. The digital signature of the server.
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9.5. Transfer Complete Message
The purpose of this message is for the client to indicate to the
server that the asset transer session (identified by session_id) has
been completed and that no further messages are to be expected from
the client in regards to this transfer instance.
The message closes the first message of Stage 2 (Transfer Commence
Message).
This message is sent from the client to the Transfer Complete
Endpoint at the server.
The message must be signed by the client.
The parameters of this message consists of the following:
* message_type REQUIRED. It MUST be the value
urn:ietf:satp:msgtype:commit-transfer-complete-msg.
* session_id REQUIRED: A unique identifier (UUIDv2) chosen earlier
by client in the Initialization Request Message.
* transferContext_id OPTIONAL: An optional identifier (UUIDv2) used
to identify the current transfer session at the application layer.
* client_identity_pubkey REQUIRED. The client who sent this
message.
* server_identity_pubkey REQUIRED. The server for whom this message
is intended.
* hash_prev_message REQUIRED. The hash of previous message.
* hash_transfer_commence REQUIRED. The hash of the Transfer
Commence message at the start of Stage 2.
* client_transfer_number OPTIONAL. This is the transfer
identification number chosen by the client. This number is
meaningful only the client.
* client_signature REQUIRED. The digital signature of the client.
10. SATP Session Resumption
This section answers the question how can a backup gateway build
trust with the counter party gateway to resume the execution of the
protocol, in the presence of errors and crashes?
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Gateways may enter faulty state at any time while execution the
protocol. The faulty state can manifest itself by incorrect
behaviour, leading to gateways emitting alerts and errors.
In some instances, gateways may crash. We employ either the primary-
backup or self-healing paradigm, meaning that the crashed gateway
will eventually be replaced by a functioning one, or recover,
respectively.
When a crash occurs, we initiate a recovery procedure by the backup
gateway or the recovered gateway, as defined in the crash recovery
draft [draft-belchior-gateway-recovery-05]. In either case, if the
recovery happens within a time period d efined as max_timeout (in
Stage 2), the recovered gateway triggers a session resumption. The
schema and order of the recovered messages is specified in the crash
recovery draft.
In the case where there is no answer from the gateway within the
specified max_timeout, the counter-party gateway rollbacks the
process until that stage. Upon recovery, the crashed gateway learns
that the counterparty gateway has initated a rollback, and it
proceeds accordingly (by also initating a rollback). Note that
rollbacks can also happen in case of unresolved errors.
The non-crashed gateway that conducts the rollback tries to
communicate with the crashed gateway from time to time (self healing)
or to contact the backup gateways (primary-backup). In any case, and
upon the completion of a rollback, the non-crashed gateway sends a
ROLLBACK message to the recovered gateway to notify that a rollback
happened. The recovered gateway should answer with ROLLBACK-ACK.
Since the self-healing recovery process does not require changes to
the protocol (since from the counterparty gateway perspective, the
sender gateway is just taking longer than normal; there are no new
actions done or logs recorded), we focus on the primary-backup
paradigm.
10.1. Primary-Backup Session Resumption
Upon a gateway recovering using primary-backup, a new gateway
(recovered gateway) takes over the crashed gateway. The counter-
party gateway assures that the recovered gateway is legitimate
(according to the crash recovery specification).
After the recovery, the gateways exchange information about their
current view of the protocol, since the crashed gateway may have been
in the middle of executing the protocol when it crashed.
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After that, the gateways agree on the current state of the protocol.
10.2. Recovery Messages
We have omitted the logging procedure (only focusing the different
messages). As defined in the crash recovery draft [draft-belchior-
gateway-recovery-05], there are a set of messages that are exchanged
between the recovered gateway and counterparty gateway:
* RECOVER: when a gateway crashes and recovers, it sends a RECOVER
message to the counterparty gateway, informing them of its most
recent state. The message contains various parameters such as the
session ID, message type, SATP phase, sequence number, a flag
indicating if the sender is a backup gateway, the new public key
if the sender is a backup, the timestamp of the last known log
entry, and the sender's digital signature.
* RECOVER-UPDATE: Upon receiving the RECOVER message, the
counterparty gateway sends a RECOVER-UPDATE message. This message
carries the difference between the log entry corresponding to the
received sequence number from the recovered gateway and the latest
sequence number (corresponding to the latest log entry). The
message includes parameters such as the session ID, message type,
the hash of the previous message, the list of log messages that
the recovered gateway needs to update, and the sender's digital
signature.
* RECOVER-SUCCESS: The recovered gateway responds with a RECOVER-
SUCCESS message if its logs have been successfully updated. If
there are inconsistencies detected, the recovered gateway
initiates a dispute with a RECOVER-DISPUTE message. The message
parameters include session ID, message type, the hash of the
previous message, a boolean indicating success, a list of hashes
of log entries that were appended to the recovered gateway log,
and the sender's digital signature.
In case the recovery procedure has failed and a rollback process is
needed, the following messages are used:
* ROLLBACK: A gateway that initiates a rollback sends a ROLLBACK
message. The message parameters include session ID, message type,
a boolean indicating success, a list of actions performed to
rollback a state (e.g., UNLOCK, BURN), a list of proofs specific
to the DLT [SATP], and the sender's digital signature.
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* ROLLBACK-ACK: Upon successful rollback, the counterparty gateway
sends a ROLLBACK-ACK message to the recovered gateway
acknowledging that the rollback has been performed successfully.
The message parameters are similar to those of the ROLLBACK
message.
11. Error Messages
SATP SATP distinguishes between application driven closures
(terminations) and those caused by errors at the SATP protocol level.
The list of errors and desciption can be found in the Appendix.
enum { session_closure(1), nonfatal_error (2) fatal_error(3), (255) } AlertLevel;
enum {
close_notify(0),
bad_certificate(42),
unsupported_certificate(43),
certificate_revoked(44),
certificate_expired(45),
certificate_unknown(46),
illegal_parameter(47),
TBD
(255)
} AlertDescription;
struct {
AlertLevel level;
AlertDescription description;
} Alert;
Figure 3
11.1. Closure Alerts
The SATP client and server (gateways) must share knowledge that the
transfer connection is ending in order to avoid third party attacks.
(a) close_notify: This alert notifies the recipient that the sender
gateway will not send any more messages on this transfer connection.
Any data received after a closure alert has been received MUST be
ignored.
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(b) user_canceled: This alert notifies the recipient that the sender
gateway is canceling the transfer connection for some reason
unrelated to a protocol failure.
11.2. Error Alerts
When an error is detected by a SATP gateway, the detecting gateway
sends a message to its peer.
Upon transmission or receipt of a fatal alert message, both gateways
MUST immediately close the connection. Whenever a SATP
implementation encounters a fatal error condition, it SHOULD send an
appropriate fatal alert and MUST close the connection without sending
or receiving any additional data.
The following error alerts are defined:
* connection_error: There is an error in the TLS session
establishment (TLS error codes should be reported-up to gateway
level)
* bad_certificate: The gateway certificate was corrupt, contained
signatures, that did not verify correctly, etc. (Some common TLS
level errors: unsupported_certificate, certificate_revoked,
certificate_expired, certificate_unknown, unknown_ca).
* protocol_version_error: The SATP protocol version the peer has
attempted to negotiate is recognized but not supported.
* (Others TBD)
12. Security Consideration
Gateways are of particular interest to attackers because they are a
kind of end-to-end pipeline that enable the transferral of digital
assets to external networks or systems. Thus, attacking a gateway
may be attractive to attackers instead of the network behind a
gateway.
As such, hardware hardening technologies and tamper-resistant crypto-
processors (e.g. TPM, Secure Enclaves, SGX) should be considered for
implementations of gateways.
13. IANA Consideration
(TBD)
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14. Appendix A: Error Types
The following lists the error associated with each message in SATP.
(Note: these have been laid out for convenience, and may be grouped
together more efficiently later).
14.1. Transfer Commence and Response errors
The following are the list of errors related to Transfer Commence and
Response:
* [err_2.1] Badly formed message.
* [err_2.2] Incorrect parameter.
* [err_2.3] ACK mismatch.
14.2. Lock Assertion errors
The following are the list of errors related to Lock Assertion:
* [err_2.4.1] Badly formed message: badly formed Claim.
* [err_2.4.2] Badly formed message: bad signature.
* [err_2.4.3] Badly formed message: wrong transaction ID.
* [err_2.4.4] Badly formed message: Mismatch hash values.
* [err_2.4.5] Expired signing-key certificate.
* [err_2.4.6] Expired Claim.
14.3. Lock Assertion Receipt errors
The following are the list of errors related to Lock Assertion
Receipt:
* [err_2.6.1] Badly formed message: badly formed Claim.
* [err_2.6.2] Badly formed message: bad signature.
* [err_2.6.3] Badly formed message: wrong transaction ID.
* [err_2.6.4] Badly formed message: Mismatch hash values.
* [err_2.6.5] Expired signing-key certificate.
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* [err_2.6.6] Expired Claim.
14.4. Commit Preparation errors
The following are the list of errors related to Commit Preparation:
* [err_3.1.1] Badly formed message: wrong transaction ID.
* [err_3.1.2] Badly formed message: mismatch hash value (i.e. from
msg 2.6).
* [err_3.1.3] Incorrect parameter.
* [err_3.1.4] Message out of sequence.
14.5. Commit Preparation Acknowledgement errors
The following are the list of errors related to Commit Preparation
Acknowledgement:
* [err_3.2.1] Badly formed message: wrong transaction ID.
* [err_3.2.2] Badly formed message: mismatch hash value.
* [err_3.2.3] Incorrect parameter.
* [err_3.2.4] Message out of sequence.
14.6. Commit Ready errors
The following are the list of errors related to Commit Ready:
* [err_3.4.1] Badly formed message: wrong transaction ID.
* [err_3.4.2] Badly formed message: mismatch hash value.
* [err_3.4.3] Incorrect parameter.
* [err_3.4.4] Message out of sequence (ACK mismatch).
14.7. Commit Final Assertion errors
The following are the list of errors related to Commit Final
Assertion:
* [err_3.6.1] Badly formed message: badly formed Claim.
* [err_3.6.2] Badly formed message: bad signature.
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* [err_3.6.3] Badly formed message: wrong transaction ID.
* [err_3.6.4] Badly formed message: Mismatch hash values.
* [err_3.6.5] Expired signing-key certificate.
* [err_3.6.6] Expired Claim.
15. References
15.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, DOI 10.17487/RFC2234,
November 1997, <https://www.rfc-editor.org/info/rfc2234>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>.
15.2. Informative References
[draft-belchior-gateway-recovery-05]
Belchior, R., Correia, M., Augusto, A., and T. Hardjono,
"DLT Gateway Crash Recovery Mechanism", Work in Progress,
Internet-Draft, draft-belchior-gateway-recovery-05, 19
April 2023, <https://datatracker.ietf.org/doc/html/draft-
belchior-gateway-recovery-05>.
[NIST] Yaga, D., Mell, P., Roby, N., and K. Scarfone, "NIST
Blockchain Technology Overview (NISTR-8202)", October
2018, <https://doi.org/10.6028/NIST.IR.8202>.
[RFC5939] Andreasen, F., "Session Description Protocol (SDP)
Capability Negotiation", RFC 5939, DOI 10.17487/RFC5939,
September 2010, <https://www.rfc-editor.org/info/rfc5939>.
Authors' Addresses
Martin Hargreaves
Quant Network
Email: martin.hargreaves@quant.network
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Thomas Hardjono
MIT
Email: hardjono@mit.edu
Rafael Belchior
Technico Lisboa
Email: rafael.belchior@tecnico.ulisboa.pt
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