CORE Working Group                                           P. Urien
  Internet Draft                                      Telecom ParisTech
  Intended status: Experimental

                                                           June 14 2020
  Expires: December 2020

               Blockchain Transaction Protocol for Constraint Nodes
              draft-urien-core-blockchain-transaction-protocol-04.txt


Abstract

   The goal of the blockchain transaction protocol for constraint nodes
   is to enable the generation of blockchain transactions by constraint
   nodes, according to the following principles:
   - transactions are triggered by Provisioning-Messages that include
   the needed blockchain parameters.
   - binary encoded transactions are returned in Transaction-Messages,
   which include sensors/actuators data. Constraint nodes, associated
   with blockchain addresses, compute the transaction signature.

Requirements Language

   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.

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
   Task Force (IETF). Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six
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   at any time. It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 2020.

   .







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Table of Contents
   Abstract........................................................... 1
   Requirements Language.............................................. 1
   Status of this Memo................................................ 1
   Copyright Notice................................................... 2
   1 Overview......................................................... 4
   2 Overview of the Blockchain Transaction Protocol for Constraint
   Nodes.............................................................. 4
      2.1 Architecture................................................ 4
      2.2 An Ethereum Use Case........................................ 5
   3 Blockchain Transaction Protocol Messages Definition.............. 6
      3.1 Provisioning Message........................................ 6
          3.1.1 Encoding example in JSON syntax ...................... 6
      3.2 Transaction Message......................................... 6
          3.2.1 Encoding example in JSON syntax ...................... 6
   4. Blockchain Transaction Protocol Messages Binary Encoding........ 7
      4.1 CoAP messages............................................... 7
      4.2 HTTP Messages............................................... 7
   5 IANA Considerations.............................................. 7
   6 Security Considerations.......................................... 7
   6 References....................................................... 7
      6.1 Normative References........................................ 7
      6.2 Informative References...................................... 7
   7 Authors' Addresses............................................... 7




























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1 Overview

   In the context of this draft sensors/actuators are powered by micro-
   controllers comprising about 10KB of RAM and 100KB of non volatile
   memory. The node electronic board may include a radio SoC (System On
   Chip) or the micro-controller can be part of the SoC. The radio chip
   manages IP connectivity with another device, typically acting as a
   controller, which provides a full internet access with standard
   computing resources.

   A constraint node driving sensors and/or actuators may deliver
   critical data dealing with safety (fire detection,...) or legacy
   (pollution measurement,...) information.

   Blockchain infrastructure provides two important features in an
   Internet of Things (IoT) context:

   - Authentication of data in P2P context. Blockchain signed
   transactions are checked by numerous nodes.
   - Information publication. Transactions are stored in duplicated and
   distributed databases.
   - Dating information. Transactions are dated during the mining
   process.

   The goal of the blockchain transaction protocol for constraint nodes
   is to enable the generation of blockchain transactions by constraint
   nodes, according to the following principles:
   - transactions are triggered by controllers. Needed blockchain
   parameters are included in provisioning messages.
   - binary encoded transaction messages are returned by constraint
   nodes. A node has the ability to compute the transaction signature.


2 Overview of the Blockchain Transaction Protocol for Constraint Nodes

2.1 Architecture

                    <--Provisioning-Message
   +--------------------+  IP  +----------------------+  +------------+
   |  Constraint Node   | link |      Controller      |  | Blockchain |
   + Blockchain Address +------+ Full IP connectivity +--+   Network  |
   +    Private Key     |      | Access to blockchain |  |            |
   +--------------------+      +----------------------+  +------------+
                     Transaction-Message-->

   Figure 1. Functional architecture for the Blockchain Transaction
   Protocol for Constraint Nodes

   A constraint node holds a blockchain address (BA). The blockchain
   address is computed from a private key (Pk). Most of today
   blockchain infrastructures deal with ECDSA signatures, generated

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   over the Secp256k1 elliptic curve. The private key is a 32 bytes
   number, stored in the constraint node. The computation of hash
   procedures such a SHA2 or KECCAK-256 can be handled by
   microcontrollers. Although ECDSA signature may be generated by a
   microcontroller, a tamper resistant resource could be used, either
   embedded in the CPU, or in a chip such as a secure element[ISO7816].
   As an illustration an architecture based on micro-controller, radio
   SoC and secure element was demonstrated in [IEEE-CCNC2018].

   The controller is a device with full IP connectivity. It typically
   communicates with the constraint node thanks to the CoAP [RFC7252]
   protocol, or other legacy protocols such as HTTPS. The controller
   has access to the blockchain infrastructure, to which it is able to
   forward a binary encoded transaction, signed by the constraint node.

2.2 An Ethereum Use Case.

   The following figure 2, illustrates an Ethereum transaction
   generated by a constraint node, whose total length is 118 bytes.

   F8 74 // RLP List, length= 116 bytes
   0C // nonce 1 byte =12 decimal
   85 06FC23AC00 // gasPrice = 30 GWei
   83 013880     // gasLimit = 80000 gas
   // recipient address 20 bytes
   94 6BAC1B75185D9051AF740AB909F81C71BBB221A6
   80 // Null Ether Value
   // Data 15 bytes "Temperature=25C"
   8F 54656D70657261747572653D323543
   1B // recovery parameter, 1 byte
   A0 // r, 32 bytes, ECDSA r parameter
   A9B58980F76EE6284800B82A2B5DF13E456887EC0CF426A5E5D6A738EB1784ED
   A0 // s, 32 bytes, ECDSA s parameter
   629633C6A3ED5FEE0FB40E2D1CF251345B885D372857B1A6C4762C9BE914281F

   Figure 2. Illustration of an Ethereum transaction, generated by a
   constraint node.

   The identifier (TxId) of this transaction (i.e. its KECCAK-256
   digest) is:

   0xd6904d832462ae17718c69e9caa0c3f3bed458382ac1f4e43b1aadd8e94744ad

   Given this TxId, the transaction can be retrieved in any Ethereum
   blockchain database, like for example:

   https://etherscan.io/tx/0xd6904d832462ae17718c69e9caa0c3f3bed458382a
   c1f4e43b1aadd8e94744ad

   The transaction date (20-2018 09:52:42 PM +UTC) is published and
   certified by the blockchain.

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   The binary encoded transaction comprises two parts,
   - information relying on the Ethereum blockchain context, such as
   the nonce, the gasPrice, the gasLimit, the recipient address, and an
   Ether value.
   - information delivered by the constraint node, data (a temperature
   measurement), and the ECDSA signature computed from the 32 bytes
   private key.

   Parameters relying on the Ethereum blockchain context MUST be
   included in the Provisioning-Message.
   The signed transaction MUST be included in the Transaction-Message.

3 Blockchain Transaction Protocol Messages Definition

   The Blockchain Transaction Protocol comprises two messages, to be
   included in transport protocols, such as CoAP or HTTP.

3.1 Provisioning Message

   This message includes the following attributes :
   - A type, an integer value, specifying the message content.
   - An ordered list of values, storing the parameters of the
   blockchain context.

  3.1.1 Encoding example in JSON syntax

   Here is an illustration of the provisioning message associated to
   the Ethereum blockchain.

   {
     "type": 1,
     "nonce": 12,
     "gasPrice": 30,
     "gasLimit": 80000,
     "address": "6BAC1B75185D9051AF740AB909F81C71BBB221A6",
     "value": 0
   }

3.2 Transaction Message

   This message include the following attributes
   - A type, an integer value, specifying the message content. The zero
   value indicates an error.
   - The binary encoded transaction, including the signature.

  3.2.1 Encoding example in JSON syntax

   Here is an illustration of the transaction message associated to the
   Ethereum blockchain.



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   {
     "type": 1,
     "transaction":
   "F8740C8506FC23AC0083013880946BAC1B75185D9051AF740AB909F81C71BBB221A
   6808F54656D70657261747572653D3235431BA0A9B58980F76EE6284800B82A2B5DF
   13E456887EC0CF426A5E5D6A738EB1784EDA0629633C6A3ED5FEE0FB40E2D1CF2513
   45B885D372857B1A6C4762C9BE914281F"
   }

4. Blockchain Transaction Protocol Messages Binary Encoding

4.1 CoAP messages

   To be Done

4.2 HTTP Messages

   To be Done

5 IANA Considerations

   TODO

6 Security Considerations

   TODO

6 References

6.1 Normative References

   [RFC7252]  Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
   Application Protocol (CoAP)", RFC 7252, June 2014.

   [ISO7816] ISO 7816, "Cards Identification - Integrated Circuit Cards
   with Contacts", The International Organization for Standardization
   (ISO).

6.2 Informative References

   [IEEE-CCNC2018] Urien,P., "An Innovative Security Architecture for
   Low Cost Low Power IoT Devices Based on Secure Elements", IEEE CCNC
   2018

7 Authors' Addresses

   Pascal Urien
   Telecom ParisTech
   23 avenue d'Italie
   75013 Paris               Phone: NA
   France                    Email: Pascal.Urien@telecom-paristech.fr

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