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Open Registry for IoT: Smart Contracts

This open source project represents Ethereum smart contracts which are at the essence of Open Registry for IoT. You can find contracts in /contracts directory.

  • Registrar — whitelisting contract, stores all Registrants which are allowed to add new Things to the registry.
  • Registry — registry itself, stores identities and information about all Things added.

Separate repository provides SDK which gives clear interface to the contracts for JavaScript.

Install Dependencies

$ npm install -g truffle
$ npm install -g ethereumjs-testrpc

Test contracts

$ testrpc
$ truffle test

URN Specification

Draft

In the Open Registry, all Things have identities. We have adopted a Uniform Resource Name (URN) standard format to represent these identities, ranging from cryptographic public keys to BLE & NFC device IDs. The URN format is easily readable and allows for the support of a wide variety of identities. It complies with current standards for representing products, books, electronics, etc., and can be used to identify literally anything without need to specify schema / protocol this identity can reached by. This extensibility is essential for building a universal and open platform for the Internet of Things.

Format

Each identity will be split by : into multiple sections, denoting more specific information about the identity after each subsequent colon. The last section denotes the actual identity of the Thing.

<Category>[:<Subcategory>[:<sub-Subcategory> … ]]:<ID>

All categories are case-insensitive.

Examples

BLE

ble:1.0:0A153C993D9C

NFC

nfc:1.0:04062782DF4980

Electronic Product Code: Serialized Global Trade Item Number

epc:id:sgtin:0614141.012345.62852

Serial number

sn:C02EK02HG8DL

Elliptic Curve Public Key

pbk:ec:secp256r1:0260fed4ba255a9d31c961eb74c6356d68c049b8923b61fa6ce669622e60f29fb6

RSA public key

pbk:rsa:2048: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

Construction of Public Key

Public Key

pbk

Elliptic Curve Public Key

pbk:ec

RSA Public Key

pbk:rsa

Elliptic curve using verified random parameters

pbk:ec:secp256r1

Full ECC URN

pbk:ec:secp256r1:0260fed4ba255a9d31c961eb74c6356d68c049b8923b61fa6ce669622e60f29fb6

Elliptic Curve Public Key

Asymmetric encryption public key is stored in open registry to securely verify authenticity identity of a Thing using by means of cryptographic signature.

From Raw ECC Public Key to Identity in the Open Registry

Here we will illustrate an example how to convert an uncompressed public key into URN identity to be stored in the Open Registry. Its assumed that you have already generated your ECC key pair.

The public key is represented as a point (x,y) on an elliptic curve. Convert point coordinates into their hexadecimal representations. For this example we will use the following point: x=0x7462163f89fc02b989e564cf7a2ce39a806273ee4042201fb5544cc794c48975 y=0xd53acb27ef5da1cba6ff90e3611637e55a14ce6a9ec25063cd0de943f1dd3b04

Representation

We're using format suggested in https://www.ietf.org/rfc/rfc5480.txt Uncompressed public keys: mark the first octet with 0x04 Compressed public keys: mark the first octet with the correct polarity byte 0x02, 0x03 depending on the polarity of the y coordinate (explained below).

The public key in an uncompressed representation is then: 047462163f89fc02b989e564cf7a2ce39a806273ee4042201fb5544cc794c48975d53acb27ef5da1cba6ff90e3611637e55a14ce6a9ec25063cd0de943f1dd3b04

Converting into URN Format

Before the uncompressed public key can be registered to the Open Registry, it must be converted into the correct URN format as described above. Since we are using ECC's secp256r1 standard, the URN prefix is pbk:ec:secp256r1.

Resulting URN:

pbk:ec:secp256r1:047462163f89fc02b989e564cf7a2ce39a806273ee4042201fb5544cc794c48975d53acb27ef5da1cba6ff90e3611637e55a14ce6a9ec25063cd0de943f1dd3b04

Open Registry SDK

From here, the URN is fed into the Open Registry SDK. Here, it is parsed, compressed, and packaged to be deployed into the Open Registry. It matches the schema of the URN to identify what cryptographic standards are being used and adjusts the keys accordingly.

Parsing

For ECC keys, the SDK checks the first byte. If the first byte is 0x04 then it compresses the key to minimize amount of data stored. If the first byte is 0x02 or 0x03 then it's already compressed.

Compressing

Compression is done by eliminating Y coordinate from the public key, since elliptic curve is symmetric to X axis. Though information on which side of X the point is located is crucial. That's why polarity is appended to the x coordinate of compressed key. And since ECC uses modulo, one just need to know whether it's even or odd. To demonstrate consider values -1, 1 and modulo 5. Since -1 % 5 = 4 and 1 % 5 = 1 it's clearly distinguishable where value falls.

even --> 0x02
odd  --> 0x03

We've built our own library to compress and decompress public keys for secp256r1. It can be found at: https://github.com/chronicled/open-registry-utils

Specifically, the method is ec.compress(<Public key>); For our example, compressing will result in: 027462163f89fc02b989e564cf7a2ce39a806273ee4042201fb5544cc794c48975. Now public key is compressed and ready to be deployed as an identity of a Thing in the Open Registry.

RSA Public Key

URN format of an RSA public key is as follows:

pbk:rsa:<key size in bits>:<public key of defined size><exponent used>

A sample RSA public key in URN format with 2048 bits key and exponent 0x010001 is:

pbk:rsa:2048: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

Electronic Product Code

We're using same format described in the standard, though urn: prefix is omitted for brevity. Before EPC identity is getting stored in Open Registry ID portion of URN is encoded following standard description.

Useful Resources

Standards naming: https://www.ietf.org/rfc/rfc4492.txt EPC Tag Data Standard: http://www.gs1.org/sites/default/files/docs/epc/TDS_1_9_Standard.pdf

Copyright

Copyright (c) 2016 Chronicled, Inc. All rights reserved.