Sirius Chain Developer Center 0.2.6

Sirius Chain Developer Center 0.2.6

  • Getting Started
  • Built-in Features
  • REST API Endpoints
  • Guides
  • Cheat Sheet

›Built-in Features

Getting Started

  • What is ProximaX Sirius Chain
  • Setting up your workstation
  • Writing your first application

Built-in Features

  • Account
  • Mosaic
  • Namespace
  • Transfer Transaction
  • Aggregate Transaction
  • Multisig Account
  • Metadata
  • Account Restriction
  • Cross-Chain Swaps
  • Super Contracts

Protocol

  • Node
  • Block
  • Cryptography
  • Transaction
  • Validating
  • Consensus Algorithms
  • Receipt
  • Inflation

REST API

  • Overview
  • Tools
  • Serialization
  • Websockets
  • Status Errors

SDKs

  • Overview
  • Architecture
  • Languages
  • Extending Sirius Chain Capabilities
  • SDK Development
  • SDK Documentation

Client

  • Overview
  • Commands

Wallets & Explorers

  • Wallets & Explorers

Extensions

  • Overview
  • Sirius-Storage DFMS version extension

Cheat Sheet

  • Sirius Chain Cheat Sheet

Metadata

Sirius Chain provides you with an option to associate metadata to an account, mosaic or namespace with a transaction.

The most common uses of metadata are:

  • Attach relevant information to your assets.
  • Validate the value attached to an asset to enable users in your application to perform an off-chain action.

Metadata is uniquely identified by the tuple { signer, target-id, metadata-key }. Including a signer in this composite identifier allows multiple accounts to specify the same metadata without conflict.

The value linked to an identifier is a string up to 1024 characters. The client application is responsible for encrypting the message or keeping it visible for every blockchain participant.

Persistence¶

Metadata entries are stored in the blockchain—like the message of a regular TransferTransaction — but also as a key-value state.

This feature reduces the reading time of client applications; metadata allows information to be accessed by keys instead of processing the entire account transaction history off-chain to obtain the latest transaction message value.

Permissions

The account, namespace or mosaic owner must opt-in to all metadata requests received by giving explicit permission. In practice, this means that all MetadataTransactions must be wrapped in an AggregateTransaction.

The target account should cosign the aggregate to record the metadata on the blockchain and update the asset state.

Examples

Adding a certificate to an account

Metadata used to attach relevant information to an asset

Metadata used to attach relevant information to an asset

Bob works as a digital notary that stamp accounts on the Sirius Chain. When a customer comes to Bob to notarize a document, he checks the authentication of the customer’s documents then tags the account with a MetadataTransaction.

Alice a recent graduate and wants her educational certificate accredited to her Sirius Chain account to avoid the hassle of repeatedly providing verification of her degree. So she goes to Bob and provides him with proof of her degree. Once Alice pays Bob a fee, Bob verifies the authenticity and stamps Alice’s account with metadata that signifies her degree.

Access management

Validating metadata to restrict performing an off-chain action

Validating metadata to restrict performing an off-chain action

The HR department of the SneakersCompany uses the Sirius Chain for access management of sensitive work resources. Each account is tagged with the metadata that regulates its access to the company apps suite.

When a new employee, Carol, is hired, the HR department creates a new work account for her. For security reasons, HR sets the metadata of the account to {company, ACCESS, 9-18}.

Each time Carol attempts to access the company apps suite, the company app validates that Carol has permission and that the time falls under 9:00-18:00 before granting her admission.

On the other hand, if Derek, who has no permissions, attempts to access the company apps suite, the company app will reject his request.

Type of Metadata

Address

Since Address usually represents entities from the real world, it can be useful to attach some extra information to the address.

Guides on account metadata

Mosaic

For Mosaic, metadata could be used to share where users can obtain or exchange an asset.

Guides on mosaic metadata

Namespace

If users own a namespace, they can attach extra details with metadata for their own namespace.

Guides on namespace metadata

Schemas

ModifyMetadataTransaction

Announce an modify metadata transaction to associate a key-value state to an account, mosaic or namespace.

Version: 0x01

Entity typeDescription
0x413DModify account metadata
0x423DModify mosaic metadata
0x433DModify namespace metadata

Inlines:

  • Transaction or EmbeddedTransaction
PropertyTypeDescription
metadataTypeuint8 MetadataTypeType of the metadata to be associated.
metadataIdarray(bytes)It can be plain address, mosaicId in hex and namespaceId in hex. Depend on the metadataType.
modificationsarray(MetadataModification)Array of metadata modifications.

MetadataType

IdType
0x00None
0x01Address
0x02Mosaic
0x03Namespace

MetadataModification

PropertyTypeDescription
modificationSizeuint32 (4 bytes)The total size of the modification.
typeMetadataModificationTypeType of the metadata modification.
keySizeuint8The size of the key
valueSizeuint16The size of the value
keyarray(bytes)Key of the metadata.
valuearray(bytes)Value to be associate to the key.

MetadataModificationType

IdTypeDescription
0x00uint8Add
0x01uint8Remove
← Multisig AccountAccount Restriction →
  • Examples
    • Adding a certificate to an account
    • Access management
  • Type of Metadata
    • Address
    • Mosaic
    • Namespace
  • Schemas
    • ModifyMetadataTransaction
    • MetadataType
    • MetadataModification
    • MetadataModificationType
  • Join #general discussion
  • Ask development questions
  • Follow the dev updates
  • Explore Github
Protocol
BlockConsensus AlgorithmsCryptographyInflationNodeReceiptTransactionValidating
Built-in Features
AccountAccount FilterAggregate TransactionCross-Chain SwapsMetadataMosaicMultisig AccountNamespaceSuper contractTransfer Transaction
References
REST APISDKsXPX-Chain-CLICheat Sheet
Documentation Forked From NEM
Copyright © 2019 ProximaX