Algo Models

Motivation

This package is meant for integrators that want to add Algorand's functionality to their applications.

Goal

• Interoperability with KMS systems
• Simple encoding / decoding of raw transactions, keys and addresses
• Builder pattern for crafting

For whom is this package?

• For the heavy user's or advanced integrators that want or need to work with interoperability between systems. Such as, cold vault system, HSM's, validation of encoded transaction payloads (i.e verification, attached signatures, API validations).

• For someone that wants to keep dependencies to a minimum rather than importing packages that bring everything into their toolchains.

• For anyone that wants to understand and learn about the format of the encoded transactions, how to validate and sign them.

Functionality

• Definition and crafting of models for Algorand's transactions that are compliant directly with the protocol and with algod's submission API.
  • algosdk, goal and Developer Portal work with models that are specific to eachother and other toolkits, but not directly with the protocol.
• Schemas for validation of encoded payloads against the protocol's expected transaction format and types.
  • Some differences from the SDK/ GOAL include:
    • snd / rcv are not a string representing the address but the corresponding public key / (x,y) point in compressed form (only 32 bytes required).
    • The encoded object doesn't include the txn field, only it's parameters.
    • gh is not a base64 string but the decoded bytes of the genesis hash. 32 bytes in size.

Install

$ yarn add @algorandfoundation/algo-models
Copy

or

$ git clone git@github.com:algorandfoundation/algo-models 
Copy

Tests

$ yarn install
$ yarn build
$ yarn test:cov
Copy

Craft Transaction

let { AlgorandTransactionCrafter, PayTransaction } = require('@algorandfoundation/algo-models')

// sample vars
const genId = "testnet-v1.0"
const genesisHash = "SGO1GKSzyE7IEPItTxCByw9x8FmnrCDexi9/cOUJOiI="
const amount = 1000000
const from = "TIQ4WPFJQYSP2SKLSCDWTK2IIQQ6FOS6BHYIYDGRUZSSROJC5P3HBCZ67Y"
const to = "66LKPOMVQJL2YVMTAVULQVZMZZCD5M2YVWA7KRHEOHYOJU5KLH2PB7HRRY"

const algoCrafter = new AlgorandTransactionCrafter(genId, genesisHash)

const tx: PayTransaction = algoCrafter
    .pay(amount, from, to)
    .addFirstValidRound(1000)
    .addLastValidRound(1500)
    .get()

// The encoding algorithm is a fork of the actual msgpack (https://github.com/EvanJRichard/msgpack-javascript)
// After msgpack encoding a TX TAG is added as a prefix to the result. 
const encoded: Uint8Array = tx.encode() // encoded msg ready - to be signed with EdDSA

Copy

Crafter + Signer

Suggested integration with external KMS's, HSM's and other Cold Vault Systems

    C4Context
        title Encoder & Signer
        Boundary(b0, "Application", $offsetX="0") {
            System(s0, "Crafter & Encoder", "System that crafts, encodes 
 and parepares transactions to be signed. 
 Delegates signing to a dedicated and ISOLATED KMS")
        }

        Boundary(b1, "KMS Environment", $offsetX="0") {
            System(s1, "KMS", " 
- HSM 
 - Cold Vault 
 - Hashicorp Vault 
 - Libsodium 
 - Tweetnacl")
            
        }

        BiRel(s0, s1, "Submit Encoded", "PKCS#11, REST, etc")

        UpdateRelStyle(s0, s1, $textColor="green", $lineColor="blue", $offsetX="-50")
        UpdateLayoutConfig($c4ShapeInRow="1", $c4BoundaryInRow="2")

Copy

Validate Encoded Payloads against protocol schema

Any system that receives or builds encoded payloads should validate them against the protocol's valid transaction schemas. These can be found in the schemas folder.

import fs from 'fs'
import Ajv, {JSONSchemaType} from "ajv"

// ...
const encoded: Uint8Array = tx.encode()

const ajv = new Ajv()

// get schemas/pay.transaction.json
const paySchema: JSONSchemaType<PayTransaction> = JSON.parse(fs.readFileSync(path.resolve(__dirname, "./schemas/pay.transaction.json"), "utf8"))

const validate = ajv.compile(paySchema)
expect(validate(tx)).toBe(true)

Copy

Attaching signatures

const ready: Uint8Array = algoCrafter.addSignature(encoded, signature) // ready to submit

// It can be decoded with: new AlgorandTransactionDecoder().decodeSignedTransaction(ready)

// optional: write to file with fs
import fs from 'fs'
fs.writeFileSync("/tmp/path/to/ready-tx-binary", ready)
Copy

Push transaction

curl --request POST -i -H "X-Algo-API-Token: ``" -H "Content-Type: application/x-binary" --data-binary "@/tmp/path/to/ready-tx-binary" https://testnet-api.algonode.cloud:443/v2/transactions

Copy

Schemas for models

Available in schemas folder