ZeroChain SDK — Python Client for the Zus Blockchain

Overview​

ZeroChain SDK (zerochain) is a Python client library for the Zus blockchain network (formerly 0Chain). It provides a complete interface for interacting with a decentralized storage blockchain — from wallet management and token transfers to file upload/download with erasure-coded sharding across multiple storage nodes (blobbers).

The SDK follows the design of the official Go-based ZBox/ZClient CLI tools but reimplements every operation in Python. Because the Zus blockchain uses BN254 BLS signatures — a curve not well-supported in native Python — the SDK bridges to a small Node.js sidecar (bls-wasm) via subprocess for cryptographic signing.

Key Features​

• Wallet management: Create and restore wallets, get token balances, receive faucet tokens, send transactions
• Storage allocations: Full CRUD for storage allocations — create, list, get info, cancel, and manage read/write pools
• File operations: Upload files with Reed-Solomon erasure coding (4 data + 2 parity shards) distributed across blobber nodes; download and reassemble files from shards
• Blobber discovery: Query blobber info, stats, and availability; stake/unstake tokens with blobbers
• Staking operations: Miner/sharder staking, delegation, and settings management
• Vesting pools: Create and manage token vesting pools
• Consensus engine: HTTP requests are fanned out to all miners/sharders in parallel via ThreadPoolExecutor; a simple counting algorithm determines consensus from the highest number of matching responses
• Transaction lifecycle: Build, sign (BLS), submit to miners, then poll sharders for confirmation status

Architecture​

A layered SDK with a JavaScript cryptographic bridge:

┌──────────────────────────────────────────┐
│          Actions Layer (zerochain/actions/)│
│  wallet / allocation / blobber / interest  │
│  miner / vesting / network                 │
└──────────────┬───────────────────────────┘
               │ delegates to
┌──────────────▼───────────────────────────┐
│         Client (client.py)               │
│  ConnectionBase ── consensus HTTP engine  │
│  Transaction ───── build/sign/submit/check│
│  Network ────────── miner/sharder discovery│
└──────────────┬───────────────────────────┘
               │ signs via
┌──────────────▼───────────────────────────┐
│     JS Bridge (lib/bn254_js/)            │
│  sign.js ── bls-wasm (BN254 curve)       │
│  generate_keys.js ── bip39 + bls-wasm    │
└──────────────────────────────────────────┘

The consensus engine is the backbone: ConnectionBase._consensus_from_workers() fires parallel HTTP requests to all configured miners and sharders, then uses a simple counting algorithm to determine the canonical response.

Tech Stack​