viper-pqchain 0.3.0

Python SDK for Viper PQ Chain — post-quantum trust infrastructure, aligned with the viper-pq-1 launch architecture (ADR-053). 0.3.0 adds typed read methods for the algorithm registry, single-validator detail, account attestation listing and on-chain governance proposals + votes.

viper-pqchain — Python SDK

Python SDK for Viper PQ Chain — post-quantum trust infrastructure.

Requires Python 3.9+. Zero external dependencies (uses only urllib from the standard library).

Installation

pip install viper-pqchain

Or from source:

cd sdk/python
pip install -e .

Quick start

from viper_pqchain import ViperClient

client = ViperClient("http://localhost:9000")

# Chain status
status = client.get_status()
print(f"Height: {status.height}  chain: {status.chain_id}")

# Fetch an account
account = client.get_account("01" * 32)
print(f"Balance: {account.balance} venom  nonce: {account.nonce}")

# Fetch a block
block = client.get_block(1)
print(f"Block 1 proposer: {block.header.proposer_address}")

# List validators
validators = client.get_validators()
for v in validators:
    print(f"  {v.address}  status={v.status}  stake={v.stake} venom")

Fee estimation

from viper_pqchain import ViperClient

client = ViperClient("http://localhost:9000")
calc = client.get_fee_calculator()

est = calc.estimate("vault_create", payload_bytes=256)
print(f"Estimated fee: {est.total_venom} venom")
print(f"  base:      {est.breakdown.base_fee_venom}")
print(f"  bytes:     {est.breakdown.byte_fee_venom}")
print(f"  sigverify: {est.breakdown.sigverify_fee_venom}")
print(f"  execution: {est.breakdown.execution_fee_venom}")

Building unsigned transactions

from viper_pqchain.tx import build_vault_create, build_vault_transfer, build_attestation_create
from viper_pqchain.types import VaultCreateParams, VaultTransferParams, AttestationCreateParams
import json

# Vault creation
tx = build_vault_create(
    VaultCreateParams(
        sender="01" * 32,
        nonce=0,
        alg_id="ml-dsa-65",
        public_key="<hex-encoded-ml-dsa-65-public-key>",
    ),
    fee_budget_venom=20_000,
)
print(json.dumps(tx, indent=2))

# Token transfer
tx = build_vault_transfer(
    VaultTransferParams(
        sender="01" * 32,
        nonce=1,
        recipient="02" * 32,
        amount_venom=10**18,  # 1 VPR
    ),
    fee_budget_venom=15_500,
)

# Attestation
tx = build_attestation_create(
    AttestationCreateParams(
        sender="01" * 32,
        nonce=2,
        subject="03" * 32,
        schema_id="aa" * 32,
        payload_hex="deadbeef",
    ),
    fee_budget_venom=18_512,
)

Signing workflow

ML-DSA (FIPS 204) has no mature Python implementation as of 2026. Signing must be performed externally:

# 1. Build the unsigned tx JSON (as above) and save it
python my_script.py > unsigned_tx.json

# 2. Sign with the pqcd CLI
pqcd sign-tx --tx-json unsigned_tx.json --key-file my_key.pem > signed_tx.hex

# 3. Submit

from viper_pqchain import ViperClient

client = ViperClient("http://localhost:9000")
cbor_hex = open("signed_tx.hex").read().strip()
result = client.submit_tx(cbor_hex)
print(result.status, result.tx_hash)

VPR / venom conversion

from viper_pqchain.utils import venom_to_vpr, vpr_to_venom

print(venom_to_vpr(10**18))          # "1.000000000000000000"
print(vpr_to_venom("1.5"))           # 1500000000000000000

Error handling

from viper_pqchain import ViperClient, ViperError

client = ViperClient("http://localhost:9000")
try:
    account = client.get_account("00" * 32)
except ViperError as e:
    print(e.status_code, e.code, str(e))

API reference

Method	Endpoint	Returns
get_status()	GET /v1/status	ChainStatus
get_block(height)	GET /v1/blocks/:height	Block
get_block_by_hash(hash)	GET /v1/blocks/:hash	Block
get_transaction(tx_hash)	GET /v1/txs/:hash	Transaction
submit_tx(cbor_hex)	POST /v1/txs	SubmitTxResponse
get_account(address)	GET /v1/accounts/:address	Account
get_attestation(id)	GET /v1/attestations/:id	Attestation
get_account_attestations(address)	GET /v1/accounts/:address/attestations	list[Attestation]
get_validators()	GET /v1/validators	list[Validator]
get_validator(address)	GET /v1/validators/:address	Validator
get_governance_parameters()	GET /v1/governance/parameters	GovernanceParameters
get_fee_calculator()	fetches params, returns calculator	FeeCalculator

Running tests

cd sdk/python
python -m pytest tests/ -v

26 tests, 0 failures.