Sixty Nuts - A NIP-60 Cashu Wallet in Python

A lightweight, stateless Cashu wallet implementation following NIP-60 specification for Nostr-based wallet state management.

Features

• NIP-60 Compliant: Full implementation of the NIP-60 specification
• NIP-44 Encryption: Secure encryption using the NIP-44 v2 standard
• Stateless Design: Wallet state stored on Nostr relays
• Multi-Mint Support: Can work with multiple Cashu mints
• Async/Await: Modern Python async implementation
• LNURL Support: Send to Lightning Addresses and other LNURL formats

Installation

pip install sixty-nuts

Usage

Basic Setup

import asyncio
from sixty_nuts import Wallet

async def main():
    # Create wallet with private key (hex or nsec format)
    wallet = await Wallet.create(
        nsec="your_nostr_private_key_hex",  # or "nsec1..." bech32 format
        mint_urls=["https://mint.minibits.cash/Bitcoin"],
        relays=["wss://relay.damus.io", "wss://nostr.wine"]
    )
    
    # Or use context manager for automatic cleanup
    async with Wallet(
        nsec="your_nostr_private_key_hex",
        mint_urls=["https://mint.minibits.cash/Bitcoin"]
    ) as wallet:
        # Wallet operations here
        pass

asyncio.run(main())

Temporary Wallets (No NSEC Required)

If you need a wallet with ephemeral keys that are not stored anywhere, use TempWallet:

import asyncio
from sixty_nuts import TempWallet

async def main():
    # Create a temporary wallet with auto-generated keys
    # No NSEC required - keys are generated randomly
    async with TempWallet(
        mint_urls=["https://mint.minibits.cash/Bitcoin"],
        currency="sat"
    ) as wallet:
        # Use the wallet normally
        state = await wallet.fetch_wallet_state()
        print(f"Balance: {state.balance} sats")
        
        # The private key is not stored anywhere
        # When the wallet is closed, the keys are lost forever
    
    # Alternative creation methods:
    temp_wallet = TempWallet()  # Uses default mint
    
    # Or with async factory
    temp_wallet2 = await TempWallet.create(
        mint_urls=["https://mint.minibits.cash/Bitcoin"],
        auto_init=False  # Skip relay connections
    )
    
    await temp_wallet.aclose()
    await temp_wallet2.aclose()

asyncio.run(main())

Note: TempWallet is useful for:

• One-time operations where you don't need to persist the wallet
• Testing and development
• Privacy-focused applications where keys should be ephemeral
• Scenarios where you want to receive/send tokens without storing keys

Minting Tokens (Receiving via Lightning)

async def mint_tokens(wallet: Wallet):
    # Create a Lightning invoice for 1000 sats
    invoice, payment_confirmation = await wallet.mint_async(1000)
    
    print(f"Pay this Lightning invoice: {invoice}")
    print("Waiting for payment...")
    
    # Wait for payment (with 5 minute timeout)
    paid = await payment_confirmation
    
    if paid:
        print("Payment received! Tokens minted.")
        # Check wallet balance
        state = await wallet.fetch_wallet_state()
        print(f"New balance: {state.balance} sats")
    else:
        print("Payment timed out")

Sending Tokens

async def send_tokens(wallet: Wallet):
    # Send 100 sats as a Cashu token
    amount = 100
    
    # Check balance first
    state = await wallet.fetch_wallet_state()
    print(f"Current balance: {state.balance} sats")
    
    if state.balance >= amount:
        # Create a Cashu token
        token = await wallet.send(amount)
        print(f"Send this token to recipient: {token}")
        
        # Check new balance
        new_state = await wallet.fetch_wallet_state()
        print(f"New balance: {new_state.balance} sats")

Receiving Tokens

async def receive_tokens(wallet: Wallet):
    # Redeem a received Cashu token
    token = "cashuA..."  # Token received from someone
    
    try:
        await wallet.redeem(token)
        print("Token redeemed successfully!")
        
        # Check new balance
        state = await wallet.fetch_wallet_state()
        print(f"New balance: {state.balance} sats")
    except Exception as e:
        print(f"Failed to redeem token: {e}")

Paying Lightning Invoices (Melting)

async def pay_invoice(wallet: Wallet):
    # Pay a Lightning invoice using your tokens
    invoice = "lnbc..."  # Lightning invoice to pay
    
    try:
        await wallet.melt(invoice)
        print("Invoice paid successfully!")
        
        # Check remaining balance
        state = await wallet.fetch_wallet_state()
        print(f"Remaining balance: {state.balance} sats")
    except Exception as e:
        print(f"Payment failed: {e}")

Checking Wallet State

async def check_wallet(wallet: Wallet):
    # Fetch current wallet state from Nostr relays
    state = await wallet.fetch_wallet_state()
    
    print(f"Balance: {state.balance} sats")
    print(f"Number of proofs: {len(state.proofs)}")
    print(f"Connected mints: {list(state.mint_keysets.keys())}")
    
    # Show proof denominations
    denominations = {}
    for proof in state.proofs:
        amount = proof["amount"]
        denominations[amount] = denominations.get(amount, 0) + 1
    
    print("Denominations:")
    for amount, count in sorted(denominations.items()):
        print(f"  {amount} sat: {count} proof(s)")

Sending to Lightning Addresses (LNURL)

async def send_to_lightning_address(wallet: Wallet):
    # Send to a Lightning Address (user@domain.com format)
    lnurl = "satoshi@bitcoin.org"
    amount = 500  # sats
    
    try:
        paid_amount = await wallet.send_to_lnurl(lnurl, amount)
        print(f"Successfully sent {paid_amount} sats to {lnurl}")
    except Exception as e:
        print(f"Failed to send: {e}")
    
    # You can also send to other LNURL formats:
    # - Bech32 encoded: "LNURL1DP68GURN8GHJ7..."
    # - With prefix: "lightning:user@domain.com"
    # - Direct URL: "https://lnurl.service.com/pay/..."
    
    # Custom fee parameters
    await wallet.send_to_lnurl(
        lnurl,
        amount=1000,
        fee_estimate=0.02,  # 2% fee estimate
        max_fee=50,         # Maximum 50 sats fee
    )

Complete Example

import asyncio
from sixty_nuts import Wallet

async def example_wallet_operations():
    # Initialize wallet
    async with Wallet(
        nsec="your_nostr_private_key_hex",
        mint_urls=["https://mint.minibits.cash/Bitcoin"],
        currency="sat"
    ) as wallet:
        # Check initial balance
        state = await wallet.fetch_wallet_state()
        print(f"Initial balance: {state.balance} sats")
        
        # Mint some tokens
        if state.balance < 1000:
            invoice, task = await wallet.mint_async(1000)
            print(f"Pay invoice to add funds: {invoice}")
            paid = await task
            if paid:
                print("Funded!")
        
        # Send tokens
        if state.balance >= 100:
            token = await wallet.send(100)
            print(f"Token to share: {token}")
        
        # Send to Lightning Address
        if state.balance >= 500:
            await wallet.send_to_lnurl("user@ln.tips", 500)
            print("Sent to Lightning Address!")
        
        # Final balance
        final_state = await wallet.fetch_wallet_state()
        print(f"Final balance: {final_state.balance} sats")

if __name__ == "__main__":
    asyncio.run(example_wallet_operations())

Architecture

• wallet.py - Main wallet implementation
• crypto.py - Cryptographic primitives (BDHKE and NIP-44 v2 encryption)
• mint.py - Cashu mint API client
• relay.py - Nostr relay WebSocket client
• lnurl.py - LNURL protocol support for Lightning Address payments

TODO

Core Implementation

• Proof-to-Event-ID Mapping: Implement proper mapping between proofs and their containing event IDs (wallet.py:66)

  • Currently missing in WalletState dataclass
  • Required for accurate token event management and proper deletion when proofs are spent

• Quote Tracking (NIP-60): Implement quote tracking as per NIP-60 specification (wallet.py:776)

  • Need to publish kind 7374 events for mint quotes
  • Track quote expiration and status

• Minted Quote Tracking: Properly track minted quotes to avoid double-minting (wallet.py:806)

  • Maintain state of which quotes have been successfully minted
  • Check existing token events for quote IDs in tags

• Coin Selection Algorithm: Implement better coin selection algorithm (wallet.py:956)

  • Current implementation is naive (first-fit)
  • Should optimize for privacy and minimize number of proofs used

Security & Cryptography

• Implement proper BDHKE blinding for Cashu operations
• Improve proof tracking to correctly identify which proofs belong to which token events (wallet.py:1031)

Features (todo)

• Support for P2PK ecash (NIP-61)
• Add comprehensive test suite
• Implement wallet recovery from relay state
• Add multi-mint transaction support

License

MIT