PowerHash Abstract
PowerHash (PWDH) is an open-source, Proof-of-Work cryptocurrency designed to remain secure in a future where cryptographically relevant quantum computers exist. It combines the proven SHA-256d mining algorithm — compatible with existing ASIC hardware — with NIST-standardized post-quantum digital signatures: ML-DSA (CRYSTALS-Dilithium, FIPS 204), spendable through P2MR outputs (BIP 360, SegWit witness version 2). The codebase builds on the extensively reviewed Bitcoin Core 26.x, released under the MIT license. Blocks are produced every 60 seconds, difficulty retargets every block using LWMA, and the monetary supply is capped at 21,000,000 PWDH with a halving every 2,100,000 blocks. There is no premine; PowerHash is a fair launch by a community that has been together since 1998.
The ticker PWDH reads as Proof-of-Work Double Hash: a reference to the SHA-256d (double SHA-256) construction that miners compute — the same battle-tested hash function as Bitcoin, which is why existing SHA-256 ASIC hardware can mine PowerHash out of the box. While signatures move to post-quantum ML-DSA, the proof-of-work itself remains secure against quantum attacks: Grover's algorithm yields only a quadratic speedup against hashing, leaving an ample security margin at 256 bits.
1. Introduction
Virtually all deployed cryptocurrencies derive ownership from elliptic-curve digital signatures — ECDSA or Schnorr over secp256k1. The security of these schemes rests on the hardness of the elliptic-curve discrete logarithm problem, which is known to be efficiently solvable by a sufficiently large fault-tolerant quantum computer running Shor's algorithm. While such machines do not exist today, the long-lived nature of blockchain records makes the threat concrete: any coin whose public key has been exposed on-chain becomes vulnerable the moment a cryptographically relevant quantum computer is available.
PowerHash addresses this at the protocol level rather than as an afterthought. It integrates a NIST-standardized, lattice-based signature scheme — ML-DSA — as a first-class output type, while deliberately keeping everything else conservative: the Bitcoin Core consensus engine, SHA-256d Proof-of-Work, and a fixed, transparent emission schedule.
The project is stewarded by a community that has existed since 1998 — a fact permanently recorded in the genesis block message: “PWDH Community forever since 1998”.
2. Design Goals
- Quantum resilience where it matters. Transaction authorization — the signature layer — must survive Shor's algorithm. Hash-based components of the protocol are retained where they remain secure (see §4).
- Conservative consensus. Reuse the extensively reviewed Bitcoin Core 26.x consensus and networking stack instead of inventing a new one.
- Hardware compatibility. Mining must remain possible with existing SHA-256 ASICs; no trusted hardware and no novel mining algorithm.
- Fair distribution. No premine, no founder reward, no ICO. Coins enter circulation exclusively through Proof-of-Work.
- Backwards choice. Classic address types (legacy, P2SH-SegWit, bech32, bech32m/Taproot) remain available; post-quantum P2MR is opt-in at the protocol level and the default in the reference wallet.
- Openness. All code is open source under the MIT license.
3. Consensus & Mining
3.1 Proof-of-Work: SHA-256d
PowerHash uses double SHA-256 (SHA-256d) as its Proof-of-Work function, identical to Bitcoin's. This is a deliberate engineering decision: the algorithm has been subjected to over a decade of public cryptanalysis, and a mature, competitive ASIC ecosystem already exists. Any miner capable of SHA-256d can secure the PowerHash network without new hardware.
3.2 Block interval and difficulty adjustment
The target block interval is 60 seconds. Difficulty is retargeted every block using a Linear Weighted Moving Average (LWMA) algorithm, which responds quickly to hashrate fluctuations and limits the profitability of timestamp manipulation and coin-hopping strategies that slower retarget windows permit.
3.3 Emission schedule
The initial block subsidy is 5 PWDH, halving every 2,100,000 blocks — approximately four years at the 60-second target. The geometric series converges to a hard maximum supply of 21,000,000 PWDH, with the tail of the emission extending over roughly 131 years.
| Era | Block range | Reward (PWDH) | Era emission (PWDH) | Cumulative supply |
|---|---|---|---|---|
| 0 | 0 – 2,099,999 | 5 | 10,500,000 | 10,500,000 |
| 1 | 2,100,000 – 4,199,999 | 2.5 | 5,250,000 | 15,750,000 |
| 2 | 4,200,000 – 6,299,999 | 1.25 | 2,625,000 | 18,375,000 |
| 3 | 6,300,000 – 8,399,999 | 0.625 | 1,312,500 | 19,687,500 |
| 4 | 8,400,000 – 10,499,999 | 0.3125 | 656,250 | 20,343,750 |
| 5 | 10,500,000 – 12,599,999 | 0.15625 | 328,125 | 20,671,875 |
| 6 | 12,600,000 – 14,699,999 | 0.078125 | 164,062.5 | 20,835,937.5 |
| 7 | 14,700,000 – 16,799,999 | 0.0390625 | 82,031.25 | 20,917,968.75 |
| 8 | 16,800,000 – 18,899,999 | 0.01953125 | 41,015.625 | 20,958,984.375 |
| 9 | 18,900,000 – 20,999,999 | 0.009765625 | 20,507.8125 | 20,979,492.1875 |
| 10 | 21,000,000 – 23,099,999 | 0.0048828125 | 10,253.90625 | 20,989,746.09375 |
| … | … | halving continues | … | → 21,000,000 (asymptotic) |
SegWit, Taproot, CSV (BIP 112) and CLTV (BIP 65) are active from the genesis block; the full modern Bitcoin script toolbox is available from day one.
4. Post-Quantum Cryptography
4.1 ML-DSA-65 (FIPS 204)
PowerHash's quantum-safe signature scheme is ML-DSA-65, the module-lattice-based digital signature algorithm standardized by NIST in FIPS 204 (derived from CRYSTALS-Dilithium). PowerHash uses the ML-DSA-65 parameter set (NIST security category 3, ~192-bit security) — deliberately one level above the ML-DSA-44 set used by comparable projects — because the chain is designed for decades of service. Its security relies on the hardness of lattice problems (Module-LWE / Module-SIS), for which no efficient quantum algorithm is known — in contrast to the number-theoretic assumptions behind ECDSA and Schnorr signatures. Keys: 1952-byte public keys, 3309-byte signatures.
4.2 P2MR outputs (BIP 360)
ML-DSA keys and signatures are too large for legacy script templates, so PowerHash
implements Pay-to-Merkle-Root (P2MR) as specified by
BIP 360: a new SegWit output type at witness version
2. P2MR commits to a Merkle root of the spending conditions, allowing
post-quantum signature scripts to live in the witness tree while keeping the on-chain
output compact. P2MR addresses are encoded with bech32m and are
recognizable by their pwdh1z… prefix.
4.3 What stays secure, and why
A common misconception is that quantum computers “break all of Bitcoin's cryptography.” They do not. Shor's algorithm breaks discrete-logarithm- and factoring-based schemes (ECDSA, Schnorr, RSA). Hash functions such as SHA-256 are affected only by Grover's algorithm, which provides at most a quadratic speedup — effectively halving the security level. SHA-256 at a 256-bit output therefore retains ~128 bits of post-quantum security, which remains comfortably out of reach. Consequently:
- Proof-of-Work (SHA-256d) remains secure; Grover's quadratic speedup does not break mining economics or difficulty, it merely scales them.
- Address hashing and Merkle trees remain secure for the same reason.
- The vulnerable component is authorization — the signature layer. This is exactly the layer PowerHash replaces with ML-DSA via P2MR.
Practical guidance: funds held in quantum-safe P2MR
(pwdh1z…) outputs are protected against Shor-based key recovery. Classic
address types remain fully functional for convenience and compatibility, but users
seeking long-term, quantum-resilient storage should prefer P2MR.
4.4 Address formats
| Type | Signature scheme | Encoding | Quantum-safe |
|---|---|---|---|
| P2MR (witness v2) | ML-DSA (FIPS 204) | bech32m, pwdh1z… | Yes |
| Taproot (P2TR) | Schnorr | bech32m | No |
| Native SegWit (P2WPKH/P2WSH) | ECDSA | bech32 | No |
| P2SH-SegWit | ECDSA | Base58Check | No |
| Legacy (P2PKH) | ECDSA | Base58Check | No |
5. Block Capacity & Fees
Post-quantum signatures are large: an ML-DSA-65 signature plus public key accounts for
roughly 5.3 KB per spent input, an order of magnitude more than a
compact ECDSA signature. To keep transaction throughput high regardless, PowerHash
raises the block weight limit to 16 MWU (16 MB serialized)
with a WITNESS_SCALE_FACTOR of 16 (compared to Bitcoin's 4 MWU /
factor 4). With 60-second blocks this yields a capacity of roughly
2,600 quantum-safe inputs per block — several thousand transactions
per minute — and considerably more for classical transaction types.
The higher scale factor also rebalances the economics of witness data: because post-quantum signature material resides in the witness, the adjusted accounting keeps the fee market functional while acknowledging the intrinsically larger witnesses of P2MR spends. Fees follow the familiar Bitcoin model — a market-based fee rate per unit of block weight, paid to miners.
6. Network Parameters
| Parameter | Mainnet | Testnet |
|---|---|---|
| P2P port | 1998 | 11998 |
| RPC port | 1999 | 11999 |
| Status | In preparation | Live |
Initial peer discovery on mainnet is bootstrapped via the DNS seed
seed.powerhash.org. Project infrastructure is reachable at
powerhash.org and powerhash.space.
7. Wallet & Usage
The reference software follows the Bitcoin Core tool layout:
powerhashd (daemon), powerhash-cli (RPC client) and
powerhash-qt, a graphical wallet for Windows and Linux. In the Qt
wallet, P2MR is the default address type in the receive dialog, presented through the
Vault Manager.
7.1 Creating quantum-safe addresses
# New P2MR (ML-DSA) receiving address
powerhash-cli getnewaddress "" "p2mr"
# Equivalent convenience RPC
powerhash-cli getnewdilithiumaddress7.2 Spending from P2MR outputs
Because ML-DSA signing differs from the legacy signature flow, P2MR spends are signed with a dedicated RPC:
# Build a transaction spending P2MR inputs, then sign it
powerhash-cli signp2mrtransaction '<unsigned-tx-hex>'7.3 Node configuration
# powerhash.conf — minimal mainnet example
server=1
listen=1
port=1998
rpcport=1999
rpcuser=<your-user>
rpcpassword=<strong-password>
addnode=seed.powerhash.org8. Roadmap
- Testnet launch — done. The public testnet is live with full P2MR / ML-DSA support.
- Mainnet launch — in preparation. Final consensus and wallet review ahead of the fair launch.
- Block explorer — planned. Public chain explorer and network statistics.
- Additional post-quantum schemes — planned. Evaluation and integration of further NIST-standardized signatures, including SLH-DSA (FIPS 205), to provide cryptographic agility and diversity of assumptions.
9. License & Risks
PowerHash is free and open-source software released under the MIT License. The codebase derives from Bitcoin Core and inherits their licensing terms.
Development status. PowerHash is currently in the testnet stage. Parameters, interfaces and consensus details described in this document reflect the testnet implementation and may be refined before mainnet launch. Nothing herein is a guarantee of future behavior.
No financial advice. This document describes a technical system for informational purposes only. It is not an offer, solicitation or recommendation to buy, sell or hold any asset, and it makes no representation about the present or future value of PWDH. Cryptocurrency systems involve risk, including the total loss of funds; run the software and transact at your own risk.
Cryptographic assumptions. ML-DSA is believed to resist known quantum attacks and is standardized by NIST, but — like all cryptography — its security rests on mathematical assumptions that ongoing research continues to scrutinize. The roadmap's cryptographic-agility work (e.g. SLH-DSA) exists partly to mitigate this residual risk.