Why Tidecoin?

Tidecoin exists because the cryptocurrency migration problem is bigger than “swap ECDSA for a new signature algorithm.” Blockchains are public, permanent, high-value systems. If a chain exposes classical public keys for years and only migrates after quantum computers become urgent, old exposure remains part of the ledger forever.

Tidecoin takes the opposite path: post-quantum signatures from genesis, a Bitcoin-like UTXO architecture, and height-gated upgrade paths for broader post-quantum features.

This page is the high-level case for Tidecoin. It is not the whitepaper or a normative protocol reference; see Whitepaper and Protocol for full details.

The Core Argument

Nearly every major cryptocurrency still depends on ECDSA or Schnorr signatures. Those signatures are secure against known classical attacks, but Shor’s algorithm breaks their underlying discrete-log problem on a sufficiently large fault-tolerant quantum computer.

The usual answer is migration. Migration is necessary, but it has hard limits:

old public keys already revealed on-chain stay revealed;
lost or inactive funds may never move;
new signatures are larger and need fee/block-space planning;
every wallet, exchange, custodian, explorer, and signer must update;
consensus activation has to happen without splitting the network.

Tidecoin’s premise is that a chain intended for the quantum era should not spend its first decade accumulating classical-key exposure.

What Tidecoin Proves

Tidecoin demonstrates that a Bitcoin-style chain can run with post-quantum transaction signatures from block zero. Falcon-512 has secured mainnet spends since December 27, 2020. The chain preserves the familiar UTXO and node model while replacing the cryptographic assumptions that quantum computers directly break.

That matters because it turns post-quantum cryptocurrency from an abstract proposal into an operating network with real wallet, transaction, block, and node behavior.

Full-Stack Post-Quantum Design

Tidecoin’s post-quantum design covers more than signatures:

Area	Tidecoin position
Transaction signing	Falcon-512 live from genesis; Falcon-1024 and ML-DSA implemented behind activation rules.
Wallet derivation	PQHD replaces BIP32/xpub assumptions with hardened-only derivation.
Script hashing	Witness v1 SHA-512 support after AuxPoW activation.
P2P transport	ML-KEM-512 based post-quantum encrypted transport support.
Mining lifecycle	YespowerTIDE for pre-AuxPoW distribution, scrypt merged mining with Litecoin after AuxPoW.
Upgrade model	Conservative height-gated activation for major consensus changes.

This is what “full-stack PQ” means in the Tidecoin docs: the transaction lifecycle is designed around post-quantum constraints, not just the final signature check.

Why Keep Bitcoin Architecture

Tidecoin does not try to reinvent every part of a cryptocurrency system. It keeps the Bitcoin-style UTXO model, script validation approach, peer-to-peer node design, mempool/block validation flow, and operational expectations because those parts are well understood.

The engineering choice is narrow but deep: keep the battle-tested architecture, replace the cryptography that quantum computers break, and add the wallet and consensus machinery required to operate those new primitives safely.

Why Not Only Retrofit Bitcoin?

Bitcoin and other mature chains may eventually add post-quantum options. That work is important. It is also constrained by history:

old outputs may expose public keys directly;
reused addresses have already revealed keys;
user migration can take years;
larger signatures affect throughput and fees;
lost coins cannot sign a migration transaction.

Tidecoin is complementary to retrofit work. It shows what the design looks like when the post-quantum decision is made at genesis instead of at emergency migration time.

Why Merged Mining

Tidecoin’s mining model has two phases. YespowerTIDE supports pre-AuxPoW standalone mining and distribution. The planned long-term model is scrypt merged mining with Litecoin through AuxPoW, so Tidecoin can anchor its PoW security to a large existing scrypt mining base while giving miners an additional revenue stream.

Mining instructions and activation details belong in Mining and Activation Status. This page explains why the design exists.

The Practical Claim

Tidecoin is for people who want a Bitcoin-architecture proof-of-work chain whose transaction authorization has been post-quantum from the beginning. It is not a claim that quantum computers are breaking wallets today. It is a claim that ledger history is permanent, migrations are slow, and post-quantum design is better done before exposure accumulates.