morphit/docs/adr/0033-decred-addition.md

ADR-0033: Decred (DCR) Addition — Trade-Only with Hybrid PoW/PoS Consensus and Opt-In CSPP Mixing

Status: Accepted (Part 122 cp43, 2026-05-19)

Context:

Following Pirate Chain (ADR-0032), Zcash (ADR-0031), Dogecoin (ADR-0030), Dash (ADR-0027), Litecoin (cp24), Bitcoin Cash (cp21), DAI (ADR-0029), USDC (ADR-0028), USDT (Part 121), and the founders' BLURT/BTC/XMR set, Morphit adds Decred (DCR) as the thirteenth tradable asset. Decred is a hybrid Proof-of-Work + Proof-of-Stake cryptocurrency launched in 2016. Every block is mined by PoW miners AND voted on by 5 PoS ticket-holders chosen pseudo-randomly from the staking pool — neither group can change protocol rules unilaterally. On-chain governance via Politeia lets stakeholders propose, debate, and ratify protocol changes; treasury funds (10% of block reward) flow through community vote.

The chain is transparent at the base layer (sender, recipient, and amount visible on chain like Bitcoin) but ships an opt-in CoinShuffle++ (CSPP) mixing protocol integrated into dcrwallet for users who want transaction-level privacy.

Decision

1. DCR is a Category-B trade-only asset

Per Memory #23 the fee_method enum stays frozen at {blurt, btc, xmr, waived_first_buy}. DCR therefore ships with canBeTraded: true and canPayListingFee: false, matching the BCH/LTC/DASH/DOGE/USDT/USDC/DAI/ZEC/ARRR pattern.

2. Single-network mainnet

Decred has a testnet but Morphit trades only on mainnet, consistent with every other single-network asset.

3. Address regex — two receive formats (Ds + Dc)

The canonical registry's addressShape regex accepts both Decred receive-address formats:

^D[sc][1-9A-HJ-NP-Za-km-z]{33}$

• Ds prefix: P2PKH-Secp256k1 (most common receive format)
• Dc prefix: P2SH (multisig / escrow scripts)
• 33 base58 data chars after the 2-char prefix = 35 chars total
• Base58 alphabet excludes 0, O, I, l (we use [1-9A-HJ-NP-Za-km-z])

Other Decred prefixes exist but are REJECTED by this regex:

• Dp extended pubkey — used for HD wallet derivation, not for receiving payments
• Dr extended privkey — SENSITIVE; never publish; rejecting it defends against a user accidentally pasting their xprv-equivalent into the trade form
• De Edwards-curve — Decred supports Edwards-curve addresses but they're rarely used and not the canonical receive format

4. NEW csppmix privacy tech tag

CoinShuffle++ (CSPP) is a wallet-side multi-party mixing protocol integrated into dcrwallet. Users enable the "Mix Account" option; deposits flow through CSPP rounds with other participants before becoming spendable from the mixed account. Mixing rounds happen approximately every 20 minutes on mainnet.

'csppmix' is added as a new value to the optInPrivacyTech type union, joining 'mweb' (LTC), 'cashfusion' (BCH), 'coinjoin' (BTC), 'payjoin' (BTC), 'privatesend' (DASH), and 'shielded-pools' (ZEC, ARRR). The cp42-J-68 LL #51 discipline was applied — the type union was widened BEFORE the DCR entry was added, avoiding the bug class where cp39 ZEC and cp41 ARRR both shipped with TypeScript compile errors.

Per LL #49 (cp40), the i18n keys privacy.opt_in_tech.csppmix.{name,explain} were added × 10 locales same-turn. The cp40 defensive smoke privacy-features-registry-smoke walks every registered tech tag dynamically, so DCR's csppmix tag is automatically covered.

5. Chat-link explorer default — dcrdata.decred.org

The operator surveyed 4 candidate explorers at addition time. The bundled default is dcrdata.decred.org — the official Decred project explorer, project-aligned, no third-party tracking, supports both transparent and mixed-output transactions, full Politeia governance integration.

Full survey:

Explorer	Disposition	Rationale
dcrdata.decred.org	Chosen	Official Decred project explorer; project-aligned
blockchain.com/explorer/assets/dcr	Available	Third-party aggregator; multi-asset
dcr.tokenview.io	Available	Tokenview multi-chain explorer
bitinfocharts.com/decred/	Available	Community analytics + block explorer

Operators wanting different defaults override via MORPHIT_FRONTEND_DCR_CHAT_LINK_URL.

6. Universal no-favoritism principle (adopted at cp39, reapplied at cp41 and cp43)

Decred ships chain-level transparency with opt-in wallet-side mixing. Per the universal no-favoritism principle adopted at cp39 (ADR-0031 §5) and reapplied at cp41 (ADR-0032 §6), Morphit's framing of DCR describes what the chain is (hybrid PoW/PoS consensus with on-chain governance via Politeia; opt-in CSPP wallet-side mixing for transaction-level privacy) WITHOUT comparative claims against XMR, ZEC, ARRR, DASH, BTC, or any other privacy-enabled chain. The phrase "the most private" does not appear in any DCR-related copy.

7. decred: URI scheme

The payment-URI builder emits decred:<address>?amount=<decimal> — BIP-21-style. Both receive-address formats (Ds P2PKH and Dc P2SH) are handled under the same scheme. Decred wallets (dcrwallet, Decrediton, Cake Wallet for DCR) recognize the decred: scheme.

8. Decimals = 8

DCR uses 8 decimals — same smallest-unit semantics as the BTC family. Decred inherited this from a Bitcoin-derived codebase. Amount-jitter routes through jitterUtxoAmount (same as BTC/BCH/LTC/DASH/DOGE/ZEC/ARRR).

9. Brand color text-teal-500

Distinct from all 12 existing accent classes. Decred's brand palette is teal-green (#2dd8a3) and blue (#2970ff); text-teal-500 lands the teal accent without collision. Verified at cp43 via the cp42 asset-accent-class-uniqueness-smoke.

Consequences

• DCR is enabled by default on every fresh Morphit instance. Operators preferring not to support DCR can disable via MORPHIT_INDEXER_DISABLED_ASSETS="DCR".
• The frozen fee_method enum is unaffected. Listing fees stay BLURT/BTC/XMR.
• Pre-launch operators who configured their instance before cp43 are unaffected by DCR addition; the indexer-client mirror declares dcr?: string | null as optional and the frontend's defensive-fallback uses the bundled dcrdata.decred.org default when the response field is missing.
• Users coming from the Decred community see their chain's framing as factual — no Morphit copy compares DCR's privacy posture against XMR, ZEC, ARRR, DASH, or BTC coinjoin.
• The new csppmix tech tag enriches the privacy framework. Future asset additions with wallet-side mixing protocols can either reuse csppmix (if they implement CoinShuffle++) or add a new tag — applying the cp42-J-68 LL #51 discipline (widen the type union BEFORE adding the entry that uses it).

References

• ADR-0026 (Transparent-chain privacy framework — established the privacyFeatures struct).
• ADR-0031 (Zcash addition — established the shielded-pools tech tag; adopted universal no-favoritism principle).
• ADR-0032 (Pirate Chain addition — reaffirmed universal no-favoritism principle; LL #50 same-format-different-chain).
• Decred protocol — https://docs.decred.org (project documentation)
• CoinShuffle++ paper — https://decred.org/research/ruffing2017-coinshuffle.pdf
• Memory #23 (fee_method enum frozen at BLURT/BTC/XMR).
• Memory #29 (NEW-asset i18n native-en/es/fr/de + EN-fallback for it/pl/ru/fa/zh-CN/zh-HK).
• Cp32 LL #36 (payment-rail axis same-turn discipline).
• Cp33 CODE-3 (atomically widen all 4 wire-format gates).
• Cp40 LL #49 (defensive smokes must verify i18n existence for dynamic-key reads — auto-covered DCR's csppmix tag).
• Cp42-J-68 LL #51 candidate (widen optInPrivacyTech type union BEFORE adding entries that use new tags — applied proactively at cp43, no TS compile error).