Decred

driver

decred

curve

secp256k1

address formats

legacy ECDSA P2PKH

SLIP-44 coin

42'

Load it

import { useBlockchain, blockchains } from "@agntn/keys";

const decredChain = useBlockchain(await blockchains.decred()());
const testnet = useBlockchain(await blockchains.decred({ network: "testnet" })());

Mainnet and testnet3 only, anything else throws in the constructor.

The address

Decred looks like Bitcoin from a distance and swaps the hash the moment you get close. RIPEMD160(BLAKE256(pubkey)), a two byte prefix in front, then base58check with a double BLAKE-256 checksum instead of double SHA-256.

const privateKey = "0000000000000000000000000000000000000000000000000000000000000001";
const publicKey = decredChain.getKeyPublic(privateKey);

decredChain.getAddress(publicKey); // DsmcYVbP1Nmag2H4AS17UTvmWXmGeA7nLDx
testnet.getAddress(publicKey); // TsmfmUitQApgnNxQypdGd2x36djCCpDpERU

That's the only format. Ask for "segwit" or anything else and getAddress throws a RangeError instead of quietly handing you a legacy address. Schnorr and Ed25519 keys, which dcrd also knows, aren't implemented.

Validation

decredChain.validateAddress("DsmcYVbP1Nmag2H4AS17UTvmWXmGeA7nLDx"); // true
decredChain.validateAddress("TsmfmUitQApgnNxQypdGd2x36djCCpDpERU"); // false, testnet on a mainnet driver

Base58 decode with the BLAKE-256 checksum, 22 bytes of payload, and both prefix bytes have to match the driver's network. A Bitcoin address fails at the checksum before the prefix even gets a look.

Mnemonics

deriveHDWallet throws. dcrd's HD derivation strips leading zero bytes from keys where BIP32 keeps them, so a plain BIP32 walk lands on the wrong key for some paths and looks perfectly fine doing it. A driver that's silently wrong is worse than one that refuses, so it refuses. deriveWallet with a private key works as usual, and so does WIF:

import { encodeWIF, decodeWIF } from "@agntn/keys";

encodeWIF(privateKey, { chain: "decred" }); // PmQdGRXNZdAgEqwDZMLAF2XSQRLFeSFKi4HLPbdW3kC66HegjYtxq
decodeWIF(wif, { chain: "decred" }).privateKey;

Decred WIF has its own layout: two prefix bytes, a scheme byte that's 0x00 for ECDSA, the key, and a single BLAKE-256 checksum. Only the compressed form exists, compressed: false throws.

Signing

"Decred Signed Message:\n" with compact size lengths in front of the preamble and the message, one round of BLAKE-256, then secp256k1. 64 bytes of r||s in hex, verified with verifyMessage on the same driver.

Where it lives

src/blockchains/decred.ts, all of it. It extends AbstractBlockchain directly, not the Bitcoin base, because nothing except the curve is shared.