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Glossary

Curated glossary of terms used throughout the library. Where a term has a Bitcoin Gold (BTG)-specific meaning, that's noted.

A

Address (Bitcoin Gold (BTG)) A string that uniquely identifies a recipient of a transaction. Three formats are valid on Bitcoin Gold (BTG) mainnet:

  • G... — P2PKH (legacy, base58, version byte 0x26 / 38)
  • A... — P2SH (legacy, base58, version byte 0x17 / 23)
  • btg1... — Bech32 (native segwit, HRP btg)

API The set of commands a daemon accepts. For Bitcoin Gold (BTG) this is JSON-RPC over HTTP (port 8332, localhost only).

AuxPoW Auxiliary Proof of Work. Not used by Bitcoin Gold (BTG). Mentioned here because many older Bitcoin-fork docs reference it. Bitcoin Gold (BTG) uses pure Equihash-Bitcoin Gold (BTG) since block 491 407.

B

Bech32 Address format defined in BIP173. For Bitcoin Gold (BTG), the Human-Readable Part (HRP) is btg for mainnet and tbtg for testnet.

BIP Bitcoin Improvement Proposal. Bitcoin Gold (BTG) adopts most of the BIPs that don't require a Bitcoin-specific chain configuration (BIP44/49/84 use coin type 156).

BIP44 / BIP49 / BIP84 HD wallet derivation path standards. Bitcoin Gold (BTG) uses coin type 156 (hex 0x8000009c).

Block header The 80+ byte prefix of each block. Bitcoin Gold (BTG)'s header is Zcash-compatible and includes nHeight and nSolution (the Equihash solution).

Bootstrap Syncing the chain from a bootstrap.dat file instead of from peers. Faster on a fresh node, but the file must come from a trusted source. Bitcoin Gold (BTG) dropped the -bootstrap flag in v0.15.0.2.

Blockbook A Trezor-developed indexer that builds an address index on top of a Bitcoin-family full node, exposing a JSON REST API. The BTCGPU fork adds Bitcoin Gold (BTG)-specific address format constants.

C

Chainstate The in-memory and on-disk summary of all unspent transaction outputs (UTXOs). Required to validate new blocks without re-scanning the entire chain.

Compact block A compressed block representation that reduces bandwidth. Defined in BIP152. Bitcoin Gold (BTG) enabled compact blocks in v0.17.1.

CompactSize The Bitcoin-family variable-length integer encoding for byte lengths. Bitcoin Gold (BTG) inherits it unchanged.

Compaction RocksDB's background process that merges SST files. Visible in Blockbook logs as "compaction finished".

Consensus rules The set of rules a full node enforces. For Bitcoin Gold (BTG): Equihash-Bitcoin Gold (BTG) (N=144, K=5, personalization BgoldPoW), LWMA DAA, SIGHASH_FORKID = 79, two post-fork headers format.

CPU mining Not viable for Equihash-Bitcoin Gold (BTG) (N=144, K=5). 2.5 GB of RAM per thread. GPUs and a few specialized FPGA implementations are the practical mining hardware.

D

DAA (Difficulty Adjustment Algorithm) The rule that adjusts the mining target. Bitcoin Gold (BTG) uses Zawy's LWMA with a 45-block window since the July 2018 hardfork at height 536 200.

daemon The headless server component of a Bitcoin-family node. For Bitcoin Gold (BTG): bgoldd. Runs in the background and exposes JSON-RPC.

DAPPS Not applicable to Bitcoin Gold (BTG). Mentioned for completeness — Bitcoin Gold (BTG) does not have a smart-contract layer.

DNS seed A DNS server that returns a random set of full nodes when queried. New Bitcoin Gold (BTG) nodes query the seeds to bootstrap. As of 2026-06-06 the seeds that actually respond are dnsseed.bitcoingold.dev (mainnet), dnsseed.bitcoingold.services (mainnet, run by bitcoingold.services), and test-dnsseed.bitcoingold.dev (testnet). The hardcoded list in bgoldd's chainparams.cpp also includes several other hostnames that currently do not resolve; see the Network spec for the full breakdown.

Deterministic build A build process that produces bit-for-bit identical binaries given the same inputs. Bitcoin Gold (BTG) uses Gitian.

Difficulty The target value below which a block's hash must fall. Stored in the block header as nBits. The current difficulty is approximately 2.4 × 10^{11} on mainnet as of mid-2026.

E

Electrum A lightweight wallet that doesn't download the blockchain. Speaks to ElectrumX or electrs servers over Stratum.

ElectrumG The community fork of Electrum that knows about Bitcoin Gold (BTG)'s address formats, BIP44 coin type 156, and the official Bitcoin Gold (BTG) Electrum servers.

ElectrumX A Python implementation of an Electrum server. Most Bitcoin Gold (BTG) community Electrum servers run a fork called ElectrumX-Bitcoin Gold (BTG).

Equihash A memory-hard proof-of-work algorithm. Bitcoin Gold (BTG) uses Equihash-Bitcoin Gold (BTG) (N=144, K=5, personalization BgoldPoW). Solution size 100 bytes, ~2.5 GB memory per thread.

Endowment The 8 000 blocks (491 407 – 499 406) immediately after the Bitcoin Gold (BTG) fork, mined at minimum difficulty to a multisig "endowment" address. 40 % unlocked immediately, 60 % released monthly over 3 years.

F

ForkID A byte appended to a transaction's signature hash (SIGHASH) to prevent replay attacks across chains. Bitcoin Gold (BTG) uses ForkID = 79.

Full node A node that validates all blocks and transactions against consensus rules. Does not require trusting any third party for chain state.

Finalized block (v0.17.3+) A block deeper than 9 and older than 4 800 s. The node will not roll back past it. The new RPC getfinalizedblockhash returns it.

Fee The implicit value of input_value - output_value in a transaction. Paid to the miner of the block that includes the transaction.

G

Genesis block The first block of a chain. For Bitcoin Gold (BTG) mainnet: hash 00000000e0781ebe24b91eedc293adfea2f557b53ec379e78959de3853e6f9f6, time 1516123516, nonce 0x56bd5142.

Gitian The Bitcoin Core–derived deterministic build system. LXC containers, ruby orchestrator. Used for every Bitcoin Gold (BTG) release since v0.15.0.2.

GPG / PGP The signing protocol used to sign Gitian build outputs and to verify downloaded installers. Release engineers publish their PGP keys in BTCGPU/contrib/gitian-keys/keys.txt.

GPU mining The practical way to mine Equihash-Bitcoin Gold (BTG). Common miners: lolMiner, miniZ, EWBF (legacy).

H

Hard fork A consensus change that requires all nodes to upgrade. The Bitcoin Gold (BTG) launch at 491 407 and the LWMA DAA at 536 200 were both hard forks.

Hashrate The rate at which a miner (or the network) can attempt nonces. Measured in hashes/second. Equihash-Bitcoin Gold (BTG) network hashrate in mid-2026 is around 1.0–1.5 MSol/s (mega-solutions per second).

HD wallet A hierarchical-deterministic wallet (BIP32) that derives an unlimited sequence of keys from a single seed. Bitcoin Gold (BTG) wallets use BIP44/49/84 with coin type 156.

HRP Human-Readable Part of a Bech32 address. For Bitcoin Gold (BTG) mainnet: btg. Testnet: tbtg.

K

Key pair A private key (256-bit secret) and its corresponding public key (derived via secp256k1 elliptic-curve multiplication). The address is derived from the public key hash.

KYC Not a protocol concept. Mentioned because some exchanges require it before letting you withdraw to a Bitcoin Gold (BTG) address. The library does not cover KYC.

L

LevelDB The key-value store that ElectrumX uses to index transactions. Stored in DB_DIRECTORY.

Lightning Network A layer-2 payment network. BTCGPU maintains an lnd fork in the BTCGPU org, but the Bitcoin Gold (BTG) community hasn't widely adopted Lightning. Out of scope for this library.

LWMA Zawy's Linear Weighted Moving Average. The DAA used by Bitcoin Gold (BTG) since the July 2018 hardfork at height 536 200. Averaging window 45 blocks.

M

Mainnet The production Bitcoin Gold network with real economic value. P2P port 8338.

Mempool The set of unconfirmed transactions a node holds in memory. Default maxmempool for bgoldd is 300 MB.

Merkle root The root hash of the Merkle tree of all transactions in a block. Stored in the block header.

Message magic The prefix prepended to a message before signing. For Bitcoin Gold (BTG): Bitcoin Gold Signed Message:\n. Different from BTC's, so signed messages are not cross-chain valid.

Mining pool A server that distributes block-template work to multiple miners and credits shares. Speaks Stratum on 3333-3335 by convention.

N

Network magic Four bytes that identify a network at the P2P layer. Mainnet Bitcoin Gold (BTG): e1 47 6d 44. Testnet: e2 48 6e 45.

Node A process running bgoldd. May be a full node (validates everything) or a pruned node (validates everything but discards old blocks).

Nonce A field in the block header that miners vary. Extended from 32 bits (BTC) to 256 bits in Bitcoin Gold (BTG).

O

Onlynet A bgoldd config option restricting the address families the node uses. onlynet=ipv4 is the production default at bitcoingold.services.

P

P2PKH Pay-to-Public-Key-Hash. The legacy "send to address" output type. Bitcoin Gold (BTG) address prefix G.

P2SH Pay-to-Script-Hash. Allows more complex spending conditions. Bitcoin Gold (BTG) address prefix A.

P2WPKH Pay-to-Witness-Public-Key-Hash (native segwit). Bech32 address btg1.... Recommended for new wallets.

PPLNS Pay Per Last N Shares. The most common payout scheme for Bitcoin Gold (BTG) mining pools.

Pruning A node mode where old blocks are deleted to save disk space. Incompatible with txindex=1.

Protocol version The version of the wire protocol a node speaks. Bitcoin Gold (BTG): 70016. Bumped from 70015 (BTC) to support the post-fork block header format.

R

RocksDB The key-value store used by Blockbook. Currently ~140 GB for the Bitcoin Gold (BTG) index.

Reorg A reorganization of the chain. A block at height H is replaced by a different block at the same height, invalidating all descendants. Bitcoin Gold (BTG) v0.17.3 limits this to depth < 9.

Replay protection A mechanism to prevent a transaction signed for chain A from being valid on chain B. Bitcoin Gold (BTG) uses full two-way SIGHASH_FORKID with ForkID 79.

RPC JSON-RPC over HTTP. Exposed by bgoldd on port 8332 (localhost only).

RBF (Replace-By-Fee) Not enabled on Bitcoin Gold (BTG) by default. Mentioned because the option is walletrbf=1 in bitcoingold.conf if you want it.

S

Satoshi The smallest unit of Bitcoin Gold (BTG), 0.00000001 Bitcoin Gold (BTG). Same as BTC.

SIGHASH_FORKID A signature hash mode that includes the ForkID byte. Required for post-fork Bitcoin Gold (BTG) transactions.

SPV Simplified Payment Verification. What ElectrumG does: it trusts the Electrum server to provide valid block headers and merkle proofs, instead of downloading every block.

Seed (BIP39) A 12-or-24-word phrase that encodes an HD wallet's master key. Must be stored offline.

Stratum The TCP-based protocol between miners and pools. Stratum v1 is universal; Stratum v2 is emerging but not yet used on Bitcoin Gold (BTG).

Stratum v2 Out of scope for Bitcoin Gold (BTG) currently. Mining pools in this library all use Stratum v1.

T

Testnet A separate Bitcoin Gold (BTG) network (genesis 00000000e0781ebe24b91eedc293adfea2f557b53ec379e78959de3853e6f9f6, but with hard-fork at height 1 and a different magic). P2P port 18338.

Tor Bitcoin Gold (BTG) does not support Tor by default. The config listenonion=1 enables the Tor control port — but the Bitcoin Gold (BTG) fork may not have been audited for Tor. Use a separate VPN/Tor host if you need anonymity.

Transaction A signed data structure that spends one or more UTXOs and creates new ones.

txindex A node option (txindex=1) that builds an index from transaction ID to block. Required for explorers.

U

URI The bitcoingold: URI scheme for payment requests. Format: bitcoingold:<address>?amount=<btg>&label=<text>.

UTXO Unspent Transaction Output. The set of all spendable coins. The chainstate is a snapshot of the UTXO set.

V

Validation The process of checking a block or transaction against the consensus rules. Done by every full node.

Version bytes The leading bytes of a base58check address that identify the network and address type. Bitcoin Gold (BTG) P2PKH: 0x26 (38), P2SH: 0x17 (23). Different from BTC's 0x00 and 0x05.

Version message The P2P message a node sends first to identify itself. Contains protocolversion, services, nTime, and a subVer string. For Bitcoin Gold (BTG) v0.17.3: /Bitcoin Gold:0.17.3/.

W

Wallet A piece of software that holds private keys and signs transactions. For Bitcoin Gold (BTG): Bitcoin Gold Core (bitcoin-qt), ElectrumG, hardware wallets.

Witness The data structure in a segwit transaction that contains the signature and (for P2WPKH) the public key. Inherits BTC's segwit, no Bitcoin Gold (BTG)-specific changes.

Work The hashcash-style proof that a miner has tried many nonces. Equihash solutions aren't hashes, but the same "difficulty" abstraction applies.

Z

Zcash The cryptocurrency from which Bitcoin Gold (BTG) borrowed the Equihash proof of work and the post-fork block header format.

ZMQ (ZeroMQ) A high-throughput messaging library. bgoldd can publish block and transaction events over ZMQ (zmqpubhashblock, zmqpubrawblock, zmqpubrawtx). Blockbook consumes these.

ZMQ pubhashblock A bgoldd config that publishes a notification each time a new block is connected. Blockbook uses this to re-template instantly.

References