Antminer X9
Monero ASIC Miner
1000KH
HASHRATE
2.47W/KH
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2470W
POWER
£860.71
EST. MONTHLY
205
DAYS
EST. ROI
This guide explains BIP 142 Address Format for Segregated Witness in plain English. It covers the problem behind the BIP, why it matters and whether the proposal is part of Bitcoin today.
TL;DR
- What it is: BIP 142 proposed Base58-encoded addresses for native Segregated Witness programs, combining an address version, witness version, padding, a 20-byte or 32-byte program and a four-byte checksum. The Application-layer proposal is Closed.
- Why it matters: BIP 142 documented an early native SegWit address route, but the ecosystem deployed Bech32 and later Bech32m. Treat its Base58 format as archival evidence, not a payment standard.
- Current position: The Application-layer proposal is Closed.
BIP 142 Address Format for Segregated Witness in simple English
BIP 142 Address Format for Segregated Witness: The proposed payload carried a one-byte network-specific address version, one-byte witness-program version, a zero padding byte and either a 20-byte public-key hash or 32-byte script hash.
Simple example
A node operator is checking BIP 142 Address Format for Segregated Witness. The resulting Base58 strings had fixed lengths but unfamiliar prefixes. Backward incompatibility was intended to fail clearly: an old wallet would reject the new address instead of silently paying the wrong script.
Key terms in plain English
- BIP:
- Bitcoin Improvement Proposal: a document describing a proposed rule, standard or process. Its status must be checked separately.
- Node:
- A computer running Bitcoin software that checks data and communicates with other peers.
What the address encoded
The proposed payload carried a one-byte network-specific address version, one-byte witness-program version, a zero padding byte and either a 20-byte public-key hash or 32-byte script hash. Double-SHA256 supplied the four-byte checksum. The resulting Base58 strings had fixed lengths but unfamiliar prefixes.
P2WPKH and P2WSH outputs
BIP 141 version-zero witness outputs use OP_0 followed by a 20-byte or 32-byte program. The shorter form commits to a public key hash; the longer form commits to a witness script. The address is only a transport encoding: wallets must still construct the exact scriptPubKey and validate network and witness length.
Transition from nested SegWit
P2SH-wrapped SegWit let older senders pay a familiar Base58 P2SH address, but added redeem-script overhead. BIP 142 sought a native address without the wrapper. Backward incompatibility was intended to fail clearly: an old wallet would reject the new address instead of silently paying the wrong script.
Why Base58 was not retained
Embedding network, witness version and program type through Base58 version prefixes created many prefix assignments and offered limited error localisation. Bech32 adopted a human-readable network prefix, data-part witness version and stronger structured checksum. Later Bech32m adjusted checksum rules for witness versions one and above.
Closed status matters
A syntactically decodable BIP 142 string is not a supported Bitcoin mainnet address. Wallets, exchanges and explorers should not resurrect the draft mapping or guess a conversion. Recovery requires decoding the historical payload, independently verifying the intended witness program and producing a current supported destination.
Operational migration
Inventory databases, QR parsers and validation libraries for old experimental strings. Keep raw values read-only, label them historical and require two-person verification before any conversion. Compare derived scriptPubKeys rather than displayed characters, and never infer network from a screenshot or truncated prefix.
How specialists test it
Developers test the proposal with made-up data on an isolated test network. They check normal cases and deliberately invalid cases. Different implementations should reach the same result before anyone relies on the proposal.
Frequently asked questions
What is the main point of BIP 142 Address Format for Segregated Witness?
BIP 142 Address Format for Segregated Witness: The proposed payload carried a one-byte network-specific address version, one-byte witness-program version, a zero padding byte and either a 20-byte public-key hash or 32-byte script hash.
For BIP 142 Address Format for Segregated Witness, what should a beginner know about what the address encoded?
The proposed payload carried a one-byte network-specific address version, one-byte witness-program version, a zero padding byte and either a 20-byte public-key hash or 32-byte script hash.
For BIP 142 Address Format for Segregated Witness, what should a beginner know about p2wpkh and P2WSH outputs?
BIP 141 version-zero witness outputs use OP_0 followed by a 20-byte or 32-byte program.
For BIP 142 Address Format for Segregated Witness, what should a beginner know about transition from nested SegWit?
P2SH-wrapped SegWit let older senders pay a familiar Base58 P2SH address, but added redeem-script overhead.
Conclusion
BIP 142 documented an early native SegWit address route, but the ecosystem deployed Bech32 and later Bech32m. Treat its Base58 format as archival evidence, not a payment standard.
Primary sources
Check the current specification status and the documentation for the exact implementation you operate before moving production funds or changing a mining node.
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