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Block format

A Navio block is a Bitcoin-shaped block with BLSCT-aware transaction bodies.

CBlockHeader (80 bytes)
├── nVersion            int32
├── hashPrevBlock       32 bytes
├── hashMerkleRoot      32 bytes
├── nTime               uint32
├── nBits               uint32    compact difficulty target
└── nNonce              uint32    Header nonce (legacy Bitcoin field; PoPS proof lives in block.posProof, not here)

Identical to Bitcoin at the byte level. All BLSCT / PoPS blocks use the same 80-byte header shape. Consensus-critical data that cannot fit in the header (the ZK proof itself) lives in block.posProof, appended outside the header.

Block body

CBlock
├── Header              80 bytes
├── posProof            blsct::ProofOfStake (set-membership + range proof)
├── vtx[]               CTransaction[]
│   ├── vtx[0]          Coinbase (zero-value output)
│   ├── vtx[1]          Coinstake (zero-value marker output, then reward outputs)
│   └── vtx[2..]        Regular BLSCT transactions
└── witness commitment  embedded in coinbase if any segwit-style fields used

Field order per primitives/block.h: READWRITE(obj.posProof, obj.vtx) after the header.

Coinbase

The first transaction is the coinbase. Its single output is zero-value; the real staker reward is paid in the coinstake. vin[0].prev_out is the null marker (32 zero bytes).

Coinstake (PoPS)

Every block carries a blsct::ProofOfStake posProof field (see primitives/block.h). Structural markers:

vtx[0] (coinbase) — null prev_out, zero-value output
vtx[1] (coinstake) — first output is zero-value nonstandard marker
block.posProof — encoded ZK proof (set-membership + range proof)

Key points about PoPS — applies to the current BLSCT networks (mainnet, testnet, and blsctregtest):

  • posProof does not identify the staker's locked UTXO. It contains a set-membership proof over the current staked-commitment set plus a range proof binding a hidden stake amount to the block's kernel-hash eligibility threshold.
  • Eligibility is verifiable with zero-knowledge — no validator identity, amount, or cross-block linkage is revealed.
  • Coinstake outputs pay the network's current PoPS subsidy plus returned principal as BLSCT outputs addressed to sub-addresses in the staker's staking pool (account -2).

Full math, verifier equations, serialisation, source-tree map: BLSCT → Proof-of-Private-Stake.

Fee handling

Source Fate
Regular BLSCT transaction fees Burned
OP_RETURN outputs Burned — provably unspendable
Community fund (legacy Navcoin at mainnet genesis) Burned
Staking rewards earned on migrated supply during swap window Burned

See Consensus for the full economic picture.

Merkle commitment

Standard Bitcoin-style Merkle tree of transaction hashes, committed to in the header. BLSCT transactions hash via their canonical serialised form including BLSCT-specific fields.

Block explorer view

The navio-blocks indexer categorises blocks via:

block.type = "PoPS"  # on BLSCT / PoPS chains

BLSCT-aware outputs display as Hidden amounts. Transparent outputs (genesis-time bootstrap outputs that seed the PoPS staker set on testnet cuts, and OP_RETURN burns) show values normally. See supply tracking.

Serialisation

  • src/primitives/block.h — CBlock, CBlockHeader.
  • src/blsct/pos/ — PoS / PoPS consensus rules.
  • src/consensus/params.h — chain-level constants (block time, max size, activation heights).

Current chainparams: mainnet uses a bootstrap PoW window through height 100, then PoPS with nPosTargetSpacing = 120 and nBLSCTBlockReward = 8 NAV; testnet uses a bootstrap PoW window through height 1000, then PoPS with nPosTargetSpacing = 60 and nBLSCTBlockReward = 4 NAV.