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A Zcash consensus-level auditing mechanism that maintains supply integrity across shielded value pools by publicly tracking the net flow of ZEC entering and exiting each pool. Since shielded pool balances are encrypted and cannot be directly audited, the turnstile enforces (ZIP 209) that any block causing a pool balance to go negative is rejected. Transfers between shielded pools must pass through a transparent intermediate step for public verification.

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Turnstile Mechanism (turnstile-mechanism)
Category: Blockchain General
Definition: A Zcash consensus-level auditing mechanism that maintains supply integrity across shielded value pools by publicly tracking the net flow of ZEC entering and exiting each pool. Since shielded pool balances are encrypted and cannot be directly audited, the turnstile enforces (ZIP 209) that any block causing a pool balance to go negative is rejected. Transfers between shielded pools must pass through a transparent intermediate step for public verification.
Aliases: Turnstile
Related: Zcash, Shielded Transaction, Zcash Sapling

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Branch

Zcash

A privacy-focused cryptocurrency launched in October 2016 that pioneered the use of zk-SNARKs to enable fully shielded transactions where sender, receiver, and amount are cryptographically hidden on a public blockchain. Zcash uses a UTXO model derived from Bitcoin and maintains multiple value pools (transparent, Sapling, Orchard) with a turnstile mechanism ensuring supply integrity. Major upgrades include Sapling (2018) for efficient proofs and NU5/Orchard (2022) introducing Halo 2 to eliminate trusted setup.

UTXO Model

Open term

Branch

Shielded Transaction

A Zcash transaction where sender address, receiver address, and amount are encrypted using zk-SNARKs, providing cryptographic privacy while allowing network nodes to verify validity without learning private details. Shielded transactions operate within dedicated value pools (Sapling or Orchard), each with independent circuit designs. Users can selectively disclose transaction details to third parties using viewing keys without compromising spending authority.

Viewing Key

Open term

Branch

Zcash Sapling

A major Zcash protocol upgrade activated in October 2018 that reduced proof generation from ~40 seconds to ~2 seconds and memory from 3 GB to ~40 MB, making shielded transactions practical on mobile devices. Sapling introduced new shielded addresses, full viewing keys, diversified addresses, and decoupled proof construction from transaction signing. Its cryptographic libraries (bellman, librustzcash) became foundational for the broader ZK ecosystem.

Open term

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Blockchain General

Zcash

A privacy-focused cryptocurrency launched in October 2016 that pioneered the use of zk-SNARKs to enable fully shielded transactions where sender, receiver, and amount are cryptographically hidden on a public blockchain. Zcash uses a UTXO model derived from Bitcoin and maintains multiple value pools (transparent, Sapling, Orchard) with a turnstile mechanism ensuring supply integrity. Major upgrades include Sapling (2018) for efficient proofs and NU5/Orchard (2022) introducing Halo 2 to eliminate trusted setup.

Open term

Blockchain General

Shielded Transaction

A Zcash transaction where sender address, receiver address, and amount are encrypted using zk-SNARKs, providing cryptographic privacy while allowing network nodes to verify validity without learning private details. Shielded transactions operate within dedicated value pools (Sapling or Orchard), each with independent circuit designs. Users can selectively disclose transaction details to third parties using viewing keys without compromising spending authority.

Open term

Blockchain General

Zcash Sapling

A major Zcash protocol upgrade activated in October 2018 that reduced proof generation from ~40 seconds to ~2 seconds and memory from 3 GB to ~40 MB, making shielded transactions practical on mobile devices. Sapling introduced new shielded addresses, full viewing keys, diversified addresses, and decoupled proof construction from transaction signing. Its cryptographic libraries (bellman, librustzcash) became foundational for the broader ZK ecosystem.

Open term

Blockchain General

Unified Address

A Zcash address format (ZIP 316) that bundles multiple receiver types (transparent, Sapling, Orchard) into a single 'u1'-prefixed address, allowing the sender's wallet to automatically select the most private payment method. Unified Addresses eliminate the complexity of managing separate transparent and shielded addresses, and support diversified addresses for unlinkable payment reception from a single spending key.

Open term

Related terms

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Blockchain Generalzcash

Zcash

A privacy-focused cryptocurrency launched in October 2016 that pioneered the use of zk-SNARKs to enable fully shielded transactions where sender, receiver, and amount are cryptographically hidden on a public blockchain. Zcash uses a UTXO model derived from Bitcoin and maintains multiple value pools (transparent, Sapling, Orchard) with a turnstile mechanism ensuring supply integrity. Major upgrades include Sapling (2018) for efficient proofs and NU5/Orchard (2022) introducing Halo 2 to eliminate trusted setup.

Open term

Blockchain Generalshielded-transaction

Shielded Transaction

A Zcash transaction where sender address, receiver address, and amount are encrypted using zk-SNARKs, providing cryptographic privacy while allowing network nodes to verify validity without learning private details. Shielded transactions operate within dedicated value pools (Sapling or Orchard), each with independent circuit designs. Users can selectively disclose transaction details to third parties using viewing keys without compromising spending authority.

Open term

Blockchain Generalzcash-sapling

Zcash Sapling

A major Zcash protocol upgrade activated in October 2018 that reduced proof generation from ~40 seconds to ~2 seconds and memory from 3 GB to ~40 MB, making shielded transactions practical on mobile devices. Sapling introduced new shielded addresses, full viewing keys, diversified addresses, and decoupled proof construction from transaction signing. Its cryptographic libraries (bellman, librustzcash) became foundational for the broader ZK ecosystem.

Open term

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Blockchain General

Blockchain

A distributed, append-only ledger that records transactions in cryptographically linked blocks. Each block contains a hash of the previous block, forming an immutable chain. Nodes in the network maintain copies of the ledger and reach agreement through consensus mechanisms. Blockchains enable trustless, decentralized record-keeping without a central authority.

Open term

Blockchain General

Consensus Mechanism

The protocol by which nodes in a distributed network agree on the current state of the ledger. Common mechanisms include Proof of Work (Bitcoin), Proof of Stake (Ethereum, Solana), and BFT variants. Consensus ensures all honest nodes converge on the same transaction history despite potential network delays or malicious actors.

Open term

Blockchain General

Proof of Stake (PoS)

A consensus mechanism where validators are selected to produce blocks based on the amount of cryptocurrency they have staked (locked) as collateral. PoS is energy-efficient compared to Proof of Work. Misbehaving validators risk losing their stake (slashing). Solana, Ethereum (post-Merge), Cosmos, and Cardano use PoS variants.

Open term

Blockchain General

Proof of Work (PoW)

A consensus mechanism where miners compete to solve computationally expensive puzzles to produce blocks and earn rewards. PoW provides strong security (51% attack resistance) but is energy-intensive. Bitcoin and pre-Merge Ethereum use PoW. The difficulty adjusts to maintain target block times regardless of total network hash power.

Open term