2.1 Adversary Model
Abyss assumes a global passive adversary with full read access to the blockchain. This includes the ability to observe:- All transactions and events
- All calldata and emitted logs
- All historical state transitions
- Timing, ordering, and value flows
2.2 Privacy Objective
The primary privacy objective of Abyss is unlinkability, not anonymity of participation. Formally, the protocol aims to ensure that, given:- a deposit transaction ( D )
- a withdrawal transaction ( W )
2.3 Cryptographic Enforcement
Unlinkability is enforced through:- Commitment schemes binding deposits to secrets
- Nullifiers preventing double-spends without revealing identity
- ZK-SNARK proofs asserting valid state transitions without disclosing witness data
2.4 Anonymity Set Assumptions
Privacy strength scales with the size and diversity of the anonymity set. Abyss assumes:- Multiple independent users
- Overlapping deposit and withdrawal activity
- Non-pathological usage patterns
2.5 Aside: Privacy-Preserving Payments
Abyss is explicitly designed to support private payments, not just private asset movement. In traditional on-chain payments, merchants receive funds from addresses whose entire transaction history is immediately visible. This creates unacceptable information leakage: balances, prior counterparties, historical behavior, and even inferred identity. Abyss enables a different model. Users can pay merchants via withdrawals that are cryptographically valid yet unlinkable to prior activity. Merchants receive funds without learning anything about the payer’s history beyond the payment itself. This has direct implications for:- Consumer payments
- Merchant settlement
- Payroll and contractor compensation
- Subscription and recurring billing primitives
2.6 Explicit Non-Goals
Abyss does not attempt to:- Obfuscate consensus participation
- Hide contract interactions unrelated to transfers
- Provide identity anonymity at the network layer

