The Ghost Whale: Practical Privacy with Selective Disclosure on the Post-Pectra EVM
Abstract
GhostShard is a privacy protocol for post-Pectra Ethereum Virtual Machine (EVM) chains that introduces UTXO-style privacy to standard externally owned accounts (EOAs) without requiring zero-knowledge circuits, trusted setup ceremonies, mixer pools, shielded state trees, or custom execution environments.
The protocol is based on the observation that privacy can emerge from ownership topology rather than cryptographic hiding of transaction contents. GhostShard decomposes account ownership into one-time-use stealth accounts called shards. Every deposit creates a new shard, while every spend consumes existing shards and creates fresh replacement shards. Asset transfers are executed through mesh transactions: atomic EIP-7702 transactions that combine multiple input shards, multiple output stealth addresses, and multiple ERC-5564 announcements into a single execution unit. This many-to-many transaction structure eliminates deterministic relationships between inputs and outputs while preserving full self-custody.
GhostShard combines ERC-5564 stealth addressing, EIP-7702 delegation, and sponsored transaction execution to provide private transfers for native assets, ERC-20 tokens, and ERC-721 NFTs. The protocol introduces a randomized coin-selection engine, opportunistic shard compression, recipient/change indistinguishability, and selective disclosure mechanisms for optional auditability.
An implementation of GhostShard v0 was deployed on Arbitrum Sepolia and evaluated across twenty-two measured transactions spanning native ETH, ERC-20, and ERC-721 transfers. Experimental results show that total gas consumption scales linearly with transfer count, with transfer commands explaining approximately 97% of observed gas variance. Verification and execution costs exhibit predictable linear behavior, while transaction bundling produces substantial amortization benefits, reducing effective gas per transfer by more than 3× across the measured range. Analytical evaluation further shows that ERC-5564 view tags reduce announcement-discovery cryptographic workload by approximately 256× relative to naive scanning.
These results demonstrate that disposable ownership can be implemented within the existing EVM account model while maintaining self-custody, preserving composability, and achieving predictable scaling characteristics without relying on zero-knowledge systems.
Keywords: Privacy, EIP-7702, ERC-5564, Stealth Addresses, Account Abstraction, Ethereum, UTXO, NFT Privacy, Gas Sponsorship, Disposable Ownership.