Technical Specifications

Detailed technical specifications for zERC20 components.

Specifications

• Contract Spec — Smart contract interfaces and behaviors

• ZKP Spec — Zero-knowledge circuit specifications

• ICP Storage Spec — Stealth messaging layer on Internet Computer

Quick Reference

Value Constraints

Constraint	Value	Reason
Max transfer value	2^248 - 1	Must fit in BN254 scalar field
Address size	160 bits	Ethereum address width
Merkle tree depth	40 (local) / 46 (global)	Per-token and global trees
PoW difficulty	16 bits	Burn address collision resistance

Proof Types

Proof Type	Circuit	Use Case
Root Transition	Nova	Proving new transfer roots
Batch Withdraw	Nova	Multiple withdrawals in one proof
Single Withdraw	Groth16	Single withdrawal (faster)

Key Contracts

Contract	Main Functions
zERC20	transfer, teleport, mint, burn
Verifier	proveTransferRoot, teleport, singleTeleport
Hub	broadcast, registerToken