Security & Trust

Simple Replay Protection

Transactions include chain ID preventing replay across networks — signing on Ethereum won't accidentally work on Polygon. Design implications: show network badge prominently during signing, warn if signing for unexpected chain, auto-detect chain mismatches between wallet and dApp. Design decisions: whether to block cross-chain mistakes entirely or allow with confirmation — power users want flexibility, novices need protection.

Stages: Status & Confirmation

Signed Data Standard

Users sign off-chain messages to authorize actions without gas — login, approve listings, multisig confirmations. Design implications: show clear 'Sign Message' vs 'Approve Transaction' distinction, display human-readable message content before signing, indicate which dApp/contract will validate the signature. Design decisions: balance security warnings (phishing risk) against friction — too many warnings cause blindness, too few enable exploits.

Stages: Authentication & Identity

Standard Signature Validation for Contracts

Smart contract wallets (Safe, Argent) can sign messages like EOAs — unlocks gasless listings, off-chain voting for multisigs. Design implications: don't assume signer = EOA, show 'Wallet Type: Smart Contract' indicator, support signature verification loading states. Design decisions: how to handle async signature verification vs instant EOA checks — may need pending/confirming states in UI.

Stages: Authentication & Identity

ChainID Opcode

Smart contracts can verify which chain they're on, enabling chain-aware logic for bridges and L2s. Design implications: display chain context in multi-chain interfaces, show 'Supported Networks' clearly, indicate when contract behavior varies by chain. Design decisions: whether to expose chain-specific features or abstract them away — transparency vs simplicity tradeoff.

Stages: Status & Confirmation

Author NFTs

NFT metadata includes verified author consent signatures — proves creator agreed to be credited, prevents fake attributions. Design implications: show 'Verified Author' badge with proof link, display multiple co-authors, indicate consent verification status. Design decisions: how to handle unverified vs verified authors — warning indicators, whether to allow display of unverified claims.

Stages: Authentication & Identity

Refundable Tokens

NFT/token purchases include refund windows like traditional e-commerce — buyers can return within deadline. Design implications: show 'Refundable until [date]' badge on listings, add 'Request Refund' button in owned items, display refund countdown timer. Design decisions: whether refund status affects resale UI — should refundable items show different on marketplaces, how to handle partial refund eligibility.

Stages: Asset Management

Refundable Fungible Token

Token sales use escrow with built-in refund mechanism — funds locked until conditions met, buyers protected from rugpulls. Design implications: show escrow status (Funded/Running/Success/Failed), display refund eligibility, visualize lock period timeline. Design decisions: how much escrow complexity to expose — show full state machine or simplified status, balance transparency with cognitive load.

Stages: Asset Management

Guard of NFT/SBT

NFT owners can set a 'guard' address that controls transfers — enables anti-theft (cold wallet guard), lending collateral, SBT recovery. Design implications: show 'Protected by Guard' indicator, display guard expiry, add guard management UI for setting/removing. Design decisions: how to communicate transfer restrictions — warning when guard active, explain why transfer button disabled, guard vs owner permission clarity.

Stages: Asset Management

Multi-privilege Management NFT

NFTs carry multiple transferable privileges (discounts, access, votes) that can be shared or assigned separately from ownership. Design implications: show privilege list with individual expiry dates, add 'Share Privilege' action, display privilege holder vs token owner. Design decisions: how to visualize privilege spreading/cloning — referral tree view, privilege inheritance tracking, balance utility discovery with UI complexity.

Stages: Approving & Permissioning

Verifiable AI-Generated Content Token

AI-generated NFTs include cryptographic proof linking output to specific model and prompt — verifiable provenance for AI art. Design implications: show 'AI-Generated' label with model info, display original prompt, add 'Verify Proof' button. Design decisions: how prominent to make AI disclosure — regulatory requirements vs aesthetic concerns, whether to filter/highlight AI content separately.

Stages: Specialized Interactions

Prevent Ticket Touting

Event tickets can only be transferred through authorized resellers — prevents scalping, enables price caps on secondary sales. Design implications: show 'Official Resale Only' indicator, direct to authorized resale channels, display ticket status (Sold/Resell/Void/Redeemed). Design decisions: how to handle unauthorized transfer attempts — educational messaging about why blocked, clear path to legitimate resale options.

Stages: Specialized Interactions

Access Control Registry

Centralized registry manages roles across multiple contracts — admins grant/revoke permissions from single dashboard. Design implications: build unified permission management UI, show role assignments across contracts, display audit trail of permission changes. Design decisions: how granular to make role visibility — show all roles or just relevant ones, balance admin power with principle of least privilege.

Stages: Approving & Permissioning