Delegated Keys for Smart Wallets: Enabling Secure Transaction Execution from Apple Watch via ERC-4337 & Kernel Wallet

Abstract

This paper explores the potential of using modern smartwatches, particularly the Apple Watch, as an additional device for signing transactions and interacting with the blockchain. Modern crypto applications on smart-watches are limited to a read-only paradigm. The reason is a lack of security, specifically the absence of biometric verification for each transaction. When creating a classic Externally Owned Account wallet on the smartwatch side, these vulnerabilities carry a high risk of losing all of the user's funds. To solve this problem, an architecture based on the ERC-4337 standard was proposed. The proposed solution includes creating a wallet based on the kernel architecture, which allows setting access for additional keys to use funds, but within specific limitations. Consequently, one account can have several keys that can access funds. One key is the root key and has no restrictions. The established keys are called delegated and may have different restrictions. The root key can install a new delegated key or delete a previously established delegated key at any time. These delegated keys are used on the smartwatch to enable signing transactions according to the allowed rules. The main novelty of the proposed solution lies in its architecture, which enables smartwatches to be used as autonomous Web3 clients without compromising the root key, while strictly adhering to restrictions on executable operations and prioritizing security.