The 'Trojan Horse' in Ethereum Fusaka Upgrade: How to Turn Billions of Mobile Phones into Hardware Wallets? one ️⃣ You actually had a 'hardware wallet' in your pocket a long time ago The phones and computers we use in our daily lives are actually equipped with specialized security chips. For example, the "Secure Enclave" in iPhone or Keystore/Trust Zone/StrongBox in Android phones. This independent physical area is commonly referred to as TEE (Trusted Execution Environment). Its characteristic is' only in, no out ': the private key is generated inside and will never leave this physical area, and external parties can only request it to sign the data. This is actually the standard for hardware wallets. And these chips commonly use an industry standard algorithm curve selected by NIST (National Institute of Standards and Technology) for signature: secp256r1. This is also the cornerstone behind WebAuthn and FIDO2 (such as your fingerprint login, FaceID). two ️⃣ A gap of only one letter apart Embarrassingly, Ethereum does not natively support this mainstream secp256r1. At that time, the Bitcoin community chose the relatively obscure secp256k1 due to concerns about the possibility of a "national backdoor" in the NIST curve, so Ethereum followed the tradition of this curve when designing its account system. Although r1 and k1 may appear to be only one letter apart, mathematically they are two completely different languages. This leads to a huge pain point: the security chip in your phone looks confused towards Ethereum, as it cannot directly sign Ethereum transactions. three ️⃣ Since we can't change the hardware, let's be 'compatible' with it in this version Ethereum obviously cannot force Apple or Samsung to change their chip design to adapt to secp256k1, the only way is for Ethereum to adapt to secp256r1 on its own. Can we use smart contracts to write code to verify r1 signatures? In theory, but the mathematical calculations are too complex, and running one verification may consume hundreds of thousands of gas, which is completely unusable economically. So, in the Fusaka upgrade, developers resorted to a big killer: precompile contracts. This is equivalent to opening a 'backdoor' or 'cheat' in the Ethereum Virtual Machine (EVM). Instead of letting EVM calculate step by step, it is better to directly write this verification function into the underlying code of the client. Developers only need to call specific addresses to complete verification at an extremely low cost. In EIP-7951, this cost is fixed at 6900 Gas, which is directly reduced from tens of thousands to several thousand, finally entering the range of "daily use in real products". four ️⃣ The final puzzle of account abstraction The implementation of this EIP means that we can finally sign and authorize smart accounts on Ethereum in the TEE environment of mobile phones. It should be noted that this does not apply to EOA addresses like MetaMask that you are currently using (as their public key generation logic is still k1). It is specifically designed for "Account Abstraction" (AA Wallet). In the future, your wallet will no longer be a string of mnemonic words, but a smart contract. This contract states: As long as the fingerprint (r1 signature) is verified to be correct, the transfer is allowed. '' five ️⃣ summary EIP-7951 may not make mnemonics disappear overnight, but it has finally removed the biggest stumbling block on the path to Ethereum's widespread adoption. Before this, the cruel multiple-choice question before users was always: Do you want to have "bank grade" autonomous security? You have to spend money to buy a OneKey, Keystone, or Ledger, and also keep mnemonic words like a gold bar; Do you want the smoothest experience? You can only store your coins in an exchange or custodial wallet, at the cost of surrendering control (sacrificing decentralization). After Fusaka upgrade, this multiple-choice question will no longer exist. With the implementation of EIP-7951, 'mobile phone as hardware wallet' will gradually become a reality. For the future billion new users, they may not even need to know what a 'private key' is or face the psychological pressure of copying 12 words. They just need to swipe their face and press their fingerprint like they usually do when buying coffee, and the iPhone security chip behind them will call secp256r1 to sign the transaction and complete the verification through Ethereum's native precompiled contract. This is the right posture for Ethereum to embrace the next billion users: instead of arrogantly requiring users to learn complex cryptography, it is to put down its posture to be compatible with the general standards of the Internet and take the initiative to enter the pockets of users.