Introduce Smart Wallet-Advancing the Large-Scale Landing of Blockchain Applications
As the starting point of large-scale application of blockchain, many cryptocurrency wallets are adopting smart contracts and other technologies to lower the threshold for users to manage private keys. Forget private keys and mnemonics, you need a smart wallet.
Written by: Xiang Yao, Researcher of MYKEY
Peter Schiff, a well-known securities broker, tweeted bitcoin due to the loss of bitcoin, which caused a heated debate.
How did the loss happen if he didn’t misremember the password. The bug of a wallet software, mobile phone virus and even a deep disk cleaning may lead to the loss of private key storage files.Besides, if the mobile phone is directly broken or lost and the user has never backed up the private key, then the money will never come back.
Many people showed Peter Schiff the autonomy of the cryptocurrency community. However, vitalik buterin, the co-founder of Ethereum, thinks that’s wrong and believes that the community can and must provide better and safer wallets.
So what kind of wallet is better for ordinary people?
What is a wallet?
What is a wallet? In short, a wallet is key management tools + blockchain browsers + application center.
Blockchain Application Barriers
The wallet should be a ticket for ordinary people to enter the blockchain world. Nowadays, wallets have become a huge bottleneck restricting user expansion, limiting the large-scale application of blockchain.
In summary, there are the following reasons: key management difficulties, complex network pricing, decentralized multi-chain accounts.
Cross the Blockchain Barrier
How to cross the blockchain barrier, many practitioners have proposed useful solutions for the industry.
About key management, solutions represented by TEE and hardware wallets improve the security of the media; solutions based on multi-signature, secret sharing, and threshold signatures decentralize permissions and reduce single points of risk; Ethereum also proposed EIP- 2429 to introduce the social recovery function.
About network pricing, the meta-tx and ERC865 proposals (drafts) provide solutions for paying network fees and using ERC20 tokens to pay network fees.
About multi-chain account, the BIP 39/44 protocol supports the use of a single seed to derive private keys on multiple chains. However, whether it is a custodian wallet or an ordinary wallet, traditional digital wallets are difficult to balance the security and usability.
What is “smart wallet”?
Vitalik Buterin proposed in various events and articles that smart wallets are a tool to promote large-scale application of blockchain.
The “smart” of the smart wallet does not mean “smart” of artificial intelligence, but means it is based on the “smart contract”. In simple terms, the user’s assets are no longer completely controlled by a private key but are controlled by a smart contract. How to get access to the account’s asset? Is there a daily transfer limit? Can it be frozen and can it be recovered? … The solution to these problems doesn’t rely on the bottom layer of the blockchain but relies on the logic of smart contracts to achieve the definition of authorities. The advantage is that the risk is no longer highly concentrated while allowing users to make an appropriate error, such as accidentally leaking or losing the paper with the private key.
A smart wallet is software that accesses a blockchain account based on a smart contract. The user is a smart contract on the blockchain. The smart wallet securely stores the user’s private key locally, provides access to the blockchain, constructs a digital signature and realizes the transfer through the interaction with the corresponding smart contract account, and uses the blockchain application. Smart wallets are intended to lower the barriers to use the blockchain and achieve a balance between security and usability.
The differences between smart wallets, custodian wallets, and ordinary wallets:
Typical Smart Wallets
What are the current contenders on the track of smart wallets? What are their respective characteristics and advantages? According to public information, we selected three smart wallets with a large user base for analysis, which are Argent, Monolith, and MYKEY.
Argent is a London based company providing smart wallets based on Ethereum. When you register, you need to provide your mobile phone number and email address to verify your identity. The private key cannot be exported and is strictly bound to the device, allowing migration to a new device. Argent introduces Guardians mechanism, allowing users to set up relatives, friends, hardware wallets or Argent Guard as “guardian”. The Guardian mechanism enables the account to be recovered, and more than half of the Guardian can assist users in completing the lock, unlock and recovery of the wallet.
Besides, transfer limits can be set. Large transfers need to be delayed or immediately to the account with the assistance of the Guardian. The user must rely on Guardian to replace the device. Argent Guard verifies the user through mobile phone/email and does not need to pay gas fees within a reasonable range of use.
Monolith is a London company. Monolith allows users to set white list addresses, daily transfer limits, daily fee limits, etc. Users can export private keys and keep them for themselves, but Monolith has no account recovery mechanism.
Besides, Monolith uses a prepaid model, and users need to recharge ETH to the Gas Tank to pay for gas fees that may occur in the future. Besides, EU members are allowed to bind their accounts to a MasterCard savings card for offline payments.
MYKEY is based on the key ID protocol. The KEY ID protocol splits the user’s authorities into administrative authority and operative authority. The administrative authority can only modify account authority without operating the asset directly and the operative authority is used for daily operations.
MYKEY allows users to export the admin key (recovery phrase) but does not allow exporting the operation key, which can be synchronized to the new device. Besides, MYKEY Lab is an emergency contact for real-name users by default, which can assist users to restore the account and other operations.
At the network fees level, MYKEY offers a certain amount of free fee, and also offers targeted free fee for applications. For example, users who meet the conditions can enjoy up to four free times of Ethereum transfers every month. When used up, they need to recharge or get network fees by participating in activities to continue to use.
Comparison of Common Smart Wallets
Based on different application scenarios and target users, the three wallets have their own characteristics, each with its advantages in terms of security and usability:
Generalized Smart Wallets
Is “Smart Wallet” the only way for the next generation’s wallet? Some non-smart wallets still allow users to better manage their private keys and recover their accounts through social networks or trusted third-party services in the case of guaranteeing their autonomy, such as HTC Zion, ZenGo, Torus, etc
HTC Zion is a custom HTC mobile wallet. Zion is special in two aspects: (1) Both 12-word recovery phrase and signing transaction will be operate in trusted execution environment (TEE); (2) Break, encrypt and share your recovery phrase to your trusted contacts.
ZenGo uses threshold signatures and biometrics to lower the threshold for users to keep private keys. In short, ZenGo stores a private key on the client side and another private key on the server side. When sending a transaction, the user gets a partial signature locally and sends it to the server. The final transaction is constructed by the method of signature aggregation.
The private key of the ZenGo client is encrypted by another key and then transmitted to the cloud (such as iCloud) for saving. The encryption key is hosted by a third-party face recognition security agency. When users lose their mobile phones, they need to pass the face verification of the security agency, and then decrypt the private key stored in the cloud.
Torus is committed to key management and uses a publicly verifiable secret sharing (PVSS) scheme to host private keys in different trusted institutions. When the user loses the private key, the user can submit a recovery request. The trusted institution will give the segmented private key after verifying the user’s identity. When enough trusted institutions approve, the private key can be recovered.
Although these wallets do not use smart contract technology, they are still wallets that use new technology to lower the threshold for users to keep private keys, which may be called “smart wallets” in a broad sense.
Please forget the private key and mnemonic, smart wallet can make it easier for users to use the blockchain. At present, the smart wallets mentioned in this article have been open for users. The official websites is as follows:
Vitalik Buterin: Especially optimistic about zero-knowledge proof, and hope to use smart wallets in 2 years. https://bit.ly/2PzXMXW
 In the era of digital currency, the memory and future reflected by a wallet. https://bit.ly/371hfaJ
 Argent: Why smart contract wallets are the future. https://bit.ly/2LO5bSp
 A new era for crypto security. https://bit.ly/36Yvj4I
 Where is the promising land of the digital world? https://bit.ly/2rDdx8C
 Learn to think about the concepts of secret sharing, multi-signature and threshold signature. https://bit.ly/36nkysI
 MYKEY: a trustless beauty of balance — a brief introduction to the design of KEY ID protocol. https://bit.ly/36sthKl