Last modified: Fri Aug 16 2019 11:27:04 GMT+0000 (Coordinated Universal Time)

How to keep the Write API secure

In this tutorial, you will learn a few security tips regarding Winding Tree Write API and wallet management.

Requirements

Step by step

Ethereum's best practice is to sign every transaction locally, in a way that your private key never leaves your computer. But in an environment where you need to issue many transactions, it is just not feasible to sign everything by hand.

Another best practice is to protect the private key by a passphrase. That's exactly what the wallet in a Web3 Secret Storage format enables us. But this wallet file has to inevitably be stored in a software, in our case Write API.

And it is also inevitable that you have to decrypt the wallet file to extract the private key when you need to sign a transaction.

The Write API design tries to at least decouple the wallet and the passphrase as much as possible. That's why you have to provide your wallet passphrase with every request. The private keys are only exposed in-memory for the shortest time possible.

Here are some more tips on how to make your Write API instance as secure as possible.

Network isolation

Since the Write API stores an Ethereum wallet for every account and it can possibly hold dozens or hundreds of accounts and therefore wallets, it can easily become an attacker's target.

By design, an attacker can try to crack the passphrases totally offline with as much computing power as she can.

That is why we recommend to run the Write API in a secure isolated network and prevent access to it from the public internet.

Funds

Because you can never be sure that your wallets from Write API are totally safe, you should take an extra measure and keep the amount of ETH in them limited only to cover the necessary costs.

If you hold large amounts of ETH, you should never make them available in a wallet stored in any software.

That is why we recommend to keep the ETH funds assigned to each wallet to a bare minimum.

Data isolation

Write API allows you to control many records in Winding Tree Index under a single Ethereum wallet. That means that such wallet is an owner of all of the records in Winding Tree Index and if it gets compromised, an attacker will get control of all of these records.

It is a best practice to have every record managed by a different Ethereum wallet. This also brings you performance gains as it will allow you to publish changes for multiple records to the same Ethereum block.

That is why we recommend to associate a particular wallet with only one Write API account and use that account to manage only one record in Winding Tree Index.

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