Bitcoin Forum

There are 70 blockchains, you need to generate addresses and private keys from them using Brainwallet alone.

Is there any information on this subject? Or do you need to separate each open source project?

Maybe some libraries.

Similar to Private Key > address

To store coins from multiple blockchains, you need to install something called a "multicurrency crypto wallet." These are hierarchically deterministic wallets that support the multi-account derivation scheme described in the BIP44 standard. This works like this: your wallet generates a big random number (entropy) using in-built RNG and from this number it produces thousands of private keys, public keys, and addresses for different blockchains. All these keys can be recreated if you restore your wallet by entering exactly the same random number. This random number is usually shown to users as a set of words that can be easily written down on a piece of paper. If you want, you can try to memorize these words, but given that human memory is very fallible, it is not recommended that you keep sensitive information in your memory. Brainwallets, which you are talking about, work in a slightly different way. They are extremely insecure because instead of using a long random number generated by software means, they take human-generated data as entropy to produce other keys. Their security is therefore totally dependent on human's ability to produce random data.

Most coins use a 256-bit random value as a private key, so any method for generating a brain wallet will generally work for all of them. However, the derivation of an address from the private key varies greatly, so each coin would need to be handled separately.

I would use https://iancoleman.io/bip39/

It is not a brainwallet but this tool will do what you are asking for.

You can choose which blockchain you want and the website will generate the privatekeys and public addresses.

This iancoleman is a great website but how can we trust the owner? This website requires you to import your recovery seed to get access to your address private key, not a bad idea at all but I lost money in my wallet and I have use this wallet on iancoleman before, when the theft happened my mind come straight to iancoleman, people should stick with wallets that give users private keys and recovery seed in one like metamask and trust wallet so no need for iancoleman.

You shouldn’t trust anyone. Ian Coleman is a bitcoin developer,  and all of his code is open source.

Don't trust. Verify it.

You should only run it in an offline computer and download it first.

If you are afraid about your backup seed or private key are being stolen then there is a way to protect them while using this iancoleman tool just download the source code directly as already suggested above or just download the whole page of https://iancoleman.io/bip39/ and turn off your wifi or internet before you use the tool for safety purposes.

And actually, this tool was already created a few years ago and no one still complains about this tool you can anytime check the source code which is open source under their Github page.
Don't compare this tool with Metamask and Trust wallet because they are totally different.

The easiest solution is to buy a hardware wallet where you can manage thousands of digital currencies from one wallet.
You can find a multi-currency wallet, but most of them are closed source and therefore you need to trust the developers, hardware wallets provide you with better security.

If by Brainwallet you mean using a password like "12346" and then generating a private key for all the cryptocurrencies, it's a bad idea.