Convert Seed Hex to Mnemonic

[anarkrypto]

Hi!

I've been working on a mobile wallet with react-native, using Ethers as a base.

We don't want to use passwords. I believe that the best solution for our case is to store the seed in hex with expo-secure-store.

In my opinion the mnemonics should only be used to allow export / import of the wallet. Also the hexadecimal format seems more efficient for storage. I can then generate the wallet with HDNode.

However, ethers.js does not have a tool to convert the seed from hex to mnemonic.

I don't want to have to store the mnemonic. Any suggestion ?

[ricmoo]

You probably want these functions and this constructor. :)

[anarkrypto]

@ricmoo, when importing with HDNode.fromSeed the mnemonic is always null

[ricmoo]

You cannot convert a seed to a mnemonic. If you are looking to store bytes and have access to the mnemonic you need to store the entropy. I’ve tried illustrating the directions here:

entropy <=> mnemonic => seed

The seed is the hash of the mnemonic, so there is no way to reverse it. The entropy and mnemonic are interchangeable though.

Make sense?

[anarkrypto]

Now it makes perfect sense! I thought the mnemonic was extracted from the seed hex (bytes) and not the other way around! Nor had I found standards for this.

I'll store the entropy then. Thanks a lot for the help @ricmoo!

[ricmoo]

If you are looking for some light reading: BIP 39. ;)