How can manually generate same address from mnemonic as subkey without it?

Question

Can someone tell me how can I generate a secret/privateKey/miniSecretKey, publicKey without subkey the tool from a mnemonic?

I am working on a c# implementation of the wallet generation and I'd appreciate any help :) The goal is: using the schnorrkel signature and generate the same private/pubkey as the subkey does.(the address generation is working, but i can't derive the correct seed, and i even need it in 64byte version)

The mnemonic i am trying to use and get the results are these: maple rather inject cage food unable enter economy adapt mandate novel start

  Network ID/version: substrate
  Secret seed:        0xce456c3f305bf2c31868b1f51eb297e8b304551f1e456758cfa555d0040b31f7
  64-byte secret:     0x1B04EA5667F6D63B7D405503651F56129B64ED148336F35EECCA53716B872B0B542E9D846415B636BB1741C22C8BCA827CEF9D170B9E671E36B60345D18B3894
  Public key (hex):   0xa805c199eaa3d4d3f0865691e94b3ce4a508ee68aef6d7b42642d0d5d389667d
  Account ID:         0xa805c199eaa3d4d3f0865691e94b3ce4a508ee68aef6d7b42642d0d5d389667d
  SS58 Address:       5Fs1cSCX2ZDvtfC6wvrWWFoQDRdcESLuoTyYofdE1AM7LVhD

so the 64-byte secret how can be generated from this mnemonic "manually"? (i can't really read rust yet btw)

Answer 1

Just a little bit of Rust :) https://github.com/paritytech/substrate-bip39/blob/eef2f86/src/lib.rs#L44L61

See the README for rationale behind this entropy to seed method.

Answer 2

Besides Joe's Rust implementation, you can also check how it is implemented in PolkadotJS#keyring and py-substrate-interface#Keypair:

from substrateinterface import Keypair


mnemonic = 'maple rather inject cage food unable enter economy adapt mandate novel start'
keypair = Keypair.create_from_mnemonic(mnemonic)

print(
    f'Secret seed:\t\t0x{keypair.seed_hex}\n' + \
    f'64-byte secret\t\t0x{keypair.private_key.hex()}\n' + \
    f'Public key (hex):\t0x{keypair.public_key.hex()}\n' + \
    f'Account ID:\t\t0x{keypair.public_key.hex()}\n' + \
    f'SS58 Address:\t\t{keypair.ss58_address}'
)

Answer 3

Thanks for the answers, i was kinda aware of these repos, but still thx :)

Since i used NBitcoin lib in c# to genereate pk pairs and it uses a different algo the derive seed, i had to calculate the entropy first, then use the

var pbkdf2 = new NBitcoin.Crypto.Pbkdf2(new System.Security.Cryptography.HMACSHA512(entropy), salt2, 2048);
var seed = pbkdf2.Read(32);
var minis = new Schnorrkel.MiniSecret(seed, ExpandMode.Ed25519);

take the first 32 byte, then create a Schnorrkel.MiniSecret and use the public key to generate the address... stg like this (syntax err, i know...):

...
var ss58Prefixed = new List<byte> { 0x53, 0x53, 0x35, 0x38, 0x50, 0x52, 0x45, networkprefix, publickeybytes };
var blake2bHashed = HashAlgorithm.Blake2b_512.Hash(ss58Prefixed.ToArray());
var addressBytes = [prefix, publickeybytes, blake2bHashed[..2]]
var address = Encoders.Base58.EncodeData(addressBytes);
...

ofc now i have an another issue: transaction fails in case of kusama and westend chains