Generate Private Key for Loom Using BIP39

bip39-loom.cs

// Add this function to Loom SDK CryptoUtils.cs
public static byte[] GeneratePrivateKey(byte[] seed) {
    byte[] publicKey32;
    byte[] privateKey64;
    Ed25519.KeyPairFromSeed(out publicKey32, out privateKey64, seed);
    return privateKey64;
}

// You can use any BIP39 implementation. In this example i used https://github.com/ByronAP/BIP39.NET-Portable
var mnemonic = "spin sunset pact nature enhance include fatigue occur blind wire inner foot";
var importer = new Bitcoin.BIP39.BIP39(mnemonic);
var seed = new byte[32];
for(int i = 0; i < 32; ++i) {
    seed[i] = importer.SeedBytes[i]; // use only first 32 bytes
}

PrivateKey = Loom.Unity3d.CryptoUtils.GeneratePrivateKey(seed); // generate private key - ready to use.