import { HD, Hash, Utils } from "@bsv/sdk";
import type { PrivateKey, PublicKey } from "@bsv/sdk";
/**
* Get a signing path from a hex number
*
* @param hexString {string}
* @param hardened {boolean} Whether to return a hardened path
* @returns {string}
*/
const getSigningPathFromHex = (hexString: string, hardened = true) => {
// "m/0/0/1"
let signingPath = "m";
const signingHex = hexString.match(/.{1,8}/g);
const maxNumber = 2147483648 - 1; // 0x80000000
if (!signingHex) return signingPath;
for (const hexNumber of signingHex) {
let number = Number(`0x${hexNumber}`);
if (number > maxNumber) number -= maxNumber;
signingPath += `/${number}${hardened ? "'" : ""}`;
}
return signingPath;
};
export const friendPrivateKeyFromSeedString = (
seedString: string,
xprv: string,
): PrivateKey => {
if (!xprv) {
throw new Error("no xprv!");
}
// Generate a key based on the other users id hash
const seedHex = Utils.toHex(Hash.sha256(Utils.toArray(seedString)));
const signingPath = getSigningPathFromHex(seedHex);
const hdPrivateFriendKey = HD.fromString(xprv).derive(signingPath);
return hdPrivateFriendKey.privKey;
};
export const friendPrivateKeyFromMemberIdKey = (
memberIdKey: PrivateKey,
targetBapId: string,
) => {
return memberIdKey.deriveChild(memberIdKey.toPublicKey(), targetBapId);
};
export const friendPublicKeyFromSeedString = (
seedString: string,
xprv: string,
) => {
return friendPrivateKeyFromSeedString(seedString, xprv).toPublicKey();
};