feat: implement HDKey ID

README.md

@@ -239,6 +239,8 @@ However, production code will look more like this:
       RECEIVE, CHANGE
   async fromSeed(seedBytes, opts)   // depth-0 hdkey (Wallet)
   async fromXKey(xprv||xpub, opts)  // depth-4 hdkey (XKey)
+  async toPublic(xKey)
+  async wipePrivateData(xKey)
   async toWif(privBytes, opts)
   async toAddr(pubBytes, opts)
   async toXPrv(xprvKey, opts)
@@ -415,6 +417,22 @@ let xkey = await DashHd.fromXKey(xprvOrXPub, options);
 }
 ```
 
+### `toPublic(xkey)`
+
+Creates a copy of the HD Key with `privateKey` set to `null`.
+
+```js
+let xpubKey = await DashHd.toPublic(xprvKey);
+```
+
+### `wipePrivateData(xkey)`
+
+Performs an in-place secure erase of the private key memory.
+
+```js
+await DashHd.wipePrivateData(xprvKey);
+```
+
 ### `toWif(privBytes, opts)`
 
 Wrapper around `DashKeys.encodeKey(keyBytes, options)` to Base58Check-encode a

dashhd.js

@@ -6,6 +6,8 @@
  * @prop {HDFingerprint} _fingerprint
  * @prop {HDFromSeed} fromSeed
  * @prop {HDFromXKey} fromXKey
+ * @prop {HDToId} toId
+ * @prop {HDToIdBytes} toIdBytes
  * @prop {HDToAddr} toAddr
  * @prop {HDToWif} toWif
  * @prop {HDToXPrv} toXPrv
@@ -14,6 +16,7 @@
  * @prop {HDToXKeyBytes} toXPubBytes
  * @prop {HDUtils} utils
  * @prop {HDWipePrivates} wipePrivateData - randomizes private key buffer in-place
+ * @prop {HDToPublic} toPublic - returns public key
  * @prop {Number} HARDENED_OFFSET - 0x80000000
  * @prop {HDVersions} MAINNET - 'xprv' & 'xpub'
  * @prop {HDVersions} TESTNET - 'tprv' & 'tpub'
@@ -35,6 +38,7 @@
  * @prop {HDHasher} ripemd160sum
  * @prop {HDHasher} sha256sum
  * @prop {HDHasher} sha512hmac
+ * @prop {HDBase64Url} bytesToBase64Url
  * @prop {HDKeyToKey} toPublicKey
  */
 
@@ -218,6 +222,23 @@ var DashHd = ("object" === typeof module && exports) || {};
     return new Uint8Array(sig);
   };
 
+  /** @type {HDBase64Url} */
+  Utils.bytesToBase64Url = function (bytes) {
+    let bins = [];
+
+    for (let i = 0; i < bytes.length; i += 1) {
+      let b = bytes[i];
+      let s = String.fromCodePoint(b);
+      bins.push(s);
+    }
+
+    let str = bins.join("");
+    let b64 = btoa(str);
+    let b64url = b64.replace(/\+/g, "-").replace(/\//g, "_").replace(/=/g, "");
+
+    return b64url;
+  };
+
   /** @type {HDSecureErase} */
   Utils.secureErase = function (buf) {
     if (!Crypto.getRandomValues) {
@@ -248,6 +269,8 @@ var DashHd = ("object" === typeof module && exports) || {};
   let XKEY_SIZE = 74;
   let XKEY_DEPTH = 4; // m/44'/5'/0'/<0>[/0]
 
+  DashHd._utils = Utils;
+
   // Bitcoin defaults hard-coded by default.
   // Use package `coininfo` for others.
   DashHd.MAINNET = { private: 0x0488ade4, public: 0x0488b21e };
@@ -651,6 +674,29 @@ var DashHd = ("object" === typeof module && exports) || {};
     return hdkey;
   };
 
+  DashHd.toId = async function (hdkey) {
+    let idBytes = await DashHd.toIdBytes(hdkey);
+    let id = Utils.bytesToBase64Url(idBytes);
+
+    return id;
+  };
+
+  DashHd.toIdBytes = async function (hdkey) {
+    let xpubBytes = await DashHd.toXPubBytes(hdkey);
+
+    let hashBuffer = await Crypto.subtle.digest("SHA-256", xpubBytes);
+    let idBuffer = hashBuffer.slice(0, 8);
+    let idBytes = new Uint8Array(idBuffer);
+
+    return idBytes;
+  };
+
+  DashHd.toPublic = function (_hdkey) {
+    let hdkey = Object.assign({}, _hdkey);
+    hdkey.privateKey = null;
+    return hdkey;
+  };
+
   DashHd.wipePrivateData = function (hdkey) {
     if (hdkey.privateKey) {
       Utils.secureErase(hdkey.privateKey);
@@ -659,6 +705,12 @@ var DashHd = ("object" === typeof module && exports) || {};
     return hdkey;
   };
 
+  DashHd.toPublic = function (_hdkey) {
+    let hdkey = Object.assign({}, _hdkey);
+    hdkey.privateKey = null;
+    return hdkey;
+  };
+
   /**
    * @param {Boolean} assertion
    * @param {String} message
@@ -828,6 +880,18 @@ if ("object" === typeof module) {
  * @returns {Promise<String>}
  */
 
+/**
+ * @callback HDToId
+ * @param {HDKey} hdkey
+ * @returns {Promise<String>}
+ */
+
+/**
+ * @callback HDToIdBytes
+ * @param {HDKey} hdkey
+ * @returns {Promise<Uint8Array>}
+ */
+
 /**
  * @callback HDToXKeyBytes
  * @param {HDKey} hdkey
@@ -871,6 +935,12 @@ if ("object" === typeof module) {
  * @returns {Promise<String>}
  */
 
+/**
+ * @callback HDBase64Url
+ * @param {Uint8Array} bytes
+ * @returns {String} - URL-Safe Base64 Encoding
+ */
+
 /**
  * @callback HDHasher
  * @param {Uint8Array} bytes
@@ -908,6 +978,12 @@ if ("object" === typeof module) {
  * @param {Uint8Array} buf
  */
 
+/**
+ * @callback HDToPublic
+ * @param {HDKey} hdkey
+ * @returns {HDKey}
+ */
+
 /**
  * @callback HDWipePrivates
  * @param {HDKey} hdkey

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dashhd",
-  "version": "3.1.0",
+  "version": "3.2.0",
   "description": "Manage HD Keys from HD Wallet Seed and Extended (xprv, xpub) Key Paths. Part of $DASH Tools.",
   "main": "dashhd.js",
   "browser": {