add shim for crypto module for older node versions

package.json

@@ -23,7 +23,7 @@
     "clean:bundle": "rimraf bundles",
     "clean": "npm run clean:dist && npm run clean:package && npm  run clean:bundle",
     "prepublishOnly": "npm run clean && npm run build",
-    "test": "mocha test/*.ts && echo \"NOW RUN => 'npm run test:web' <= \" ",
+    "test": "mocha --file test/shims.ts test/*.ts && echo \"NOW RUN => 'npm run test:web' <= \" ",
     "test:web": "npm run bundle:web && webpack --config-name web-tests && opener test/web/web.html",
     "prettier:check": "prettier --check \"src/**/*.ts\" \"test/**/*.ts\"",
     "prettier:write": "prettier --write \"src/**/*.ts\" \"test/**/*.ts\"",

test/keys.ts

@@ -1,4 +1,4 @@
-import { readFileSync, writeFileSync } from "fs";
+import { readFileSync } from "fs";
 import * as chai from "chai";
 
 import { EllipticCurvePrivateKey, EllipticCurvePublicKey, SECP256k1PrivateKey, SECP256k1PublicKey } from "../src/common/lib/crypto/keys";

test/shims.ts

@@ -0,0 +1,9 @@
+(function () {
+    if (!globalThis.crypto) {
+      try {
+        globalThis.crypto = require('crypto');
+      } catch (e) {
+        console.error('Failed to load crypto module in Node.js:', e);
+      }
+    }
+})();