package: crypto-browserify must be specified until browserify catches up

package.json

@@ -68,10 +68,14 @@
     "test": "npm run-script unit",
     "unit": "istanbul test mocha -- --reporter list test/*.js"
   },
+  "browser": {
+    "crypto": "crypto-browserify"
+  },
   "dependencies": {
     "bigi": "1.1.0",
     "bs58": "1.2.1",
     "bs58check": "1.0.1",
+    "crypto-browserify": "3.2.0",
     "ecurve": "1.0.0"
   }
 }