diff --git a/src/herumi/context.ts b/src/herumi/context.ts
index 5a56065..b23997c 100644
--- a/src/herumi/context.ts
+++ b/src/herumi/context.ts
@@ -6,15 +6,21 @@ type Bls = typeof bls;
 let blsGlobal: Bls | null = null;
 let blsGlobalPromise: Promise<void> | null = null;
 
+// Patch to fix multiVerify() calls on a browser with polyfilled NodeJS crypto
+declare global {
+  interface Window {
+    msCrypto: typeof window["crypto"];
+  }
+}
+
 export async function setupBls(): Promise<void> {
   if (!blsGlobal) {
     await bls.init(bls.BLS12_381);
 
     // Patch to fix multiVerify() calls on a browser with polyfilled NodeJS crypto
-    // @ts-ignore
     if (typeof window === "object") {
-      // @ts-ignore
       const crypto = window.crypto || window.msCrypto;
+      // getRandomValues is not typed in `bls-eth-wasm` because it's not meant to be exposed
       // @ts-ignore
       bls.getRandomValues = (x) => crypto.getRandomValues(x);
     }
diff --git a/tsconfig.json b/tsconfig.json
index a15932d..5b70769 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -4,7 +4,7 @@
     "target": "esnext",
     "module": "commonjs",
     "pretty": true,
-    "lib": ["esnext.bigint"],
+    "lib": ["esnext.bigint", "DOM"],
     "typeRoots": ["./node_modules/@types"],
     "declaration": true,
     "strict": true,