diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..5687371
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,21 @@
+type NativeCrypto = Crypto;
+type NativeSubtleCrypto = SubtleCrypto;
+type NativeCryptoKey = CryptoKey;
+
+declare namespace WebCrypto {
+
+  class Crypto implements NativeCrypto {
+    public subtle: SubtleCrypto;
+    public getRandomValues<T extends Int8Array | Int16Array | Int32Array | Uint8Array | Uint16Array | Uint32Array | Uint8ClampedArray | Float32Array | Float64Array | DataView | null>(array: T): T;
+  }
+
+  class CryptoKey implements NativeCryptoKey {
+    public algorithm: KeyAlgorithm;
+    public extractable: boolean;
+    public type: KeyType;
+    public usages: KeyUsage[];
+  }
+
+}
+
+export = WebCrypto;