diff --git a/README.md b/README.md
index aba508b..317cfdf 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,7 @@ const decoded = base64Decode(encoded); // Restored.
 ```ts
 const file = await Deno.readFile("/path/to/binary.bin");
 
+const random = await cryptoRandom(16); // random byte array.
 const hash = await cryptoHash(true, file); // byte array of SHA2 512 bits hash value.
 const keyEcdh = await cryptoGenerateKey(true); // public/private key pair for ECDH, each in byte array.
 const keyEcdsa = await cryptoGenerateKey(false); // public/private key pair for ECDSA, each in byte array.
@@ -120,6 +121,19 @@ The actual binary structure looks like this:
 
 This is for one file and repeats for the number of files.
 
+# Browser Compatible
+Some methods and classes in this module don't use `globalThis.Deno` internally and are browser compatible.
+
+I have prepared browser compatible code only export as [mod.compatible.ts](./mod.compatible.ts).
+
+By bundling this, you can easily create universal utility scripts.
+
+```sh
+deno bundle https://deno.land/x/simple_utility@(version)/mod.compatible.ts > ./simple_utility.esm.js
+```
+
+This section may eventually be automated with GitHub Actions, in which case the bundled scripts will be merged into GitHub Releases, making this step unnecessary.
+
 # Tips
 This section is not directly related to this module, but provides a few line snippets to help you implement your application.
 
@@ -138,18 +152,5 @@ const {default: data} = await import("./data.json", {assert: {type: "json"}});
 </details>
 </p>
 
-# Browser Compatible
-Some methods and classes in this module don't use `globalThis.Deno` internally and are browser compatible.
-
-I have prepared browser compatible code only export as [mod.compatible.ts](./mod.compatible.ts).
-
-By bundling this, you can easily create universal utility scripts.
-
-```sh
-deno bundle https://deno.land/x/simple_utility@(version)/mod.compatible.ts > ./simple_utility.esm.js
-```
-
-This section may eventually be automated with GitHub Actions, in which case the bundled scripts will be merged into GitHub Releases, making this step unnecessary.
-
 # API
 See [Deno Document](https://deno.land/x/simple_utility/mod.ts) for details.
\ No newline at end of file
diff --git a/src/core.d.ts b/src/core.d.ts
index 7ca18c6..9f1cce1 100644
--- a/src/core.d.ts
+++ b/src/core.d.ts
@@ -6,4 +6,9 @@ export type SyncFunction<T extends unknown = void> = () => T;
 /**
 * Function returning arbitrary async types.
 */
-export type AsyncFunction<T extends unknown = void> = SyncFunction<Promise<T>>;
\ No newline at end of file
+export type AsyncFunction<T extends unknown = void> = SyncFunction<Promise<T>>;
+
+/**
+* The file name and byte array pairs that make up the basic file.
+*/
+export type FileInit = [string, Uint8Array];
\ No newline at end of file
diff --git a/src/crypto.ts b/src/crypto.ts
index 33a058c..a57f536 100644
--- a/src/crypto.ts
+++ b/src/crypto.ts
@@ -37,6 +37,15 @@ async function deriveSecretKey(kp:PortableCryptoKeyPair){
     return await crypto.subtle.deriveKey(dh, privateKey, aes, false, ["encrypt", "decrypt"]);
 }
 
+/**
+* Returns random byte array with the specified number of bytes.
+* @param size number of bytes.
+* @return random byte array.
+*/
+export async function cryptoRandom(size:number){
+    return await new Promise<Uint8Array>(done => done(crypto.getRandomValues(new Uint8Array(size))));
+}
+
 /**
 * Derive SHA2 hash value from byte array.
 * @param is512 Use the hash length 512 bits if `true`, 256 bits if `false`.
@@ -81,7 +90,7 @@ export async function cryptoEncrypt(kp:PortableCryptoKeyPair, data:Uint8Array){
     const gcm:AesGcmParams = {
         name: "AES-GCM",
         tagLength: sizeTag * 8,
-        iv: crypto.getRandomValues(new Uint8Array(sizeIv))
+        iv: await cryptoRandom(sizeIv)
     };
 
     const secretKey = await deriveSecretKey(kp);
@@ -107,9 +116,9 @@ export async function cryptoDecrypt(kp:PortableCryptoKeyPair, data:Uint8Array){
         iv: data.subarray(0, sizeIv)
     };
 
-    const commonKey = await deriveSecretKey(kp);
+    const secretKey = await deriveSecretKey(kp);
 
-    return new Uint8Array(await crypto.subtle.decrypt(gcm, commonKey, data.subarray(sizeIv)));
+    return new Uint8Array(await crypto.subtle.decrypt(gcm, secretKey, data.subarray(sizeIv)));
 }
 
 /**
diff --git a/src/minipack.ts b/src/minipack.ts
index 7d55763..811f18f 100644
--- a/src/minipack.ts
+++ b/src/minipack.ts
@@ -1,11 +1,7 @@
+import {type FileInit} from "./core.d.ts";
 import {cryptoHash} from "./crypto.ts";
 import {ucEncode, ucDecode, hexEncode} from "./text.ts";
 
-/**
-* The file name and byte array pairs that make up the basic file.
-*/
-export type FileInit = [string, Uint8Array];
-
 const sizeHash = 32;
 const sizeName = 1;
 const sizeBody = 4;
diff --git a/test/crypto.test.ts b/test/crypto.test.ts
index 20bba15..2b86e83 100644
--- a/test/crypto.test.ts
+++ b/test/crypto.test.ts
@@ -1,5 +1,5 @@
 import {assertEquals} from "../deps.test.ts";
-import {cryptoHash, cryptoGenerateKey, cryptoEncrypt, cryptoDecrypt, cryptoSign, cryptoVerify} from "../src/crypto.ts";
+import {cryptoRandom, cryptoHash, cryptoGenerateKey, cryptoEncrypt, cryptoDecrypt, cryptoSign, cryptoVerify} from "../src/crypto.ts";
 
 const sample = new Uint8Array([0x02, 0xF2, 0x5D, 0x1F, 0x1C, 0x34, 0xB9, 0x2F]);
 
@@ -14,6 +14,15 @@ const hashResult = new Uint8Array([
     0x0D, 0xE6, 0x31, 0xDA, 0x4B, 0xBD, 0xD4, 0x58
 ]);
 
+Deno.test({
+    name: "Crypto: Random",
+    async fn(){
+        const random = await cryptoRandom(16);
+
+        assertEquals(random.byteLength, 16);
+    }
+});
+
 Deno.test({
     name: "Crypto: Hash",
     async fn(){