diff --git a/lib/jws.js b/lib/jws.js
index 159016d..698ef28 100644
--- a/lib/jws.js
+++ b/lib/jws.js
@@ -1,5 +1,5 @@
 import { decodeBase64UrlAsArray, decodeBase64UrlAsString, encodeBase64UrlAsString } from '../utils/base64.js';
-import { octetFromUtf8 } from '../utils/utf8.js';
+import { uint8ArrayFromUtf8 } from '../utils/utf8.js';
 
 import KeyStore from './KeyStore.js';
 import { decodeProtectedHeader, encodePayload, encodeProtectedHeader } from './jose.js';
@@ -177,7 +177,7 @@ export async function validateSignature(encodedPayload, signatureObject, jwk) {
     const verified = await KeyStore.default.verify(
       jwk,
       decodeBase64UrlAsArray(signature),
-      Uint8Array.from(octetFromUtf8(signingInput)),
+      uint8ArrayFromUtf8(signingInput),
     );
     if (verified) return;
   } catch (e) { console.error(e); }
diff --git a/test/lib/jws.js b/test/lib/jws.js
index b8b05b7..805203a 100644
--- a/test/lib/jws.js
+++ b/test/lib/jws.js
@@ -1,7 +1,7 @@
 import { createES256JWK, createES512JWK, createHS256JWK, createRS256JWK } from '../../lib/jwa.js';
 import { decodeJSON, decodeJSONUnsafe, decodeString, decodeStringUnsafe, decodeUint8Array, decodeUint8ArrayUnsafe, signCompact, signObject, validate } from '../../lib/jws.js';
 import { decodeBase64AsString, decodeBase64UrlAsArray, encodeBase64UrlAsString } from '../../utils/base64.js';
-import { octetFromUtf8 } from '../../utils/utf8.js';
+import { uint8ArrayFromUtf8 } from '../../utils/utf8.js';
 import test from '../tester.js';
 
 const RFC7515_APPENDIX_A_JWS = 'eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk';
@@ -344,7 +344,7 @@ test('CVE-2015-9235 - Replicate setup', async (t) => {
   const header = { alg: 'HS256', typ: 'JWT' };
   const payload = { loggedInAs: 'admin', iat: 1_422_779_638 };
   const key = 'secretkey';
-  const hmacKey = new Uint8Array(octetFromUtf8(key));
+  const hmacKey = uint8ArrayFromUtf8(key);
   const symmetricalJWK = createHS256JWK({ k: hmacKey });
   const symmetricalJWS = await signCompact({
     protected: header,
@@ -360,7 +360,7 @@ test('CVE-2015-9235 - Validation should fail if token specifies alg:none though
   const header = { alg: 'none', typ: 'JWT' };
   const payload = { loggedInAs: 'admin', iat: 1_422_779_638 };
   const key = 'secretkey';
-  const hmacKey = new Uint8Array(octetFromUtf8(key));
+  const hmacKey = uint8ArrayFromUtf8(key);
   const symmetricalJWK = createHS256JWK({ k: hmacKey });
 
   // Will not allow conflict when signing
diff --git a/utils/asn1/encoder.js b/utils/asn1/encoder.js
index ffc0e43..a89b4ac 100644
--- a/utils/asn1/encoder.js
+++ b/utils/asn1/encoder.js
@@ -1,7 +1,7 @@
 /* eslint-disable no-bitwise */
 
 import { decodeBase64AsArray } from '../base64.js';
-import { octetFromUtf8 } from '../utf8.js';
+import { uint8ArrayFromUtf8 } from '../utf8.js';
 
 // https://letsencrypt.org/docs/a-warm-welcome-to-asn1-and-der/
 
@@ -178,17 +178,16 @@ export function encodeDER(tag, entry) {
  */
 export function encodeUTF8String(utf8String) {
   // ASCII to Hex is the same as UTF8 to HEX (no check)
-  const entry = [...octetFromUtf8(utf8String)];
-  return encodeDER(ASN_TAG.UTF8_STRING, entry);
+  return encodeDER(ASN_TAG.UTF8_STRING, uint8ArrayFromUtf8(utf8String));
 }
 
 /**
  * @param {string} ia5String
- * @return {number[]}
+ * @return {ArrayLike<number>&Iterable<number>}
  */
 export function writeIA5String(ia5String) {
   // First 128 characters of ASCII (no check)
-  return [...octetFromUtf8(ia5String)];
+  return uint8ArrayFromUtf8(ia5String);
 }
 
 /**
@@ -326,8 +325,7 @@ export function encodeBitString(data, length = data.length * 8) {
 export function encodePrintableString(printableString) {
   // ASCII to Hex is the same as UTF8 to HEX
   // No checks here
-  const entry = [...octetFromUtf8(printableString)];
-  return encodeDER(ASN_TAG.PRINTABLE_STRING, entry);
+  return encodeDER(ASN_TAG.PRINTABLE_STRING, uint8ArrayFromUtf8(printableString));
 }
 
 /**
diff --git a/utils/base64.js b/utils/base64.js
index a2b9153..5190411 100644
--- a/utils/base64.js
+++ b/utils/base64.js
@@ -1,7 +1,7 @@
 /* eslint-disable no-bitwise */
 // https://datatracker.ietf.org/doc/html/rfc4648#section-4
 
-import { octetFromUtf8 } from './utf8.js';
+import { uint8ArrayFromUtf8 } from './utf8.js';
 
 const BASE64_CHAR_62 = '+';
 const BASE64_CHAR_63 = '/';
@@ -42,7 +42,7 @@ const BIT_MASK_8 = BIT_MASKS.get(8);
  */
 function toIterableUint8(source) {
   if (typeof source === 'string') {
-    return octetFromUtf8(source);
+    return uint8ArrayFromUtf8(source);
   }
   if (source instanceof Uint8Array) {
     return source;
diff --git a/utils/crypto.js b/utils/crypto.js
index 352f814..8171a52 100644
--- a/utils/crypto.js
+++ b/utils/crypto.js
@@ -3,7 +3,7 @@
 
 import { parseAlgorithmIdentifier } from '../lib/jwa.js';
 
-import { octetFromUtf8 } from './utf8.js';
+import { uint8ArrayFromUtf8 } from './utf8.js';
 
 /** @type {Crypto} */
 // eslint-disable-next-line unicorn/no-await-expression-member
@@ -31,7 +31,7 @@ export async function importJWK(jwk, algorithmIdentifier) {
  * @return {Promise<ArrayBuffer>}
  */
 export async function sign(algorithmIdentifier, key, data) {
-  const binary = typeof data === 'string' ? Uint8Array.from(octetFromUtf8(data)) : data;
+  const binary = typeof data === 'string' ? uint8ArrayFromUtf8(data) : data;
   return await crypto.subtle.sign(algorithmIdentifier, key, binary);
 }
 
@@ -72,6 +72,6 @@ export async function decrypt(algorithmIdentifier, key, data) {
  * @return {Promise<ArrayBuffer>}
  */
 export async function digest(algorithm, data) {
-  const binary = typeof data === 'string' ? Uint8Array.from(octetFromUtf8(data)) : data;
+  const binary = typeof data === 'string' ? uint8ArrayFromUtf8(data) : data;
   return await crypto.subtle.digest(algorithm, binary);
 }
diff --git a/utils/utf8.js b/utils/utf8.js
index 72e71f6..ec35510 100644
--- a/utils/utf8.js
+++ b/utils/utf8.js
@@ -43,3 +43,15 @@ export function* octetFromUtf8(utf8) {
     }
   }
 }
+
+/** @type {TextEncoder} */
+let textEncoder;
+
+/**
+ * @param {string} utf8
+ * @return {Uint8Array}
+ */
+export function uint8ArrayFromUtf8(utf8) {
+  textEncoder ??= new TextEncoder();
+  return textEncoder.encode(utf8);
+}