diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index ce9b0dcd6b..5bc9784925 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -414,7 +414,7 @@ passwordMatched: "一致しました"
 passwordNotMatched: "一致していません"
 signinWith: "{x}でログイン"
 signinFailed: "ログインできませんでした。ユーザー名とパスワードを確認してください。"
-tapSecurityKey: "セキュリティーキーにタッチ"
+tapSecurityKey: "セキュリティキーにタッチ"
 or: "もしくは"
 uiLanguage: "UIの表示言語"
 groupInvited: "グループに招待されました"
diff --git a/src/client/components/signin.vue b/src/client/components/signin.vue
index b84b89a5c7..dc73ad8a0f 100755
--- a/src/client/components/signin.vue
+++ b/src/client/components/signin.vue
@@ -51,7 +51,7 @@ import MkButton from './ui/button.vue';
 import MkInput from './ui/input.vue';
 import i18n from '../i18n';
 import { apiUrl, host } from '../config';
-import { hexifyAB } from '../scripts/2fa';
+import { byteify, hexify } from '../scripts/2fa';
 
 export default Vue.extend({
 	i18n,
@@ -121,14 +121,9 @@ export default Vue.extend({
 			this.queryingKey = true;
 			return navigator.credentials.get({
 				publicKey: {
-					challenge: Buffer.from(
-						this.challengeData.challenge
-							.replace(/\-/g, '+')
-							.replace(/_/g, '/'),
-							'base64'
-					),
+					challenge: byteify(this.challengeData.challenge, 'base64'),
 					allowCredentials: this.challengeData.securityKeys.map(key => ({
-						id: Buffer.from(key.id, 'hex'),
+						id: byteify(key.id, 'hex'),
 						type: 'public-key',
 						transports: ['usb', 'nfc', 'ble', 'internal']
 					})),
@@ -143,9 +138,9 @@ export default Vue.extend({
 				return this.$root.api('signin', {
 					username: this.username,
 					password: this.password,
-					signature: hexifyAB(credential.response.signature),
-					authenticatorData: hexifyAB(credential.response.authenticatorData),
-					clientDataJSON: hexifyAB(credential.response.clientDataJSON),
+					signature: hexify(credential.response.signature),
+					authenticatorData: hexify(credential.response.authenticatorData),
+					clientDataJSON: hexify(credential.response.clientDataJSON),
 					credentialId: credential.id,
 					challengeId: this.challengeData.challengeId
 				});
diff --git a/src/client/pages/my-settings/2fa.vue b/src/client/pages/my-settings/2fa.vue
index 1d1e111dac..6ceca21fe6 100644
--- a/src/client/pages/my-settings/2fa.vue
+++ b/src/client/pages/my-settings/2fa.vue
@@ -22,12 +22,12 @@
 
 				<mk-switch v-model="usePasswordLessLogin" @change="updatePasswordLessLogin" v-if="$store.state.i.securityKeysList.length > 0">{{ $t('passwordLessLogin') }}</mk-switch>
 
-				<mk-info warn v-if="registration && registration.error">{{ $t('something-went-wrong') }} {{ registration.error }}</mk-info>
+				<mk-info warn v-if="registration && registration.error">{{ $t('error') }} {{ registration.error }}</mk-info>
 				<mk-button v-if="!registration || registration.error" @click="addSecurityKey">{{ $t('_2fa.registerKey') }}</mk-button>
 
 				<ol v-if="registration && !registration.error">
 					<li v-if="registration.stage >= 0">
-						{{ $t('activate-key') }}
+						{{ $t('tapSecurityKey') }}
 						<fa icon="spinner" pulse fixed-width v-if="registration.saving && registration.stage == 0" />
 					</li>
 					<li v-if="registration.stage >= 1">
@@ -67,16 +67,12 @@ import Vue from 'vue';
 import { faLock } from '@fortawesome/free-solid-svg-icons';
 import i18n from '../../i18n';
 import { hostname } from '../../config';
-import { hexifyAB } from '../../scripts/2fa';
+import { byteify, hexify, stringify } from '../../scripts/2fa';
 import MkButton from '../../components/ui/button.vue';
 import MkInfo from '../../components/ui/info.vue';
 import MkInput from '../../components/ui/input.vue';
 import MkSwitch from '../../components/ui/switch.vue';
 
-function stringifyAB(buffer) {
-	return String.fromCharCode.apply(null, new Uint8Array(buffer));
-}
-
 export default Vue.extend({
 	i18n,
 	components: {
@@ -157,8 +153,8 @@ export default Vue.extend({
 				name: this.keyName,
 				challengeId: this.registration.challengeId,
 				// we convert each 16 bits to a string to serialise
-				clientDataJSON: stringifyAB(this.registration.credential.response.clientDataJSON),
-				attestationObject: hexifyAB(this.registration.credential.response.attestationObject)
+				clientDataJSON: stringify(this.registration.credential.response.clientDataJSON),
+				attestationObject: hexify(this.registration.credential.response.attestationObject)
 			}).then(key => {
 				this.registration = null;
 				key.lastUsed = new Date();
@@ -208,18 +204,13 @@ export default Vue.extend({
 						challengeId: registration.challengeId,
 						stage: 0,
 						publicKeyOptions: {
-							challenge: Uint8Array.from(
-								atob(registration.challenge
-									.replace(/\-/g, '+')
-									.replace(/_/g, '/')),
-								x => x.charCodeAt(0),
-							),
+							challenge: byteify(registration.challenge, 'base64'),
 							rp: {
 								id: hostname,
 								name: 'Misskey'
 							},
 							user: {
-								id: Uint8Array.from(this.$store.state.i.id, c => c.charCodeAt(0)),
+								id: byteify(this.$store.state.i.id, 'ascii'),
 								name: this.$store.state.i.username,
 								displayName: this.$store.state.i.name,
 							},
diff --git a/src/client/scripts/2fa.ts b/src/client/scripts/2fa.ts
index e431361aac..00363cffa6 100644
--- a/src/client/scripts/2fa.ts
+++ b/src/client/scripts/2fa.ts
@@ -1,5 +1,33 @@
-export function hexifyAB(buffer) {
-	return Array.from(new Uint8Array(buffer))
-		.map(item => item.toString(16).padStart(2, '0'))
-		.join('');
+export function byteify(data: string, encoding: 'ascii' | 'base64' | 'hex') {
+	switch (encoding) {
+		case 'ascii':
+			return Uint8Array.from(data, c => c.charCodeAt(0));
+		case 'base64':
+			return Uint8Array.from(
+				atob(
+					data
+						.replace(/-/g, '+')
+						.replace(/_/g, '/')
+				),
+				c => c.charCodeAt(0)
+			);
+		case 'hex':
+			return new Uint8Array(
+				data
+					.match(/.{1,2}/g)
+					.map(byte => parseInt(byte, 16))
+			);
+	}
+}
+
+export function hexify(buffer: ArrayBuffer) {
+	return Array.from(new Uint8Array(buffer))
+		.reduce(
+			(str, byte) => str + byte.toString(16).padStart(2, '0'),
+			''
+		);
+}
+
+export function stringify(buffer: ArrayBuffer) {
+	return String.fromCharCode(... new Uint8Array(buffer));
 }