diff --git a/backend/src/graphql/resolver/UserResolver.test.ts b/backend/src/graphql/resolver/UserResolver.test.ts
index 2c74a7b8c..58b6b33c4 100644
--- a/backend/src/graphql/resolver/UserResolver.test.ts
+++ b/backend/src/graphql/resolver/UserResolver.test.ts
@@ -97,6 +97,8 @@ jest.mock('@/apis/KlicktippController', () => {
   }
 })
 
+CONFIG.EMAIL_CODE_REQUEST_TIME = 10
+
 let admin: User
 let user: User
 let mutate: ApolloServerTestClient['mutate'],
@@ -1548,11 +1550,9 @@ describe('UserResolver', () => {
 
         expect(bibi).toEqual(
           expect.objectContaining({
-            password: Buffer.from(
-              (await SecretKeyCryptographyCreateKey(bibi.gradidoID.toString(), 'Aa12345_'))[0],
-            )
-              .readBigUInt64LE()
-              .toString(),
+            password: (
+              await SecretKeyCryptographyCreateKey(bibi.gradidoID.toString(), 'Aa12345_')
+            ).toString(),
             passwordEncryptionType: PasswordEncryptionType.GRADIDO_ID,
           }),
         )
@@ -1574,9 +1574,7 @@ describe('UserResolver', () => {
         })
         bibi = usercontact.user
         bibi.passwordEncryptionType = PasswordEncryptionType.EMAIL
-        bibi.password = Buffer.from(
-          (await SecretKeyCryptographyCreateKey('bibi@bloxberg.de', 'Aa12345_'))[0],
-        ).readBigUInt64LE()
+        bibi.password = await SecretKeyCryptographyCreateKey('bibi@bloxberg.de', 'Aa12345_')
 
         await bibi.save()
       })
@@ -1593,11 +1591,9 @@ describe('UserResolver', () => {
         expect(bibi).toEqual(
           expect.objectContaining({
             firstName: 'Bibi',
-            password: Buffer.from(
-              (await SecretKeyCryptographyCreateKey(bibi.gradidoID.toString(), 'Aa12345_'))[0],
-            )
-              .readBigUInt64LE()
-              .toString(),
+            password: (
+              await SecretKeyCryptographyCreateKey(bibi.gradidoID.toString(), 'Aa12345_')
+            ).toString(),
             passwordEncryptionType: PasswordEncryptionType.GRADIDO_ID,
           }),
         )
diff --git a/backend/src/password/EncryptionWorker.ts b/backend/src/password/EncryptionWorker.ts
index 506a42c1e..f14d5d1ff 100644
--- a/backend/src/password/EncryptionWorker.ts
+++ b/backend/src/password/EncryptionWorker.ts
@@ -20,7 +20,7 @@ export const SecretKeyCryptographyCreateKey = (
   password: string,
   configLoginAppSecret: Buffer,
   configLoginServerKey: Buffer,
-): Uint8Array[] => {
+): bigint => {
   const state = Buffer.alloc(crypto_hash_sha512_STATEBYTES)
   crypto_hash_sha512_init(state)
   crypto_hash_sha512_update(state, Buffer.from(salt))
@@ -43,8 +43,7 @@ export const SecretKeyCryptographyCreateKey = (
 
   const encryptionKeyHash = Buffer.alloc(crypto_shorthash_BYTES)
   crypto_shorthash(encryptionKeyHash, encryptionKey, configLoginServerKey)
-
-  return [new Uint8Array(encryptionKeyHash), new Uint8Array(encryptionKey)]
+  return encryptionKeyHash.readBigUInt64LE()
 }
 
 if (CONFIG.USE_CRYPTO_WORKER) {
diff --git a/backend/src/password/EncryptorUtils.ts b/backend/src/password/EncryptorUtils.ts
index 1f8b706a2..27432d1a3 100644
--- a/backend/src/password/EncryptorUtils.ts
+++ b/backend/src/password/EncryptorUtils.ts
@@ -46,7 +46,7 @@ export const isValidPassword = (password: string): boolean => {
 export const SecretKeyCryptographyCreateKey = async (
   salt: string,
   password: string,
-): Promise<Uint8Array[]> => {
+): Promise<bigint> => {
   try {
     logger.trace('call worker for: SecretKeyCryptographyCreateKey')
     if (configLoginServerKey.length !== crypto_shorthash_KEYBYTES) {
@@ -56,14 +56,14 @@ export const SecretKeyCryptographyCreateKey = async (
         crypto_shorthash_KEYBYTES,
       )
     }
-    let result: Promise<Uint8Array[]>
+    let result: Promise<bigint>
     if (encryptionWorkerPool) {
       result = (await encryptionWorkerPool.exec('SecretKeyCryptographyCreateKey', [
         salt,
         password,
         configLoginAppSecret,
         configLoginServerKey,
-      ])) as Promise<Uint8Array[]>
+      ])) as Promise<bigint>
     } else {
       result = Promise.resolve(
         SecretKeyCryptographyCreateKeySync(
diff --git a/backend/src/password/PasswordEncryptor.ts b/backend/src/password/PasswordEncryptor.ts
index 1ee0a68a8..a97c29e7f 100644
--- a/backend/src/password/PasswordEncryptor.ts
+++ b/backend/src/password/PasswordEncryptor.ts
@@ -5,9 +5,7 @@ import { getUserCryptographicSalt, SecretKeyCryptographyCreateKey } from './Encr
 
 export const encryptPassword = async (dbUser: User, password: string): Promise<bigint> => {
   const salt = getUserCryptographicSalt(dbUser)
-  const keyBuffer: Uint8Array[] = await SecretKeyCryptographyCreateKey(salt, password) // returns Uint8Array[short hash, long hash]
-  const passwordHash = Buffer.from(keyBuffer[0]).readBigUInt64LE()
-  return passwordHash
+  return SecretKeyCryptographyCreateKey(salt, password)
 }
 
 export const verifyPassword = async (dbUser: User, password: string): Promise<boolean> => {
diff --git a/backend/src/password/__mocks__/EncryptorUtils.ts b/backend/src/password/__mocks__/EncryptorUtils.ts
index b406f1b1c..fcd3ff601 100644
--- a/backend/src/password/__mocks__/EncryptorUtils.ts
+++ b/backend/src/password/__mocks__/EncryptorUtils.ts
@@ -29,7 +29,7 @@ const SecretKeyCryptographyCreateKeyMock = (
   password: string,
   configLoginAppSecret: Buffer,
   configLoginServerKey: Buffer,
-): Uint8Array[] => {
+): bigint => {
   const state = Buffer.alloc(crypto_hash_sha512_STATEBYTES)
   crypto_hash_sha512_init(state)
   crypto_hash_sha512_update(state, Buffer.from(salt))
@@ -53,7 +53,7 @@ const SecretKeyCryptographyCreateKeyMock = (
   const encryptionKeyHash = Buffer.alloc(crypto_shorthash_BYTES)
   crypto_shorthash(encryptionKeyHash, encryptionKey, configLoginServerKey)
 
-  return [new Uint8Array(encryptionKeyHash), new Uint8Array(encryptionKey)]
+  return encryptionKeyHash.readBigUInt64LE()
 }
 
 const configLoginAppSecret = Buffer.from(CONFIG.LOGIN_APP_SECRET, 'hex')
@@ -72,7 +72,7 @@ export const isValidPassword = (password: string): boolean => {
 export const SecretKeyCryptographyCreateKey = async (
   salt: string,
   password: string,
-): Promise<Uint8Array[]> => {
+): Promise<bigint> => {
   try {
     logger.trace('call worker for: SecretKeyCryptographyCreateKey')
     if (configLoginServerKey.length !== crypto_shorthash_KEYBYTES) {