diff --git a/.github/workflows/test_e2e.yml b/.github/workflows/test_e2e.yml
index bdf979bf9..120fd0db3 100644
--- a/.github/workflows/test_e2e.yml
+++ b/.github/workflows/test_e2e.yml
@@ -35,7 +35,7 @@ jobs:
           cd database
           yarn && yarn dev_reset
           cd ../backend
-          yarn && yarn seed
+          yarn && yarn build && yarn seed
 
       - name: Boot up test system | docker-compose mailserver
         run: docker compose -f docker-compose.yml -f docker-compose.test.yml up --detach --no-deps mailserver
diff --git a/backend/src/graphql/resolver/CommunityResolver.test.ts b/backend/src/graphql/resolver/CommunityResolver.test.ts
index 8b5c05d5b..f9e6aa9ac 100644
--- a/backend/src/graphql/resolver/CommunityResolver.test.ts
+++ b/backend/src/graphql/resolver/CommunityResolver.test.ts
@@ -28,6 +28,8 @@ import { peterLustig } from '@/seeds/users/peter-lustig'
 
 import { getCommunityByUuid } from './util/communities'
 
+jest.mock('@/password/EncryptorUtils')
+
 // to do: We need a setup for the tests that closes the connection
 let mutate: ApolloServerTestClient['mutate'],
   query: ApolloServerTestClient['query'],
diff --git a/backend/src/graphql/resolver/ContributionLinkResolver.test.ts b/backend/src/graphql/resolver/ContributionLinkResolver.test.ts
index 23be529d3..3a3196c85 100644
--- a/backend/src/graphql/resolver/ContributionLinkResolver.test.ts
+++ b/backend/src/graphql/resolver/ContributionLinkResolver.test.ts
@@ -22,6 +22,8 @@ import { listContributionLinks } from '@/seeds/graphql/queries'
 import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
 import { peterLustig } from '@/seeds/users/peter-lustig'
 
+jest.mock('@/password/EncryptorUtils')
+
 let mutate: ApolloServerTestClient['mutate'],
   query: ApolloServerTestClient['query'],
   con: Connection
diff --git a/backend/src/graphql/resolver/ContributionMessageResolver.test.ts b/backend/src/graphql/resolver/ContributionMessageResolver.test.ts
index 88d79d5c6..a82f623cc 100644
--- a/backend/src/graphql/resolver/ContributionMessageResolver.test.ts
+++ b/backend/src/graphql/resolver/ContributionMessageResolver.test.ts
@@ -27,6 +27,7 @@ import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
 import { bobBaumeister } from '@/seeds/users/bob-baumeister'
 import { peterLustig } from '@/seeds/users/peter-lustig'
 
+jest.mock('@/password/EncryptorUtils')
 jest.mock('@/emails/sendEmailVariants', () => {
   const originalModule = jest.requireActual('@/emails/sendEmailVariants')
   return {
diff --git a/backend/src/graphql/resolver/ContributionResolver.test.ts b/backend/src/graphql/resolver/ContributionResolver.test.ts
index 9317b76e7..5c7a3e77d 100644
--- a/backend/src/graphql/resolver/ContributionResolver.test.ts
+++ b/backend/src/graphql/resolver/ContributionResolver.test.ts
@@ -59,6 +59,7 @@ import { stephenHawking } from '@/seeds/users/stephen-hawking'
 import { getFirstDayOfPreviousNMonth } from '@/util/utilities'
 
 jest.mock('@/emails/sendEmailVariants')
+jest.mock('@/password/EncryptorUtils')
 
 let mutate: ApolloServerTestClient['mutate'],
   query: ApolloServerTestClient['query'],
diff --git a/backend/src/graphql/resolver/KlicktippResolver.test.ts b/backend/src/graphql/resolver/KlicktippResolver.test.ts
index 2c819f070..06430c620 100644
--- a/backend/src/graphql/resolver/KlicktippResolver.test.ts
+++ b/backend/src/graphql/resolver/KlicktippResolver.test.ts
@@ -15,6 +15,8 @@ import { userFactory } from '@/seeds/factory/user'
 import { login, subscribeNewsletter, unsubscribeNewsletter } from '@/seeds/graphql/mutations'
 import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
 
+jest.mock('@/password/EncryptorUtils')
+
 let testEnv: any, mutate: any, con: any
 
 beforeAll(async () => {
diff --git a/backend/src/graphql/resolver/TransactionLinkResolver.test.ts b/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
index fe047b35a..bcea43416 100644
--- a/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
+++ b/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
@@ -38,6 +38,8 @@ import { TRANSACTIONS_LOCK } from '@/util/TRANSACTIONS_LOCK'
 
 import { transactionLinkCode } from './TransactionLinkResolver'
 
+jest.mock('@/password/EncryptorUtils')
+
 // mock semaphore to allow use fake timers
 jest.mock('@/util/TRANSACTIONS_LOCK')
 TRANSACTIONS_LOCK.acquire = jest.fn().mockResolvedValue(jest.fn())
diff --git a/backend/src/graphql/resolver/TransactionResolver.test.ts b/backend/src/graphql/resolver/TransactionResolver.test.ts
index 4bf5ab493..7cc6143e6 100644
--- a/backend/src/graphql/resolver/TransactionResolver.test.ts
+++ b/backend/src/graphql/resolver/TransactionResolver.test.ts
@@ -37,6 +37,8 @@ import { garrickOllivander } from '@/seeds/users/garrick-ollivander'
 import { peterLustig } from '@/seeds/users/peter-lustig'
 import { stephenHawking } from '@/seeds/users/stephen-hawking'
 
+jest.mock('@/password/EncryptorUtils')
+
 let mutate: ApolloServerTestClient['mutate'], con: Connection
 let query: ApolloServerTestClient['query']
 
diff --git a/backend/src/graphql/resolver/UserResolver.test.ts b/backend/src/graphql/resolver/UserResolver.test.ts
index b8e4a5750..6cbcf9830 100644
--- a/backend/src/graphql/resolver/UserResolver.test.ts
+++ b/backend/src/graphql/resolver/UserResolver.test.ts
@@ -74,6 +74,7 @@ import { objectValuesToArray } from '@/util/utilities'
 import { Location2Point } from './util/Location2Point'
 
 jest.mock('@/apis/humhub/HumHubClient')
+jest.mock('@/password/EncryptorUtils')
 
 jest.mock('@/emails/sendEmailVariants', () => {
   const originalModule = jest.requireActual('@/emails/sendEmailVariants')
diff --git a/backend/src/graphql/resolver/semaphore.test.ts b/backend/src/graphql/resolver/semaphore.test.ts
index ed58d55ec..f3dcce6f6 100644
--- a/backend/src/graphql/resolver/semaphore.test.ts
+++ b/backend/src/graphql/resolver/semaphore.test.ts
@@ -25,6 +25,8 @@ import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
 import { bobBaumeister } from '@/seeds/users/bob-baumeister'
 import { peterLustig } from '@/seeds/users/peter-lustig'
 
+jest.mock('@/password/EncryptorUtils')
+
 let mutate: ApolloServerTestClient['mutate'], con: Connection
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
diff --git a/backend/src/graphql/resolver/util/creations.test.ts b/backend/src/graphql/resolver/util/creations.test.ts
index 83d787dd9..8b59d0b14 100644
--- a/backend/src/graphql/resolver/util/creations.test.ts
+++ b/backend/src/graphql/resolver/util/creations.test.ts
@@ -12,6 +12,8 @@ import { peterLustig } from '@/seeds/users/peter-lustig'
 
 import { getOpenCreations, getUserCreation } from './creations'
 
+jest.mock('@/password/EncryptorUtils')
+
 let mutate: ApolloServerTestClient['mutate'], con: Connection
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
diff --git a/backend/src/graphql/resolver/util/findUserByIdentifiers.test.ts b/backend/src/graphql/resolver/util/findUserByIdentifiers.test.ts
index cfdbce8f2..1cdca8429 100644
--- a/backend/src/graphql/resolver/util/findUserByIdentifiers.test.ts
+++ b/backend/src/graphql/resolver/util/findUserByIdentifiers.test.ts
@@ -16,6 +16,8 @@ import { peterLustig } from '@/seeds/users/peter-lustig'
 
 import { findUserByIdentifier } from './findUserByIdentifier'
 
+jest.mock('@/password/EncryptorUtils')
+
 let con: Connection
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
diff --git a/backend/src/graphql/resolver/util/sendTransactionsToDltConnector.test.ts b/backend/src/graphql/resolver/util/sendTransactionsToDltConnector.test.ts
index 0d85a35af..064184a9d 100644
--- a/backend/src/graphql/resolver/util/sendTransactionsToDltConnector.test.ts
+++ b/backend/src/graphql/resolver/util/sendTransactionsToDltConnector.test.ts
@@ -32,6 +32,8 @@ import { raeuberHotzenplotz } from '@/seeds/users/raeuber-hotzenplotz'
 
 import { sendTransactionsToDltConnector } from './sendTransactionsToDltConnector'
 
+jest.mock('@/password/EncryptorUtils')
+
 /*
 // Mock the GraphQLClient
 jest.mock('graphql-request', () => {
diff --git a/backend/src/password/EncryptionWorker.ts b/backend/src/password/EncryptionWorker.ts
index 2299a1a9b..00129dc69 100644
--- a/backend/src/password/EncryptionWorker.ts
+++ b/backend/src/password/EncryptionWorker.ts
@@ -18,7 +18,7 @@ export const SecretKeyCryptographyCreateKey = (
   password: string,
   configLoginAppSecret: Buffer,
   configLoginServerKey: Buffer,
-): Buffer[] => {
+): Uint8Array[] => {
   const state = Buffer.alloc(crypto_hash_sha512_STATEBYTES)
   crypto_hash_sha512_init(state)
   crypto_hash_sha512_update(state, Buffer.from(salt))
@@ -42,7 +42,7 @@ export const SecretKeyCryptographyCreateKey = (
   const encryptionKeyHash = Buffer.alloc(crypto_shorthash_BYTES)
   crypto_shorthash(encryptionKeyHash, encryptionKey, configLoginServerKey)
 
-  return [encryptionKeyHash, encryptionKey]
+  return [new Uint8Array(encryptionKeyHash), new Uint8Array(encryptionKey)]
 }
 
 worker({
diff --git a/backend/src/password/EncryptorUtils.ts b/backend/src/password/EncryptorUtils.ts
index 74b9f91d0..7086547a2 100644
--- a/backend/src/password/EncryptorUtils.ts
+++ b/backend/src/password/EncryptorUtils.ts
@@ -21,7 +21,7 @@ const configLoginServerKey = Buffer.from(CONFIG.LOGIN_SERVER_KEY, 'hex')
 
 // TODO: put maxQueueSize into config
 const encryptionWorkerPool = pool(
-  path.join(__dirname, '..', '..', 'build', 'src', 'password', '/EncryptionWorker.js'),
+  path.join(__dirname, '..', '..', 'build', 'src', 'password', '/EncryptionWorker.ts'),
   {
     maxQueueSize: 30 * cpus().length,
   },
diff --git a/backend/src/util/klicktipp.test.ts b/backend/src/util/klicktipp.test.ts
index 6639a0aa4..a88e8f21a 100644
--- a/backend/src/util/klicktipp.test.ts
+++ b/backend/src/util/klicktipp.test.ts
@@ -19,6 +19,7 @@ import { peterLustig } from '@/seeds/users/peter-lustig'
 import { exportEventDataToKlickTipp } from './klicktipp'
 
 jest.mock('@/apis/KlicktippController')
+jest.mock('@/password/EncryptorUtils')
 
 let mutate: ApolloServerTestClient['mutate'], con: Connection
 let testEnv: {