diff --git a/backend/src/graphql/directive/isAuthorized.ts b/backend/src/graphql/directive/isAuthorized.ts
index 079e8e88c..6245ef8ba 100644
--- a/backend/src/graphql/directive/isAuthorized.ts
+++ b/backend/src/graphql/directive/isAuthorized.ts
@@ -10,7 +10,7 @@ const isAuthorized: AuthChecker<any> = async (
 ) => {
   if (context.token) {
     const decoded = decode(context.token)
-    context.pubKey = decoded.pubKey
+    context.pubKey = Buffer.from(decoded.pubKey).toString('hex')
     context.setHeaders.push({ key: 'token', value: encode(decoded.pubKey) })
     return true
   }
diff --git a/backend/src/graphql/resolver/BalanceResolver.ts b/backend/src/graphql/resolver/BalanceResolver.ts
index 902e50b8b..e067b4d68 100644
--- a/backend/src/graphql/resolver/BalanceResolver.ts
+++ b/backend/src/graphql/resolver/BalanceResolver.ts
@@ -18,8 +18,7 @@ export class BalanceResolver {
     const balanceRepository = getCustomRepository(BalanceRepository)
     const userRepository = getCustomRepository(UserRepository)
 
-    const pubKeyString = Buffer.from(context.pubKey).toString('hex')
-    const userEntity = await userRepository.findByPubkeyHex(pubKeyString)
+    const userEntity = await userRepository.findByPubkeyHex(context.pubKey)
     const balanceEntity = await balanceRepository.findByUser(userEntity.id)
     const now = new Date()
 
diff --git a/backend/src/graphql/resolver/GdtResolver.ts b/backend/src/graphql/resolver/GdtResolver.ts
index ba10d45bf..b4f9a512b 100644
--- a/backend/src/graphql/resolver/GdtResolver.ts
+++ b/backend/src/graphql/resolver/GdtResolver.ts
@@ -22,8 +22,7 @@ export class GdtResolver {
   ): Promise<GdtEntryList> {
     // load user
     const userRepository = getCustomRepository(UserRepository)
-    const pubKeyString = Buffer.from(context.pubKey).toString('hex')
-    const userEntity = await userRepository.findByPubkeyHex(pubKeyString)
+    const userEntity = await userRepository.findByPubkeyHex(context.pubKey)
 
     const resultGDT = await apiGet(
       `${CONFIG.GDT_API_URL}/GdtEntries/listPerEmailApi/${userEntity.email}/${currentPage}/${pageSize}/${order}`,
diff --git a/backend/src/graphql/resolver/TransactionResolver.ts b/backend/src/graphql/resolver/TransactionResolver.ts
index fbdbaf1bc..968ce9d4c 100644
--- a/backend/src/graphql/resolver/TransactionResolver.ts
+++ b/backend/src/graphql/resolver/TransactionResolver.ts
@@ -473,8 +473,7 @@ export class TransactionResolver {
   ): Promise<TransactionList> {
     // load user
     const userRepository = getCustomRepository(UserRepository)
-    const pubKeyString = Buffer.from(context.pubKey).toString('hex')
-    const userEntity = await userRepository.findByPubkeyHex(pubKeyString)
+    const userEntity = await userRepository.findByPubkeyHex(context.pubKey)
 
     const transactions = await listTransactions(currentPage, pageSize, order, userEntity)
 
@@ -509,8 +508,7 @@ export class TransactionResolver {
     // TODO this is subject to replay attacks
     // validate sender user (logged in)
     const userRepository = getCustomRepository(UserRepository)
-    const pubKeyString = Buffer.from(context.pubKey).toString('hex')
-    const senderUser = await userRepository.findByPubkeyHex(pubKeyString)
+    const senderUser = await userRepository.findByPubkeyHex(context.pubKey)
     if (senderUser.pubkey.length !== 32) {
       throw new Error('invalid sender public key')
     }
diff --git a/backend/src/graphql/resolver/UserResolver.ts b/backend/src/graphql/resolver/UserResolver.ts
index 436aee075..ad04a0e9f 100644
--- a/backend/src/graphql/resolver/UserResolver.ts
+++ b/backend/src/graphql/resolver/UserResolver.ts
@@ -621,8 +621,7 @@ export class UserResolver {
   @Query(() => Boolean)
   async hasElopage(@Ctx() context: any): Promise<boolean> {
     const userRepository = getCustomRepository(UserRepository)
-    const pubKey = Buffer.from(context.pubKey).toString('hex')
-    const userEntity = await userRepository.findByPubkeyHex(pubKey).catch()
+    const userEntity = await userRepository.findByPubkeyHex(context.pubKey).catch()
     if (!userEntity) {
       return false
     }