diff --git a/api/build.gradle b/api/build.gradle
index 0f14bf25..752a4b09 100644
--- a/api/build.gradle
+++ b/api/build.gradle
@@ -4,8 +4,6 @@ plugins {
 }
 
 dependencies {
-	implementation "org.bouncycastle:bcpkix-jdk15to18:1.66"
-	
 	implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 	implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.9"
 	implementation "org.jetbrains.kotlinx:kotlinx-serialization-core:1.0.0"
diff --git a/api/src/main/kotlin/com/lhwdev/selfTestMacro/api/findUser.kt b/api/src/main/kotlin/com/lhwdev/selfTestMacro/api/findUser.kt
index 1cb99967..b4261062 100644
--- a/api/src/main/kotlin/com/lhwdev/selfTestMacro/api/findUser.kt
+++ b/api/src/main/kotlin/com/lhwdev/selfTestMacro/api/findUser.kt
@@ -13,11 +13,9 @@ import kotlinx.serialization.encoding.Encoder
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.jsonObject
 import kotlinx.serialization.json.jsonPrimitive
-import org.bouncycastle.jce.provider.BouncyCastleProvider
 import java.io.IOException
 import java.math.BigInteger
 import java.security.KeyFactory
-import java.security.Security
 import java.security.spec.RSAPublicKeySpec
 import javax.crypto.Cipher
 
@@ -68,17 +66,10 @@ suspend fun findUser(schoolInfo: SchoolInfo, request: GetUserTokenRequestBody) =
 
 lateinit var encodeBase64: (ByteArray) -> String
 
-private val sProvider = run {
-	Security.removeProvider("BC")
-	val provider = BouncyCastleProvider()
-	Security.addProvider(provider)
-	provider
-}
-
 
 suspend fun encrypt(string: String): String = ioTask {
 	val key = RSAPublicKeySpec(BigInteger("30718937712611605689191751047964347711554702318809238360089112453166217803395521606458190795722565177328746277011809492198037993902927400109154434682159584719442248913593972742086295960255192532052628569970645316811605886842040898815578676961759671712587342568414746446165948582657737331468733813122567503321355924190641302039446055143553127897636698729043365414410208454947672037202818029336707554263659582522814775377559532575089915217472518288660143323212695978110773753720635850393399040827859210693969622113812618481428838504301698541638186158736040620420633114291426890790215359085924554848097772407366395041461"), BigInteger("65537"))
-	val cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", sProvider)
+	val cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding")
 	cipher.init(Cipher.PUBLIC_KEY, KeyFactory.getInstance("RSA").generatePublic(key))
 	encodeBase64(cipher.doFinal(string.toByteArray()))
 }
diff --git a/app/build.gradle b/app/build.gradle
index 510c04b6..44e32e7a 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -48,8 +48,6 @@ android {
 dependencies {
 	implementation project(":api")
 	
-	implementation "androidx.multidex:multidex:2.0.1"
-	
 	implementation fileTree(dir: "libs", include: ["*.jar"])
 	implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 	implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.9"
diff --git a/app/src/main/java/com/lhwdev/selfTestMacro/MainApplication.kt b/app/src/main/java/com/lhwdev/selfTestMacro/MainApplication.kt
index 6fd5ce7b..02aa3a8f 100644
--- a/app/src/main/java/com/lhwdev/selfTestMacro/MainApplication.kt
+++ b/app/src/main/java/com/lhwdev/selfTestMacro/MainApplication.kt
@@ -1,10 +1,10 @@
 package com.lhwdev.selfTestMacro
 
-import androidx.multidex.MultiDexApplication
+import android.app.Application
 
 
 @Suppress("unused")
-class MainApplication : MultiDexApplication() {
+class MainApplication : Application() {
 	override fun onCreate() {
 		super.onCreate()
 		sDummyForInitialization