diff --git a/compiler/src/main/kotlin/codegen/CodegenStep.kt b/compiler/src/main/kotlin/codegen/CodegenStep.kt
index 5c283f4..3214be0 100644
--- a/compiler/src/main/kotlin/codegen/CodegenStep.kt
+++ b/compiler/src/main/kotlin/codegen/CodegenStep.kt
@@ -154,6 +154,12 @@ abstract class CodegenStep {
       else -> value.takeIf { it.isNotEmpty() }
     }
 
+  fun KSAnnotation?.findIntArgument(name: String) =
+    when (val value = findArgument(name)?.value as? Int) {
+      null -> null
+      else -> value
+    }
+
   fun FileSpec.write(originatingDeclarations: Iterable<KSDeclaration>) =
     write(originatingDeclarations.mapNotNull { it.containingFile }.toSet())
 
@@ -188,7 +194,6 @@ abstract class CodegenStep {
   ) {
     val factoryClassName = className("PreferencesFactory")
     val factoryImplClassName = className("PreferencesFactoryImpl")
-    val objectTypeConverters = typeConverters.filter { it.classKind == ClassKind.OBJECT }
     val classTypeConverters = typeConverters.filter { it.classKind != ClassKind.OBJECT }
 
     val classTypeConvertersParams = classTypeConverters.map {
@@ -198,10 +203,6 @@ abstract class CodegenStep {
       )
     }
 
-    // If there are non-singleton TypeConverters, the user needs to manually inject
-    // them.
-    val needInjectTypeConverters = objectTypeConverters.isNotEmpty()
-
     fun mutableClassName(raw: KSClassDeclaration) =
       className("Mutable" + raw.simpleName.asString())
 
diff --git a/compiler/src/main/kotlin/codegen/PreferencesImplClasses.kt b/compiler/src/main/kotlin/codegen/PreferencesImplClasses.kt
index fae77b5..51757f2 100644
--- a/compiler/src/main/kotlin/codegen/PreferencesImplClasses.kt
+++ b/compiler/src/main/kotlin/codegen/PreferencesImplClasses.kt
@@ -48,6 +48,7 @@ import com.squareup.kotlinpoet.INT
 import com.squareup.kotlinpoet.KModifier
 import com.squareup.kotlinpoet.LONG
 import com.squareup.kotlinpoet.MemberName
+import com.squareup.kotlinpoet.MemberName.Companion.member
 import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.parameterizedBy
 import com.squareup.kotlinpoet.PropertySpec
 import com.squareup.kotlinpoet.SET
@@ -70,10 +71,24 @@ class PreferencesImplClasses : CodegenStep() {
     val mutableImplClassName = context.mutableImplClassName(preferences)
     val annotation = requireNotNull(preferences.findAnnotation(Preferences))
     val id = annotation.findStringArgument("id") ?: preferences.simpleName.asString()
+    val expires = annotation.findIntArgument("expires") ?: -1
+    val cryptKey = annotation.findStringArgument("cryptKey") ?: ""
 
     val mmkvPropertySpec = PropertySpec.builder("mmkv", MMKV)
       .addModifiers(KModifier.OVERRIDE)
-      .initializer("%T.mmkvWithID(%S)", MMKV, id)
+      .initializer(buildCodeBlock {
+        add("%T.mmkvWithID(%S", MMKV, id)
+        if (cryptKey.isNotEmpty()) {
+          add(", %M, %S)", MMKV.member("SINGLE_PROCESS_MODE"), cryptKey)
+        } else {
+          add(")")
+        }
+        if (expires > -1) {
+          beginControlFlow(".apply·{")
+          addStatement("enableAutoKeyExpire(%L)", expires)
+          endControlFlow()
+        }
+      })
       .build()
 
     val defaultPropertySpec = PropertySpec.builder("default", dataClassName)
diff --git a/integration-tests/generation/src/main/kotlin/model/CustomData.kt b/integration-tests/generation/src/main/kotlin/model/CustomData.kt
index d59e4a2..88fb698 100644
--- a/integration-tests/generation/src/main/kotlin/model/CustomData.kt
+++ b/integration-tests/generation/src/main/kotlin/model/CustomData.kt
@@ -22,7 +22,7 @@ import com.meowool.mmkv.ktx.PersistDefaultValue
 import com.meowool.mmkv.ktx.Preferences
 import java.util.Date
 
-@Preferences
+@Preferences(expires = 100, cryptKey = "abc")
 data class CustomData(
   @PersistDefaultValue
   val date: Date = Date(),
diff --git a/runtime/src/main/kotlin/Preferences.kt b/runtime/src/main/kotlin/Preferences.kt
index 399b981..39851c2 100644
--- a/runtime/src/main/kotlin/Preferences.kt
+++ b/runtime/src/main/kotlin/Preferences.kt
@@ -73,4 +73,18 @@ annotation class Preferences(
    * For example: `GeneralSettings` -> `generalSettings`.
    */
   val name: String = "",
+
+  /**
+   * The expiration time (in milliseconds) for the preferences.
+   * If set to a value greater than -1, the preferences will expire after the specified time.
+   * If set to -1 (the default value), the preferences will never expire.
+   */
+  val expires: Int = -1,
+
+  /**
+   * The encryption key to use for the preferences.
+   * If set to a non-empty string, the preferences will be encrypted using the specified key.
+   * If left empty (the default value), the preferences will not be encrypted.
+   */
+  val cryptKey: String = "",
 )