diff --git a/komga/src/flyway/resources/db/migration/sqlite/V20210706162229__file_hash.sql b/komga/src/flyway/resources/db/migration/sqlite/V20210706162229__file_hash.sql
new file mode 100644
index 000000000..ceb54edfc
--- /dev/null
+++ b/komga/src/flyway/resources/db/migration/sqlite/V20210706162229__file_hash.sql
@@ -0,0 +1,2 @@
+ALTER TABLE BOOK
+    ADD COLUMN FILE_HASH varchar NOT NULL DEFAULT '';
diff --git a/komga/src/main/kotlin/org/gotson/komga/application/tasks/Task.kt b/komga/src/main/kotlin/org/gotson/komga/application/tasks/Task.kt
index fd33d31fd..ae227b264 100644
--- a/komga/src/main/kotlin/org/gotson/komga/application/tasks/Task.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/application/tasks/Task.kt
@@ -32,6 +32,11 @@ sealed class Task(priority: Int = DEFAULT_PRIORITY) : Serializable {
     override fun toString(): String = "RefreshBookMetadata(bookId='$bookId', capabilities=$capabilities, priority='$priority')"
   }
 
+  class HashBook(val bookId: String, priority: Int = DEFAULT_PRIORITY) : Task(priority) {
+    override fun uniqueId() = "HASH_BOOK_$bookId"
+    override fun toString(): String = "HashBook(bookId='$bookId', priority='$priority')"
+  }
+
   class RefreshSeriesMetadata(val seriesId: String, priority: Int = DEFAULT_PRIORITY) : Task(priority) {
     override fun uniqueId() = "REFRESH_SERIES_METADATA_$seriesId"
     override fun toString(): String = "RefreshSeriesMetadata(seriesId='$seriesId', priority='$priority')"
diff --git a/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskHandler.kt b/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskHandler.kt
index d8f0eeaca..5d4687bb5 100644
--- a/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskHandler.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskHandler.kt
@@ -44,6 +44,7 @@ class TaskHandler(
             libraryRepository.findByIdOrNull(task.libraryId)?.let { library ->
               libraryContentLifecycle.scanRootFolder(library)
               taskReceiver.analyzeUnknownAndOutdatedBooks(library)
+              taskReceiver.hashBooksWithoutHash(library)
               if (library.repairExtensions) taskReceiver.repairExtensions(library, LOWEST_PRIORITY)
               if (library.convertToCbz) taskReceiver.convertBooksToCbz(library, LOWEST_PRIORITY)
             } ?: logger.warn { "Cannot execute task $task: Library does not exist" }
@@ -103,6 +104,11 @@ class TaskHandler(
             bookRepository.findByIdOrNull(task.bookId)?.let { book ->
               bookConverter.repairExtension(book)
             } ?: logger.warn { "Cannot execute task $task: Book does not exist" }
+
+          is Task.HashBook ->
+            bookRepository.findByIdOrNull(task.bookId)?.let { book ->
+              bookLifecycle.hashAndPersist(book)
+            } ?: logger.warn { "Cannot execute task $task: Book does not exist" }
         }
       }.also {
         logger.info { "Task $task executed in $it" }
diff --git a/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskReceiver.kt b/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskReceiver.kt
index ffb54fbc9..a2e1f3743 100644
--- a/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskReceiver.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/application/tasks/TaskReceiver.kt
@@ -56,6 +56,12 @@ class TaskReceiver(
     }
   }
 
+  fun hashBooksWithoutHash(library: Library) {
+    bookRepository.findAllIdsByLibraryIdAndWithEmptyHash(library.id).forEach {
+      submitTask(Task.HashBook(it, LOWEST_PRIORITY))
+    }
+  }
+
   fun convertBooksToCbz(library: Library, priority: Int = DEFAULT_PRIORITY) {
     bookConverter.getConvertibleBookIds(library).forEach {
       submitTask(Task.ConvertBook(it, priority))
diff --git a/komga/src/main/kotlin/org/gotson/komga/domain/model/Book.kt b/komga/src/main/kotlin/org/gotson/komga/domain/model/Book.kt
index f92a3df90..4cd380a85 100644
--- a/komga/src/main/kotlin/org/gotson/komga/domain/model/Book.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/domain/model/Book.kt
@@ -13,6 +13,7 @@ data class Book(
   val url: URL,
   val fileLastModified: LocalDateTime,
   val fileSize: Long = 0,
+  val fileHash: String = "",
   val number: Int = 0,
 
   val id: String = TsidCreator.getTsid256().toString(),
diff --git a/komga/src/main/kotlin/org/gotson/komga/domain/persistence/BookRepository.kt b/komga/src/main/kotlin/org/gotson/komga/domain/persistence/BookRepository.kt
index 2325f25aa..e0a710711 100644
--- a/komga/src/main/kotlin/org/gotson/komga/domain/persistence/BookRepository.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/domain/persistence/BookRepository.kt
@@ -26,6 +26,7 @@ interface BookRepository {
   fun findAllIdsByLibraryId(libraryId: String): Collection<String>
   fun findAllIdsByLibraryIdAndMediaTypes(libraryId: String, mediaTypes: Collection<String>): Collection<String>
   fun findAllIdsByLibraryIdAndMismatchedExtension(libraryId: String, mediaType: String, extension: String): Collection<String>
+  fun findAllIdsByLibraryIdAndWithEmptyHash(libraryId: String): Collection<String>
   fun findAllIds(bookSearch: BookSearch, sort: Sort): Collection<String>
 
   fun insert(book: Book)
diff --git a/komga/src/main/kotlin/org/gotson/komga/domain/service/BookLifecycle.kt b/komga/src/main/kotlin/org/gotson/komga/domain/service/BookLifecycle.kt
index 578ec0bc7..f062ee2ce 100644
--- a/komga/src/main/kotlin/org/gotson/komga/domain/service/BookLifecycle.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/domain/service/BookLifecycle.kt
@@ -18,6 +18,7 @@ import org.gotson.komga.domain.persistence.MediaRepository
 import org.gotson.komga.domain.persistence.ReadListRepository
 import org.gotson.komga.domain.persistence.ReadProgressRepository
 import org.gotson.komga.domain.persistence.ThumbnailBookRepository
+import org.gotson.komga.infrastructure.hash.Hasher
 import org.gotson.komga.infrastructure.image.ImageConverter
 import org.gotson.komga.infrastructure.image.ImageType
 import org.springframework.stereotype.Service
@@ -41,6 +42,7 @@ class BookLifecycle(
   private val imageConverter: ImageConverter,
   private val eventPublisher: EventPublisher,
   private val transactionTemplate: TransactionTemplate,
+  private val hasher: Hasher,
 ) {
 
   fun analyzeAndPersist(book: Book): Boolean {
@@ -63,6 +65,16 @@ class BookLifecycle(
     return media.status == Media.Status.READY
   }
 
+  fun hashAndPersist(book: Book) {
+    logger.info { "Hash and persist book: $book" }
+    if (book.fileHash.isBlank()) {
+      val hash = hasher.computeHash(book.path)
+      bookRepository.update(book.copy(fileHash = hash))
+    } else {
+      logger.info { "Book already has a hash, skipping" }
+    }
+  }
+
   fun generateThumbnailAndPersist(book: Book) {
     logger.info { "Generate thumbnail and persist for book: $book" }
     try {
diff --git a/komga/src/main/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycle.kt b/komga/src/main/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycle.kt
index d4deade74..21734b3b4 100644
--- a/komga/src/main/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycle.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycle.kt
@@ -92,7 +92,8 @@ class LibraryContentLifecycle(
                   logger.info { "Book changed on disk, update and reset media status: $existingBook" }
                   val updatedBook = existingBook.copy(
                     fileLastModified = newBook.fileLastModified,
-                    fileSize = newBook.fileSize
+                    fileSize = newBook.fileSize,
+                    fileHash = "",
                   )
                   transactionTemplate.executeWithoutResult {
                     mediaRepository.findById(existingBook.id).let {
diff --git a/komga/src/main/kotlin/org/gotson/komga/infrastructure/hash/Hasher.kt b/komga/src/main/kotlin/org/gotson/komga/infrastructure/hash/Hasher.kt
new file mode 100644
index 000000000..827461ee8
--- /dev/null
+++ b/komga/src/main/kotlin/org/gotson/komga/infrastructure/hash/Hasher.kt
@@ -0,0 +1,33 @@
+package org.gotson.komga.infrastructure.hash
+
+import mu.KotlinLogging
+import org.apache.commons.codec.digest.XXHash32
+import org.springframework.stereotype.Component
+import java.nio.file.Path
+import kotlin.io.path.inputStream
+
+private val logger = KotlinLogging.logger {}
+
+private const val DEFAULT_BUFFER_SIZE = 4096
+private const val SEED = 0
+
+@Component
+class Hasher {
+
+  fun computeHash(path: Path): String {
+    logger.info { "Hashing: $path" }
+    val hash = XXHash32(SEED)
+
+    path.inputStream().use {
+      val buffer = ByteArray(DEFAULT_BUFFER_SIZE)
+      var len: Int
+
+      do {
+        len = it.read(buffer)
+        if (len >= 0) hash.update(buffer, 0, len)
+      } while (len >= 0)
+    }
+
+    return hash.value.toString(36)
+  }
+}
diff --git a/komga/src/main/kotlin/org/gotson/komga/infrastructure/jooq/BookDao.kt b/komga/src/main/kotlin/org/gotson/komga/infrastructure/jooq/BookDao.kt
index 291d98a77..ed69a38c0 100644
--- a/komga/src/main/kotlin/org/gotson/komga/infrastructure/jooq/BookDao.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/infrastructure/jooq/BookDao.kt
@@ -62,8 +62,7 @@ class BookDao(
       .map { it.toDomain() }
 
   override fun findAll(): Collection<Book> =
-    dsl.select(*b.fields())
-      .from(b)
+    dsl.selectFrom(b)
       .fetchInto(b)
       .map { it.toDomain() }
 
@@ -177,6 +176,13 @@ class BookDao(
       .and(b.URL.notLike("%.$extension"))
       .fetch(b.ID)
 
+  override fun findAllIdsByLibraryIdAndWithEmptyHash(libraryId: String): Collection<String> =
+    dsl.select(b.ID)
+      .from(b)
+      .where(b.LIBRARY_ID.eq(libraryId))
+      .and(b.FILE_HASH.eq(""))
+      .fetch(b.ID)
+
   @Transactional
   override fun insert(book: Book) {
     insert(listOf(book))
@@ -194,9 +200,10 @@ class BookDao(
           b.NUMBER,
           b.FILE_LAST_MODIFIED,
           b.FILE_SIZE,
+          b.FILE_HASH,
           b.LIBRARY_ID,
           b.SERIES_ID
-        ).values(null as String?, null, null, null, null, null, null, null)
+        ).values(null as String?, null, null, null, null, null, null, null, null)
       ).also { step ->
         books.forEach {
           step.bind(
@@ -206,6 +213,7 @@ class BookDao(
             it.number,
             it.fileLastModified,
             it.fileSize,
+            it.fileHash,
             it.libraryId,
             it.seriesId
           )
@@ -231,6 +239,7 @@ class BookDao(
       .set(b.NUMBER, book.number)
       .set(b.FILE_LAST_MODIFIED, book.fileLastModified)
       .set(b.FILE_SIZE, book.fileSize)
+      .set(b.FILE_HASH, book.fileHash)
       .set(b.LIBRARY_ID, book.libraryId)
       .set(b.SERIES_ID, book.seriesId)
       .set(b.LAST_MODIFIED_DATE, LocalDateTime.now(ZoneId.of("Z")))
@@ -269,6 +278,7 @@ class BookDao(
       url = URL(url),
       fileLastModified = fileLastModified,
       fileSize = fileSize,
+      fileHash = fileHash,
       id = id,
       libraryId = libraryId,
       seriesId = seriesId,
diff --git a/komga/src/test/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycleTest.kt b/komga/src/test/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycleTest.kt
index 5b781618f..7b584cae1 100644
--- a/komga/src/test/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycleTest.kt
+++ b/komga/src/test/kotlin/org/gotson/komga/domain/service/LibraryContentLifecycleTest.kt
@@ -16,6 +16,7 @@ import org.gotson.komga.domain.persistence.BookRepository
 import org.gotson.komga.domain.persistence.LibraryRepository
 import org.gotson.komga.domain.persistence.MediaRepository
 import org.gotson.komga.domain.persistence.SeriesRepository
+import org.gotson.komga.infrastructure.hash.Hasher
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.extension.ExtendWith
@@ -42,6 +43,9 @@ class LibraryContentLifecycleTest(
   @MockkBean
   private lateinit var mockAnalyzer: BookAnalyzer
 
+  @MockkBean
+  private lateinit var mockHasher: Hasher
+
   @AfterEach
   fun `clear repositories`() {
     libraryRepository.findAll().forEach {
@@ -229,7 +233,7 @@ class LibraryContentLifecycleTest(
   }
 
   @Test
-  fun `given existing Book with different last modified date when rescanning then media is marked as outdated`() {
+  fun `given existing Book with different last modified date when rescanning then media is marked as outdated and hash is reset`() {
     // given
     val library = makeLibrary()
     libraryRepository.insert(library)
@@ -243,7 +247,12 @@ class LibraryContentLifecycleTest(
     libraryContentLifecycle.scanRootFolder(library)
 
     every { mockAnalyzer.analyze(any()) } returns Media(status = Media.Status.READY, mediaType = "application/zip", pages = mutableListOf(makeBookPage("1.jpg"), makeBookPage("2.jpg")), bookId = book1.id)
-    bookRepository.findAll().map { bookLifecycle.analyzeAndPersist(it) }
+    every { mockHasher.computeHash(any()) }.returnsMany("abc", "def")
+
+    bookRepository.findAll().map {
+      bookLifecycle.analyzeAndPersist(it)
+      bookLifecycle.hashAndPersist(it)
+    }
 
     // when
     libraryContentLifecycle.scanRootFolder(library)
@@ -251,9 +260,11 @@ class LibraryContentLifecycleTest(
     // then
     verify(exactly = 2) { mockScanner.scanRootFolder(any()) }
     verify(exactly = 1) { mockAnalyzer.analyze(any()) }
+    verify(exactly = 1) { mockHasher.computeHash(any()) }
 
     bookRepository.findAll().first().let { book ->
       assertThat(book.lastModifiedDate).isNotEqualTo(book.createdDate)
+      assertThat(book.fileHash).isEmpty()
 
       mediaRepository.findById(book.id).let { media ->
         assertThat(media.status).isEqualTo(Media.Status.OUTDATED)
diff --git a/komga/src/test/kotlin/org/gotson/komga/infrastructure/jooq/BookDaoTest.kt b/komga/src/test/kotlin/org/gotson/komga/infrastructure/jooq/BookDaoTest.kt
index 94eba3e4f..2b0b69a11 100644
--- a/komga/src/test/kotlin/org/gotson/komga/infrastructure/jooq/BookDaoTest.kt
+++ b/komga/src/test/kotlin/org/gotson/komga/infrastructure/jooq/BookDaoTest.kt
@@ -1,6 +1,5 @@
 package org.gotson.komga.infrastructure.jooq
 
-import mu.KotlinLogging
 import org.assertj.core.api.Assertions.assertThat
 import org.gotson.komga.domain.model.Book
 import org.gotson.komga.domain.model.BookSearch
@@ -57,6 +56,7 @@ class BookDaoTest(
       url = URL("file://book"),
       fileLastModified = now,
       fileSize = 3,
+      fileHash = "abc",
       seriesId = series.id,
       libraryId = library.id
     )
@@ -71,6 +71,7 @@ class BookDaoTest(
     assertThat(created.url).isEqualTo(book.url)
     assertThat(created.fileLastModified).isEqualToIgnoringNanos(book.fileLastModified)
     assertThat(created.fileSize).isEqualTo(book.fileSize)
+    assertThat(created.fileHash).isEqualTo(book.fileHash)
   }
 
   @Test
@@ -92,7 +93,8 @@ class BookDaoTest(
         name = "Updated",
         url = URL("file://updated"),
         fileLastModified = modificationDate,
-        fileSize = 5
+        fileSize = 5,
+        fileHash = "def",
       )
     }
 
@@ -108,6 +110,7 @@ class BookDaoTest(
     assertThat(modified.url).isEqualTo(URL("file://updated"))
     assertThat(modified.fileLastModified).isEqualToIgnoringNanos(modificationDate)
     assertThat(modified.fileSize).isEqualTo(5)
+    assertThat(modified.fileHash).isEqualTo("def")
   }
 
   @Test
@@ -188,34 +191,4 @@ class BookDaoTest(
 
     assertThat(bookDao.count()).isEqualTo(0)
   }
-
-  private val logger = KotlinLogging.logger {}
-
-//  @Test
-//  fun benchmark() {
-//    val books = (1..10000).map {
-//      makeBook(it.toString(), libraryId = library.id, seriesId = series.id)
-//    }
-//
-//    val single = measureTime {
-//      books.map { bookDao.insert(it) }
-//    }
-//    bookDao.deleteAll()
-//
-//    val singleBatch = measureTime {
-//      books.map { bookDao.insertBatch(it) }
-//    }
-//    bookDao.deleteAll()
-//
-//    val transaction = measureTime {
-//      bookDao.insertMany(books)
-//    }
-//    bookDao.deleteAll()
-//
-//    logger.info { "Single: $single" }
-//    logger.info { "SingleBatch: $singleBatch" }
-//    logger.info { "Transaction: $transaction" }
-//
-//    assertThat(single).isEqualTo(transaction)
-//  }
 }