diff --git a/src/Document/Document.php b/src/Document/Document.php
index 7dbc634..f4db05d 100644
--- a/src/Document/Document.php
+++ b/src/Document/Document.php
@@ -20,6 +20,7 @@
 use PrinsFrank\PdfParser\Document\Object\Item\UncompressedObject\UncompressedObjectParser;
 use PrinsFrank\PdfParser\Document\Security\StandardSecurity;
 use PrinsFrank\PdfParser\Document\Version\Version;
+use PrinsFrank\PdfParser\Exception\AuthenticationFailedException;
 use PrinsFrank\PdfParser\Exception\NotImplementedException;
 use PrinsFrank\PdfParser\Exception\ParseFailureException;
 use PrinsFrank\PdfParser\Exception\PdfParserException;
@@ -40,8 +41,16 @@ public function __construct(
         public readonly CrossReferenceSource $crossReferenceSource,
         public ?StandardSecurity             $security,
     ) {
-        if ($this->getEncryptDictionary() !== null) {
-            throw new NotImplementedException('Encrypted documents are not supported yet');
+        if (($encryptDictionary = $this->getEncryptDictionary()) !== null) {
+            if ($encryptDictionary->getSecurityHandler() === null) {
+                throw new NotImplementedException('Empty security handler is not supported');
+            }
+
+            $this->security ??= new StandardSecurity();
+            if ($this->security->isUserPasswordValid($encryptDictionary, $crossReferenceSource->getFirstId()) === false
+                && $this->security->isOwnerPasswordValid($encryptDictionary, $crossReferenceSource->getFirstId()) === false) {
+                throw new AuthenticationFailedException($security === null ? 'Document could not be decrypted using default credentials, please supply an owner or user password' : 'User and owner password are invalid, please supply valid credentials');
+            }
         }
     }
 
diff --git a/tests/Samples/SamplesTest.php b/tests/Samples/SamplesTest.php
index 625b24b..e4b6976 100644
--- a/tests/Samples/SamplesTest.php
+++ b/tests/Samples/SamplesTest.php
@@ -6,6 +6,7 @@
 use PHPUnit\Framework\Attributes\CoversNothing;
 use PHPUnit\Framework\Attributes\DataProviderExternal;
 use PHPUnit\Framework\TestCase;
+use PrinsFrank\PdfParser\Document\Security\StandardSecurity;
 use PrinsFrank\PdfParser\Document\Version\Version;
 use PrinsFrank\PdfParser\PdfParser;
 use PrinsFrank\PdfParser\Tests\Samples\Info\FileInfo;
@@ -18,8 +19,10 @@
 class SamplesTest extends TestCase {
     /** @throws TypeError|ValueError|RuntimeException */
     #[DataProviderExternal(SampleProvider::class, 'samples')]
-    public function testExternalSourcePDFs(FileInfo $fileInfo): void {
-        $document = (new PdfParser())->parseFile($fileInfo->pdfPath);
+    public function testSamples(FileInfo $fileInfo): void {
+        $document = (new PdfParser())
+            ->parseFile($fileInfo->pdfPath, security: new StandardSecurity($fileInfo->userPassword, $fileInfo->ownerPassword));
+
         static::assertSame(Version::from(number_format($fileInfo->version / 10, 1)), $document->version);
         static::assertSame($fileInfo->title, $document->getInformationDictionary()?->getTitle());
         static::assertSame($fileInfo->producer, $document->getInformationDictionary()?->getProducer());