diff --git a/src/UniqueExtractor.php b/src/UniqueExtractor.php
index a3c8aac..d3a891f 100644
--- a/src/UniqueExtractor.php
+++ b/src/UniqueExtractor.php
@@ -36,7 +36,7 @@ public static function getString($var, bool $strict): string
     {
         switch (true) {
             case is_array($var):
-                return 'array_'.md5(serialize($var));
+                return 'array_'.serialize($var);
             case is_resource($var):
                 preg_match('/#([0-9]+)$/', (string)$var, $matches);
                 return 'resource_'.$matches[1];
@@ -45,7 +45,7 @@ public static function getString($var, bool $strict): string
             case $var instanceof Closure:
                 return 'closure_'.spl_object_id($var);
             case is_object($var):
-                return 'object_'.($strict ? spl_object_id($var) : md5(serialize($var)));
+                return 'object_'.($strict ? spl_object_id($var) : serialize($var));
             case gettype($var) === 'boolean':
                 return 'boolean_'.(int)$var;
             case $strict:
diff --git a/tests/unit/UniqueExtractor/NonStrictTest.php b/tests/unit/UniqueExtractor/NonStrictTest.php
index 9ab736c..5fabe63 100644
--- a/tests/unit/UniqueExtractor/NonStrictTest.php
+++ b/tests/unit/UniqueExtractor/NonStrictTest.php
@@ -68,23 +68,23 @@ public function dataProviderForStringNonStrict(): array
             ['Abc', 'scalar_Abc'],
 
             // arrays
-            [[], 'array_'.md5(serialize([]))],
-            [[0], 'array_'.md5(serialize([0]))],
-            [[1], 'array_'.md5(serialize([1]))],
-            [[1, 2, 3], 'array_'.md5(serialize([1, 2, 3]))],
-            [[1, 2, '3'], 'array_'.md5(serialize([1, 2, '3']))],
-            [['a', 'b', 'c'], 'array_'.md5(serialize(['a', 'b', 'c']))],
-            [['a' => [1, 2, 3], [4, 5, 6]], 'array_'.md5(serialize(['a' => [1, 2, 3], [4, 5, 6]]))],
+            [[], 'array_'.serialize([])],
+            [[0], 'array_'.serialize([0])],
+            [[1], 'array_'.serialize([1])],
+            [[1, 2, 3], 'array_'.serialize([1, 2, 3])],
+            [[1, 2, '3'], 'array_'.serialize([1, 2, '3'])],
+            [['a', 'b', 'c'], 'array_'.serialize(['a', 'b', 'c'])],
+            [['a' => [1, 2, 3], [4, 5, 6]], 'array_'.serialize(['a' => [1, 2, 3], [4, 5, 6]])],
 
             // stdClass objects
-            [(object)[], 'object_'.md5(serialize((object)[]))],
-            [(object)[1, 2, 3], 'object_'.md5(serialize((object)[1, 2, 3]))],
-            [(object)['a' => 1], 'object_'.md5(serialize((object)['a' => 1]))],
-            [(object)['a' => [1, 2, 3]], 'object_'.md5(serialize((object)['a' => [1, 2, 3]]))],
+            [(object)[], 'object_'.serialize((object)[])],
+            [(object)[1, 2, 3], 'object_'.serialize((object)[1, 2, 3])],
+            [(object)['a' => 1], 'object_'.serialize((object)['a' => 1])],
+            [(object)['a' => [1, 2, 3]], 'object_'.serialize((object)['a' => [1, 2, 3]])],
 
             // another objects
-            [new SerializableFixture(1), 'object_'.md5(serialize(new SerializableFixture(1)))],
-            [new SerializableFixture(2), 'object_'.md5(serialize(new SerializableFixture(2)))],
+            [new SerializableFixture(1), 'object_'.serialize(new SerializableFixture(1))],
+            [new SerializableFixture(2), 'object_'.serialize(new SerializableFixture(2))],
 
             // closures
             [$func = function() {}, 'closure_'.spl_object_id($func)],
@@ -158,23 +158,23 @@ public function dataProviderForHashNonStrict(): array
             ['Abc', md5('scalar_Abc')],
 
             // arrays
-            [[], md5('array_'.md5(serialize([])))],
-            [[0], md5('array_'.md5(serialize([0])))],
-            [[1], md5('array_'.md5(serialize([1])))],
-            [[1, 2, 3], md5('array_'.md5(serialize([1, 2, 3])))],
-            [[1, 2, '3'], md5('array_'.md5(serialize([1, 2, '3'])))],
-            [['a', 'b', 'c'], md5('array_'.md5(serialize(['a', 'b', 'c'])))],
-            [['a' => [1, 2, 3], [4, 5, 6]], md5('array_'.md5(serialize(['a' => [1, 2, 3], [4, 5, 6]])))],
+            [[], md5('array_'.serialize([]))],
+            [[0], md5('array_'.serialize([0]))],
+            [[1], md5('array_'.serialize([1]))],
+            [[1, 2, 3], md5('array_'.serialize([1, 2, 3]))],
+            [[1, 2, '3'], md5('array_'.serialize([1, 2, '3']))],
+            [['a', 'b', 'c'], md5('array_'.serialize(['a', 'b', 'c']))],
+            [['a' => [1, 2, 3], [4, 5, 6]], md5('array_'.serialize(['a' => [1, 2, 3], [4, 5, 6]]))],
 
             // stdClass objects
-            [(object)[], md5('object_'.md5(serialize((object)[])))],
-            [(object)[1, 2, 3], md5('object_'.md5(serialize((object)[1, 2, 3])))],
-            [(object)['a' => 1], md5('object_'.md5(serialize((object)['a' => 1])))],
-            [(object)['a' => [1, 2, 3]], md5('object_'.md5(serialize((object)['a' => [1, 2, 3]])))],
+            [(object)[], md5('object_'.serialize((object)[]))],
+            [(object)[1, 2, 3], md5('object_'.serialize((object)[1, 2, 3]))],
+            [(object)['a' => 1], md5('object_'.serialize((object)['a' => 1]))],
+            [(object)['a' => [1, 2, 3]], md5('object_'.serialize((object)['a' => [1, 2, 3]]))],
 
             // another objects
-            [new SerializableFixture(1), md5('object_'.md5(serialize(new SerializableFixture(1))))],
-            [new SerializableFixture(2), md5('object_'.md5(serialize(new SerializableFixture(2))))],
+            [new SerializableFixture(1), md5('object_'.serialize(new SerializableFixture(1)))],
+            [new SerializableFixture(2), md5('object_'.serialize(new SerializableFixture(2)))],
 
             // closures
             [$func = function() {}, md5('closure_'.spl_object_id($func))],
diff --git a/tests/unit/UniqueExtractor/StrictTest.php b/tests/unit/UniqueExtractor/StrictTest.php
index 7ce57e7..918694f 100644
--- a/tests/unit/UniqueExtractor/StrictTest.php
+++ b/tests/unit/UniqueExtractor/StrictTest.php
@@ -68,13 +68,13 @@ public function dataProviderForString(): array
             ['Abc', 'string_Abc'],
 
             // arrays
-            [[], 'array_'.md5(serialize([]))],
-            [[0], 'array_'.md5(serialize([0]))],
-            [[1], 'array_'.md5(serialize([1]))],
-            [[1, 2, 3], 'array_'.md5(serialize([1, 2, 3]))],
-            [[1, 2, '3'], 'array_'.md5(serialize([1, 2, '3']))],
-            [['a', 'b', 'c'], 'array_'.md5(serialize(['a', 'b', 'c']))],
-            [['a' => [1, 2, 3], [4, 5, 6]], 'array_'.md5(serialize(['a' => [1, 2, 3], [4, 5, 6]]))],
+            [[], 'array_'.serialize([])],
+            [[0], 'array_'.serialize([0])],
+            [[1], 'array_'.serialize([1])],
+            [[1, 2, 3], 'array_'.serialize([1, 2, 3])],
+            [[1, 2, '3'], 'array_'.serialize([1, 2, '3'])],
+            [['a', 'b', 'c'], 'array_'.serialize(['a', 'b', 'c'])],
+            [['a' => [1, 2, 3], [4, 5, 6]], 'array_'.serialize(['a' => [1, 2, 3], [4, 5, 6]])],
 
             // stdClass objects
             [$obj = (object)[], 'object_'.spl_object_id($obj)],
@@ -158,13 +158,13 @@ public function dataProviderForHash(): array
             ['Abc', md5('string_Abc')],
 
             // arrays
-            [[], md5('array_'.md5(serialize([])))],
-            [[0], md5('array_'.md5(serialize([0])))],
-            [[1], md5('array_'.md5(serialize([1])))],
-            [[1, 2, 3], md5('array_'.md5(serialize([1, 2, 3])))],
-            [[1, 2, '3'], md5('array_'.md5(serialize([1, 2, '3'])))],
-            [['a', 'b', 'c'], md5('array_'.md5(serialize(['a', 'b', 'c'])))],
-            [['a' => [1, 2, 3], [4, 5, 6]], md5('array_'.md5(serialize(['a' => [1, 2, 3], [4, 5, 6]])))],
+            [[], md5('array_'.serialize([]))],
+            [[0], md5('array_'.serialize([0]))],
+            [[1], md5('array_'.serialize([1]))],
+            [[1, 2, 3], md5('array_'.serialize([1, 2, 3]))],
+            [[1, 2, '3'], md5('array_'.serialize([1, 2, '3']))],
+            [['a', 'b', 'c'], md5('array_'.serialize(['a', 'b', 'c']))],
+            [['a' => [1, 2, 3], [4, 5, 6]], md5('array_'.serialize(['a' => [1, 2, 3], [4, 5, 6]]))],
 
             // stdClass objects
             [$obj = (object)[], md5('object_'.spl_object_id($obj))],