diff --git a/CHANGELOG.md b/CHANGELOG.md
index e214c68..df76ff8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
   encoding and a length of up to 64 characters. Implementing libraries MAY support additional characters and encodings
   or longer lengths, but must support at least that minimum.
   * Dashes (`-`) are now allowed in cache keys.
+  * The arbitrary maximum key length of 64 characters has been removed.
 
 
 ## [1.1.0] - 2024-03-02
diff --git a/src/CacheKey.php b/src/CacheKey.php
index 2ddca70..3a9d8f5 100644
--- a/src/CacheKey.php
+++ b/src/CacheKey.php
@@ -11,7 +11,7 @@ private function __construct(private readonly string $value) {}
 
     public static function fromString(string $value): self
     {
-        if (preg_match('/^[a-zA-Z0-9_.-]{1,64}$/u', $value) !== 1) {
+        if (preg_match('/^[a-zA-Z0-9_.-]+$/u', $value) !== 1) {
             throw InvalidArgument::invalidKey();
         }
 
diff --git a/tests/CacheKeyTest.php b/tests/CacheKeyTest.php
index 2bc75de..394b4cf 100644
--- a/tests/CacheKeyTest.php
+++ b/tests/CacheKeyTest.php
@@ -44,7 +44,6 @@ public static function invalidValues(): array
         return [
             'empty string' => [''],
             'invalid character' => ['\\'],
-            'too long' => [str_repeat('x', 65)],
         ];
     }
 }