diff --git a/src/CryptKey.php b/src/CryptKey.php
index f3051d04..c707b223 100644
--- a/src/CryptKey.php
+++ b/src/CryptKey.php
@@ -79,19 +79,19 @@ class CryptKey
 
         if (!file_exists($keyPath) && !touch($keyPath)) {
             // @codeCoverageIgnoreStart
-            throw new \RuntimeException('"%s" key file could not be created', $keyPath);
+            throw new \RuntimeException(sprintf('"%s" key file could not be created', $keyPath));
             // @codeCoverageIgnoreEnd
         }
 
         if (file_put_contents($keyPath, $key) === false) {
             // @codeCoverageIgnoreStart
-            throw new \RuntimeException('Unable to write key file to temporary directory "%s"', $tmpDir);
+            throw new \RuntimeException(sprintf('Unable to write key file to temporary directory "%s"', $tmpDir));
             // @codeCoverageIgnoreEnd
         }
 
         if (chmod($keyPath, 0600) === false) {
             // @codeCoverageIgnoreStart
-            throw new \RuntimeException('The key file "%s" file mode could not be changed with chmod to 600', $keyPath);
+            throw new \RuntimeException(sprintf('The key file "%s" file mode could not be changed with chmod to 600', $keyPath));
             // @codeCoverageIgnoreEnd
         }