diff --git a/src/main/java/com/alibaba/druid/filter/config/ConfigTools.java b/src/main/java/com/alibaba/druid/filter/config/ConfigTools.java
index c61fa33900..bd94b6849f 100644
--- a/src/main/java/com/alibaba/druid/filter/config/ConfigTools.java
+++ b/src/main/java/com/alibaba/druid/filter/config/ConfigTools.java
@@ -30,7 +30,6 @@ import java.security.cert.Certificate;
 import java.security.cert.CertificateFactory;
 import java.security.interfaces.RSAPublicKey;
 import java.security.spec.PKCS8EncodedKeySpec;
-import java.security.spec.RSAPrivateCrtKeySpec;
 import java.security.spec.RSAPrivateKeySpec;
 import java.security.spec.X509EncodedKeySpec;