diff --git a/src/main/java/com/github/ontio/sdk/claim/Claim.java b/src/main/java/com/github/ontio/sdk/claim/Claim.java
index 122541de..4a495238 100644
--- a/src/main/java/com/github/ontio/sdk/claim/Claim.java
+++ b/src/main/java/com/github/ontio/sdk/claim/Claim.java
@@ -27,10 +27,7 @@
 import com.alibaba.fastjson.JSON;
 import com.alibaba.fastjson.JSONObject;
 import com.github.ontio.crypto.SignatureScheme;
-import com.github.ontio.sdk.wallet.Identity;
-import sun.misc.BASE64Encoder;
 
-import java.security.spec.AlgorithmParameterSpec;
 import java.text.SimpleDateFormat;
 import java.util.*;