add changeBond interface

Helius

2020-06-02 46a4a7b1a83d733aee95dcfe156ff3f1302632ac

 src/main/java/com/xcong/excoin/configurations/properties/SecurityProperties.java

@@ -14,4 +14,6 @@
public class SecurityProperties {

    private String privateKey;

    private String publicKey;
}