Locate the file customApplicationContext.xml in \apache-tomcat-8.5.14\webapps\jw\WEB-INF\classes and add in line 6-9 as shown below.
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="dataEncryption" class="org.joget.apps.workflow.security.SecureDataEncryptionImpl">
<property name="salt" value="NEW-VALUE-GOES-HERE"/>
<property name="key" value="NEW-VALUE-GOES-HERE"/>
</bean>
</beans>
Replace line 7 and 8 salt and key value to your own one.