Hello techsters -

I have a requirement wherein, in my application I want to facilitate creation of random numbers by one set of users who will then hand it over to other set of users. So for example a user A will want to create a key and give it to user B. User B will then use this key as a medium to look at some information being saved by user A at some other point of time. Hence it becomes mandatory to save the key that was generated by user A in the database. With the fact the key needs to be random and stored in the database the following is what I have thought as for the implementation:

My spring config file has the following bean definitions :

<bean id = "bytesKeyGenerator" class = "org.springframework.security.crypto.keygen.KeyGen erators"
factory-method="secureRandom">
<constructor-arg type="int" value="4"/>
</bean>

<bean id = "stringKeyGenerator" class =
"org.springframework.security.crypto.keygen.HexEnc odingStringKeyGenerator">
<constructor-arg ref="bytesKeyGenerator"></constructor-arg>
</bean>

In the application when the key needs to be generated, I would then get hold of the "stringKeyGenerator" bean and call its generateKey() method to generate the key. I would then set this key on a new instance of a custom class (for which there corresponds a table using JPA ) and store this custom object in the database These kind of keys will be generated very often. There is also a uniqueness constraint on the key column in this table that holds the custom object, here is a snapshot of the custom class.

@Entity
@Table(uniqueConstraints = @UniqueConstraint(columnNames = { "code" }))
public class CustomClass{

@NotNull
@Column(nullable=false)
private String code;

}

My question is - Would there be a chance of collision for the code value ? Is this a good way to implement ?
Any better suggestions would be really appreciated, If there is anything that the spring framework can help please do let me know.

Best Regards.