Please help me

The teacher is asking me to do a comparison of secure and insecure string concentration. I know what a secure string concentration is, but I'm not sure how to interpret what he means by insecure. The best guess I have is that an insecure string concentration is a function that doesn't function.
I tried searching online for an answer but couldn't find anything.
The help would be appreciated; thank you!

my code for secure string concentration:

void setup() {
// put your setup code here, to run once:
Serial.begin (9600);

void loop() {
// put your main code here, to run repeatedly:
addstring("meat", "cheese", "buns", 5);

void addstring(String meat, String cheese, String buns, int a){
String result = meat + cheese + buns;
result += " is ";
String Age = String(a);
result += Age;
result += " years old";

You can't ask your teacher what they mean by secure/insecure? It seems fairly important to understand if you're doing an assignment.

However, if you do know what "secure" means, then isn't it fairly straightforward what "insecure" is? It means, "not secure"...

Did you mean “concatenation”?

Having a good search term always helps.