What is a more unique delimiter than comma for separating strings?

| would be next on my list and is often used as an alternative to CSV. google “pipe delimited” and you will find many examples.

string[] items = new string[] {"Uno","Dos","Tres"};

string toEncrypt = String.Join("|", items);

items = toEncrypt.Split(new char[] {'|'}, StringSplitOptions.RemoveEmptyEntries);

foreach(string s in items)
  Console.WriteLine(s);

And since everyone likes to be a critic about the encoding and not provide the code, here is one way to encode the text so your | delim won’t collide.

string[] items = new string[] {"Uno","Dos","Tres"};

for (int i = 0; i < items.Length; i++)
    items[i] = Convert.ToBase64String(Encoding.UTF8.GetBytes(items[i]));

string toEncrypt = String.Join("|", items);

items = toEncrypt.Split(new char[] {'|'}, StringSplitOptions.RemoveEmptyEntries);

foreach (string s in items)
     Console.WriteLine(Encoding.UTF8.GetString(Convert.FromBase64String(s)));