Unique Identifier (UID)

A UID is an identifier that uniquely identifies something within the set of all those things; meaning no two things will share the same value. Often UIDs are numeric “95673” or alphanumeric “cK7Bn4”. A UID does not need to be random or sequential, it just needs to be unique; the values {1, 2, 3, 4, 5} would be valid UIDs and obviously not random. UIDs are important in security, but need to be used correctly given that they do not need to be random. The length of a UID and the complexity of the characters effects the total size of the set of things the UID can represent.