Information sharing is built into the universe, and so is copying of patterns. Atoms and molecules share electrons in predictable ways, cells communicate with each other, living entities communicate and share in incredibly diverse and complex ways; and once "the cat is out of the bag" it's almost impossible to get it back in. Streisand effects ad nauseum. The war living things wage against each other on so many levels - for example, viruses versus our immune systems - are also a facet of this interaction. We exist in an environment where sharing and communication is fundamental and everything influences everything else in myriad, complex ways. Making something totally secure - in other words, preventing it from interacting with its environment - hence is utterly impossible, or at the very least the amount of energy required to secure something is immense and the result is always imperfect.
Goes for plagiairism as well. DNA copies itself, kids copy their parents, we copy habits and patterns from each other hundreds of times every day. It's part of our processes for optimalisation and they're also intrinsic to the universe. Thus, things like copyright are also doomed to fail. Here, too, the amount of energy required is huge.
