Only information embedded in irreversible thermodynamic time is secure. Because only information embedded in thermodynamic time is computationally irreducible, and this kind of intelligence is uncopyable. Turing-computable intelligence is copyable, and copyable intelligence is insecure. Insecure information is finite and can be attacked and arbitrageurized. Therefore, Satoshi Nakamoto's decentralized consensus mechanism in Bitcoin is a starting point for security. Only information embedded in thermodynamic physical time is secure; all information based on authority is insecure. This insecure authority can come from any tangible organizational form: such as a finite group of nodes in a Proof-of-Stake (PoS) system, or other organizations. Open mathematical expressions are infinite, boundaries that cannot be expressed in mathematical language. Closed mathematical expressions are finite; finite means they can be expressed mathematically, computed by a Turing machine, and can be copied, deconstructed, attacked, and arbitrageurized.