A method and apparatus for generating a non-interactive key, and a method for communication security using the same. Torsion elements, which may be disposed in concentric groups, each have one end disposed at and resisting rotation relative to the arm but permitting flexural movement relative to the arm. The leg portions are formed longitudinally near two sides of the base so that the body has a substantially U-shaped cross section. The cryptography circuit may implement an algorithm and use a key to provide a predetermined security level, such as up to Type 1 security, although lower levels may also be implemented. A ramp modulation signal may be generated.