Microelectromechanical accelerometer and acceleration sensing methods. A file encryption unit generates a file key arbitrarily, encrypts the file key using the key information, encrypts a plaintext using the file key to generate a ciphertext, and stores an encrypted file including the encrypted file key in its header part and the ciphertext in its data part. The implant can be positioned between the adjacent spinous processes and once positioned, the implant can be arranged in a second configuration. Other embodiments are also described. By heating the at least one arched beam of the microactuator, the arched beams will further arch.