Public Key Certificates
Public keys are often contained in certificates. A user can digitally sign messages using his or her private key, and another user can verify the signature using the public key contained in the signer’s certificate, which was issued by a CA within the PKI. A public key certificate (sometimes called an identity certificate) [...]

If your company policy requires it, hardware components such as wireless features and microphones can be physically disabled (but only by an Apple Certified Technician). Physically disabling hardware may not be practical in all circumstances. You can also disable hardware by removing the software driver, because the operating system interfaces with hardware via kernel extensions [...]