Abstract: Magnetic stripe readers are disclosed that are configured to extract information from magnetic media and encrypt part of the extracted information. Embodiments of magnetic stripe readers include measures to resist tampering and inputs to receive unencrypted information from input devices. One embodiment includes a housing containing a magnetic reading head connected to a decoder circuit that is connected to an encryption engine. The magnetic reading head generates a signal indicative of a magnetic field. The decoder circuit is configured to extract data from the output of the magnetic reading head and the encryption engine is configured to encrypt a portion of the extracted data and the encryption engine is configured to pass a portion of the extracted data unencrypted.