APDU buffer

An APDU buffer is the buffer where the messages sent (received) by the card depart from (arrive to). The JCRE owns an APDU object (which is a JCRE Entry Point and an instance of the javacard. framework.APDU class) that encapsulates APDU messages in an internal byte array, called the APDU
buffer. This object is made accessible to the currently selected applet when needed, but any permanent access (out-of selection-scope) is strictly prohibited for security reasons.