With the increasing threats of IP theft and cyberattack, security has changed from a feature to a basic requirement for any embedded application. The MSP432P4xx family of devices offers a number of security measures to meet the new security requirements including JTAG security, IP protection, and encryption-enabled bootloader (BSL) (formerly known as the bootstrap loader). In addition, the MSP432P4xx family does not compromise usability when adding the security options. In fact, it offers several methods to enable debugging when adding security or configuring BSL in the system. This application note covers the unique mailbox mechanism used to program and debug device security and BSL on MSP432™ MCUs. The application note also provides examples and guidance to add these features to an existing application.