What is CJSM? CJSM is a relatively secure email system that gives, Government Departments, Counsel and in theory some practitioners the confidence to send and exchange information classified at OFFICIAL (including information carrying the OFFICIAL – SENSITIVE marking1). CJSM uses dedicated email services to securely transmit emails between connected justice partners. You simply type the CJSM website address into your browser and then enter your username and password on the screen that appears. What is CJSM? Page 2. The CJSM secure email system. The Criminal Justice Secure eMail (CJSM) service allows people.