How to blow the MSP430 security fuse
According to TI appnote SLAU320 the fuse is blown by applying Vpp to TEST pin:


But later down in the document it also says this in a subsection of the reference 1.4.1:



Which indicates that you apply the Vpp voltage, then setup the fuse blowing by writing on the JTAG interface. The IR_PREPARE_BLOW and IR_EX_BLOW are described in the document.