Embodiments include a computing processor control flow enforcement system including a processor, a block cipher encryption circuit, and an exclusive-OR (XOR) circuit. The control flow enforcement system uses a block cipher encryption to authenticate a return address when returning from a call or interrupt. The block cipher encryption circuit executes a block cipher encryption on a first number including an identifier to produce a first encrypted result and executes a block cipher encryption on a second number including a return address and a stack location pointer to produce a second encrypted result. The XOR circuit performs an XOR operation on the first encrypted result and the second encrypted result to produce a message authentication code tag.