X-NOR gate.
The output of x-nor gate is in state 1 only when it's two inputs are at the same states with respect to each other. X-NOR gate is also known as exclusive nor gate or E-NOR gate. It is a digital logic gate which is the reverse or complementary or inverse form of xor gate. X-NOR gate is the combination of xor and not gate. The logic symbol for x-nor gate is shown in the figure