XNOR gate
The XNOR gate (sometimes ENOR, EXNOR, NXOR, XAND and pronounced as exclusive NOR) is a digital logic gate whose function is the logical complement of the exclusive OR (XOR) gate. It is equivalent to the logical connective ( ↔ {\displaystyle \leftrightarrow } ) from mathematical logic, also known as the material biconditional.