The Exclusive OR (XOR) is a logic gate capable of digitally implementing exclusive disjunction. XOR encryption is a simple symmetric cipher used in applications wherein security is not a primary requirement. XOR gates are used to execute binary addition in computers.

An elevated output results if only one of the outputs to the gate is high. If inputs turn low or both inputs are high, a low output results. The “military” and the “rectangular” are the two symbols for XOR gates.

Hardware and Pinout

XOR gates go under basic logic, and are thus identified in Complementary Metal Oxide Silicon (CMOS) and Transistor-Transistor Logic (TTL) integrated circuits. The 4070, the prevailing CMOS IC 4000 series, has four individual two-input pinout gates. To replace the less consistent 4030 while keeping the pinout, 4070 came out.

This mechanism is available from many semiconductor producers. It is typically available in DIL and SOIC formats.

Other Options

If XOR gates are unavailable, four NAND (Not AND) or five NOR (Not OR) gates can be used instead.

XOR operation is binary and designed for only two inputs, yet it is not uncommon in electronic design to hear of “XORing” more than two signals.

This means that, in the operation, the two initial signals are sent to an XOR gate. Then the gate’s output is fed to a second gate together with a third signal, and so on for the remaining signals. A circuit outputs “1”, when the quantity of 1’s at the inputs is odd, and a “0”, when the quantity of incoming 1’s is even. This renders it a valuable parity generator or Modulo-2 adder.