What Is Linear Feedback Shift Register (LFSR)?

A linear feedback shift register is a bit of digital magic that can be used to do all kinds of cool things. The most common use for LSFRs is to make a counter—they're used in everything from clocks and timers to computer memory chips. When you tap into an LSFR, you get an output dependent on the input. This is where the name "linear" comes from: when you look at the output as a function of your input, it looks like a line (or graph). LSFRs also have cryptography and circuit testing applications: in cryptography, they're used for public-key encryption; in-circuit testing, they help determine how well your circuits are operating. Linear feedback shift registers are great, but they're not always the best option. If you need to take a linear function and turn it into a nonlinear function, you might consider using an Exclusive OR (XOR) gate. An XOR gate takes two inputs and outputs a 1 if their values are different or 0 if they're the same. As a result, an XOR gate can be used as an input for a linear feedback shift register because it will produce a unique output for every possible input value. The Least Significant Floating-point Register is a tiny thing you can use to store a number. It can be accessed anytime, so it's great for storing things like passwords or PINs. You can also use it to store numbers related to your bank account or credit balance. If you're looking for something a little more advanced, the Least Significant Floating-point Register is also used in cryptography for pseudo-random number generation and pseudo-noise sequences. It's also often used for digital counters because it's so fast. This is handy because it allows us to create an infinite number of different outputs from a single input source—the only limit is our imagination!