Let's seriously discuss smart guns
But first, regular "dumb" guns.
A firearm works by igniting a small charge of propellant at the end of a closed tube. The propellant pushes a projectile, a bullet, down the tube at a high rate of speed. The tube, called the barrel, almost always has grooves cut into it to make the bullet spin for purposes of stability; it's the same effect that a quarterback's throwing arm has on a football.
The propellant is ignited by an even smaller charge of an explosive called a primer. The primer, unlike the propellant, is impact-sensitive. It is detonated by the sharp impact of a tiny hard rod called a firing pin and makes a spark of flame.
The combination of bullet, propellant, and primer is contained in a case, typically brass (but steel and aluminum can be used), and is what is loaded into guns as a unit. It's commonly called a cartridge or a "round of ammunition".
The firing mechanisms of guns have been all about the details of how the parts work together to make that impact happen. Naturally, there are many different ways of doing the same thing and the various gun makers have addressed personal preference and other considerations by offering a variety of different products.
There are a myriad of other considerations that gun makers have to consider; for example, the mechanism that extracts used cases and loads fresh rounds, safety mechanisms, magazines, sights, protective finishes, ergonomics, controls, and ease of disassembly and cleaning.
Dumb guns are purely mechanical devices; there is a system of levers and springs and cams and other parts that do a certain task when actuated by the user. There are a variety of different ways to do this coming from different parts of history as well as different philosophies of gun use, but regardless of whether you're shooting the latest Heckler & Koch or a 1873 Colt Peacemaker you're shooting a purely mechanical device.
The concept of the smart gun is that, within that mechanical system there is an electronic element added. The electronic element would prevent the mechanical system from working until and unless a variety of conditions are met. The goal is that only the owner of the gun (and presumably whoever the gun owner trusts) would be able to get that gun to fire.
Let's discuss this electronic element. Broadly, it must do two things: recognize the person trying to pull the trigger and enable/disable the firing mechanism. Let's go after the recognition first.
How does the gun recognize the person pulling the trigger? Several methods have been proposed, including fingerprint/palmprint readers and the wearing of some sort of transponder by the owner. The difficulties of the former I think are pretty well known, especially if you have a smartphone with a fingerprint reader. Sweat, blood, dirt, grime, gloves, and poor positioning can all give false negatives to a scanner. On the plus side, the method is checking something that is an inherent feature of the shooter, or biometric.
Transponders have to be worn by the shooter; the typical methods proposed are some sort of ring or bracelet. This would likely solve the false-negative issue but it introduces two other issues: it is not tied to an inherent feature of the shooter and it works at a distance from the gun.
The use of a transponder would require the owner to either wear the transponder constantly or to have it stored where is could be accessed easily. Since a logical place would be to have the transponder near or in the gun-storage device, this would perhaps not have the anti-theft deterrent one would hope. In either case, the transponder could be stolen along with the gun (remember, carrying a gun is not a guarantee of successful defense).
The transponder also has a detection range associated with it, perhaps inches, perhaps several feet, and this itself is a weakness. If the detection range is very short, then a weak battery could make transponder activation sporadic (remember, cold weather weakens even fresh batteries). Also, if a person is wearing the transponder on one hand and is forced to move the gun to the other hand, the gun might not work unless the person was wearing two transponders.
If the detection range is longer, then if an attacker is able to wrest the gun from the legitimate owner, the gun can still be used by the attacker as long as he is still in proximity to the transponder... which is where you would have to be to have wrested the gun out of somebody's hand.
And of course, the detection method would have the usual potential problems of size (guns aren't very big and don't have a lot of free room in them) and battery life and being able to withstand the pounding of thousands of rounds of ammunition without malfunction.
Now the mechanism itself. The smart gun technology, once it positively identifies the shooter, must enable the firing mechanism. This would probably be accomplished by a little solenoid or actuator unlocking a final safety such as a firing-pin blocker as the trigger is pulled, although I can also envision something like a transfer-bar safety linked, not to the trigger mechanism, but to a solenoid or actuator.
Now, once a gun is stolen the gun's system won't activate the mechanism. But how hard would it be to remove or bypass that system? Admittedly, it would have to be done long after the gun was stolen; the criminal couldn't use the just-stolen gun until he had time to take it apart and bypass the system. But how would that really inhibit the black market in guns?
So these are the difficulties with making a smart gun. Professionals that carry guns will not tolerate the potential unreliability of such a system. When a cop at a domestic disturbance call goes for his gun, he or she can't afford to be worried about if the gun will go off when needed. They simply will not tolerate losing the mechanical reliability of their all-mechanical pistol. And this mentality is replicated in private security, the military (regular and special ops), and private citizens as well. It's a mentality for survival that transcends specific careers. They will not trade in the reliability of their Glock for a gun with the reliability of an 18th-century flintlock.
In my opinion there is no conspiracy to suppress smart guns; there simply isn't any market for them. The people that own or carry guns for self-defense won't accept reliability issues, and indeed often spend money on custom work to refine the firing mechanisms.
The people that own guns strictly for sporting use can keep them disassembled and/or in a large safe with a good lock. They will not take any reliability issues in the field while hunting or at the competition range, but when they're home the guns are secured without the intention of being ready and available for self-defense.
= new reply since forum marked as read
...I hope they don't run on a Microsoft OS. 
As a response 
Well said Krispos. You raised the bar, though it didn't help.
My thoughts on the exchange:
But since you endorse bringing technologies that are/might be adopted by the cops to the civilian marketplace I suppose that means you would make this fine catalog of equipment available to the people --
Check this out, it's on backwards. This was during Boston.
Remember these are the same people who want full auto weapons.
https://www.google.com/imgres?imgurl=
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Have a dash of Linux: "Since we're going out for dinner, let me df my wallet." 
