A month ago my antitheft light started blinking fast and my card shut shut down now it wont start and the theft light is still on..

If its an aftermarket alarm and malfunctioning then you probably need to override it temporarily with your valet switch. What type of vehicle is it, and is it the factory antitheft light that blinking

The security, antitheft or lock picture/icon is a visual indication that something in the car's antitheft system is failing. In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM (Theft Deterrent Module). These 3 parts are in CONSTANT communication. If the key is in the ignition, then these parts are sending signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, the car misinterprets this as an attempt at theft and goes into antitheft mode. The car thinks its being stolen or hotwired because it is not getting that signal from YOUR specific key. This is why the security light turns on and shuts down your vehicle. This link explains it pretty well.
http://vatspasslockpasskeysecurityhelp.yolasite.com/

The theft light is a visual indication that something in the car's antitheft system is failing. In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM (Theft Deterrent Module). These 3 parts are in CONSTANT communication. If the key is in the ignition, then these parts are sending signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, the car misinterperates this as an attempt at theft and goes into antitheft mode. The car thinks its being stolen or hot wired because it is not getting that signal from YOUR specific key. This is why the security light turns on and shuts down your vehicle. This link explains it pretty well.
http://vatspasslockpasskeysecurityhelp.yolasite.com/

If the theft light is blinking, there's a fault in the anti-theft (immobilizer) system. There's no way to bypass it. Get the trouble codes read and fix the problem.
Ford PATS Antitheft System Ricks Free Auto Repair Advice

The security, antitheft, or passlock light is a visual indication that something in the car's antitheft system is failing. In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM (Theft Deterrent Module). These 3 parts are in CONSTANT communication. If the key is in the ignition, then these parts are sending signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, the car misinterperates this as an attempt at theft and goes into antitheft mode. The car thinks its being stolen or hotwired because it is not getting that signal from YOUR specific key. This is why the security light turns on and shuts down your vehicle.
This link may help you find ways to bypass this or fix it yourself.
http://vatspasslockpasskeysecurityhelp.yolasite.com/

The security, antitheft, or passlock light is a visual indication that something in the car's antitheft system is failing. In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM (Theft Deterrent Module). These 3 parts are in CONSTANT communication. If the key is in the ignition, then these parts are sending signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, the car misinterperates this as an attempt at theft and goes into antitheft mode. The car thinks its being stolen or hotwired because it is not getting that signal from YOUR specific key. This is why the security light turns on and shuts down your vehicle.
This link may help you find ways to bypass this or fix it yourself.
http://vatspasslockpasskeysecurityhelp.yolasite.com/

if you have theft security problems if you jump start the vechicle it still wont crank.have battery load tested and checked battery could be weak.your current drain can be caused by many things, like radio,faulty power lock, dome light remain on,faulty pcm,faulty alternator,faulty heater blower motor relay.

yes the fast blinking theft light indicates that theft mode is activated. you wont be able to start the vehicle until you have the keys reprogrammed at your local ford dealer.

The theft light blinking fast because there is a problem with the PATS ,(passive antitheft system). You either have a bad chip in one of your keys,PATS transceiver on ignition cylinder or computer. If it is a key you would have to have them programmed into system which requires you to have 2 keys and certain diagnostic equipment to program them into sytem. I would take it to your service provider or someone who has the equipment to do this like a ford or lincoln, mercury dealer.Have a good one!

Something in your anti theft system has failed. The key,transceiver, or module. The only way to find out is to run a diag on that circuit. You will need special tester.