It depends on the type of RFID system you are using. Passive low-frequency (LF), high-frequency (HF) and ultrahigh-frequency (UHF) solutions, as well as active systems, all have a variety of protocols that govern how tags and readers communicate. But generally speaking, the answer is yes, you can usually erase or “zero out” data (that is, replace a serial number with all zeros).
With passive UHF tags based on EPCglobal‘s second-generation air-interface protocol, there are several types of memory: tag ID memory, Electronic Product Code (EPC) memory and user memory. Tag ID memory is usually written to a tag when the microchip is manufactured, and is not alterable. EPC memory can usually be written and locked so that it can not be changed, but if you write the EPC to your own tags, you can choose either not to lock them, or to allow them to be unlocked. And the same is true of user memory—you can leave it unlocked, lock it so that it can be unlocked with a password, or permanently lock it so that it can’t be changed.
—Mark Roberti, Founder and Editor, RFID Journal
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