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STMicroelectronics Launches ST25TA-E Authentication NFC Tag

05 April 2024   |   Opinion

One of the leading NFC chip manufacturers, STMicroelectronics, has announced a new authentication grade NFC chip - the ST25TA-E. This could be big news for the authentication NFC tag market and their offering presents a different approach to current market leader - NXP's NTAG424. Here's why. 

Symmetric vs Asymmetric Encryption

NTAG424's symmetric encryption

As anyone who's using authentication NFC tags will know, the current market leader in this space is NXP with their NTAG424 chip. NXP also make other authentication chips - the NTAG223 and NTAG224 - but the NTAG424, which was released earlier, maintains substantial market share. 

The NTAG424 uses symmetric encryption to provide anti-counterfeit protection. This means that when we (or our customers) encode the NTAG424 chip, we store a secret key onto the memory of the chip. The NTAG424 uses this key to generate a unique code on each scan using the scan counter which can be dynamically included in the URL. A server - such as ixkio tag management platform - also stores a copy of this key and using the same scan count undergoes the same process to generate the unique code. If the unique codes match, then the tag is authentic. 

An important part of this configuration is that the secret key must be just that - secret. The key stored on the NFC chip cannot be visible to anyone but the same key is also stored on a server to verify the tag. This 'symmetric' encryption process means that the key cannot be stored on a blockchain as such visibility would mean that the tag itself could be copied and recreated - defeating the whole purpose of the authentication tag. 

ST25TA-E's assymmetric encryption

STMicro's newly released ST25TA-E chip is offering assymetric encryption. This means that there's a private key - which is securely stored on the chip - and a public key - which anyone can view. As the public key is able to be visible, it's possible to store this public key on a blockchain for general visibility. 

Why blockchain storage of NFC authentication keys is important 

There's a few reasons but it generally comes down to two aspects : the longer term availability of the keys and the security of the keys. 

Long term availability

Private keys need to be stored on a private server. The argument is that storing the public keys on a blockchain will provide longer term security over their availability. They will be stored as a permanent record and can be accessed and stored by anyone anywhere. Something that isn't possible with private keys. 


The private key stored on a server is always potentially vulnerable to being compromised. The benefit of having a public key is that there's no concern over the visibilty of the key. 

Why assymetric doesn't solve all the issues, yet. 

However, the implementation of this is not so simple at the moment.

For universal use of an NFC tag, the tags need to be encoded with a URL or web link. In the current market, this would link to a 'Web 2.0' which, simply, means a domain name related to a fixed server. In other words, the NFC tags have to link somewhere and that somewhere is always currently a private server on a domain name. The owner of that domain name therefore controls the destination of the NFC tag. 

Therefore, while you can have open public keys behind the NFC tag scan, the tag scan itself does not benefit from the immutability and transparency of using a blockchain. If the domain vanishes, the tag stops working. 

In the longer term, Web 2.0 might be replaced with Web 3.0 browsers where content and applications are not tied to a single domain / server. But these aren't available right now and it will be a very long time before they are widely used and available. 

Clearly, it's not absolutely necessary to use a URL link on the tags. Access and usage of the tags can be via an App only but losing the frictionless URL 'anyone can just scan' nature of an NFC tag loses - in our opinion - a critical benefit of the technology itself. 

When will the ST25TA-E be available ?

STMicroelectronics have stated that the chip will be available in mass production by August 2024. Seritag will conduct extensive testing on the pre-production chips so that we can provide help, support and advice as we do with all products. 

Will ixkio support the ST25TA-E chip ? 

Of course. Our ixkio tag management platform can work with any of the current EM, STMicro or NXP chips. We intend that ixkio will provide full support for the ST25TA-E including storage of keys on the blockchain. We are excited by all developments in this market space and are keen to allow our customers to use this with our powerful tag management platform to it's maximum feature set. 

Will the ST25TA-E change the market for authentication chips ?

This remains to be seen. There are an increasing number of customers starting to use NFC tags for DDP (digital product passports). The longer term aim of DDP is that product data - or digital twin data - would be stored on the blockchain. The logic is that product related data is open and accessible to all for the lifetime of the product. 

By storing the tag keys also on the blockchain then clearly the general logic is that the entire tag content - and ability to access that content -  is also openly available for the lifetime of the tag and not connected to the a single server/company. However, as discussed earlier, due to the nature of frictionless 'app-free' tag scanning, we aren't completely convinced of the benefits - yet. 

What we can be sure of - if we consider this chip to help our customers acheive their project goals - it will be on our shelves as fast as we can offer it !

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