HaLo chips include ISO 7816 and ISO 14443 interfaces. See Overview for more detail on these interfaces.

HaLos generate and store secp256k1 keypairs that can be used to sign messages and transactions on- or off-chain. By design, HaLos do not expose any interface for the extraction, deletion or replacement of these keypairs.

Form Factors

Available in several standard form factors including:

Round, 27mm diameter tag
CR80 card form factors
Rectangular 30x50mmm tag
Wrist bracelet tag

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Custom form factors and printing are available from Arx Research with minimum order volumes. Contact sales@arx.org for more information.

Application Durability

All form factors are machine washable and driable, however, note that foil or printed features will wear off over time due to abrasion. HaLo chips have an expected longevity of 10+ years depending on the frequency of use.

The internal silicon for HaLos is rated for temperatures from -25° to 85°, however, the printed, foil and plastic elements of the HaLo may discolor, wear off, fade or warp at high temperatures within this range.

HaLos can be adhered to or embedded within most materials except for metal. See Integration for more details and examples applications.


The open source LibHaLo (opens in a new tab) library adds HaLo-scanning capabilities to mobile, web and desktop applications. See Examples for open source apps that can be used as a starting point for HaLo scanning.


Last updated on March 8, 2024