# Uniquness of identity attributes
**URL:** https://hub.mender.io/t/uniquness-of-identity-attributes/4608
**Category:** General Discussions
**Tags:** identity
**Created:** [February 11, 2022, 5:22pm UTC](https://hub.mender.io/t/uniquness-of-identity-attributes/4608 "2022-02-11T17:22:09Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Sven\_DS](https://hub.mender.io/u/Sven_DS)
#### Post date: [February 11, 2022, 5:22pm UTC](https://hub.mender.io/t/uniquness-of-identity-attributes/4608/1 "2022-02-11T17:22:10Z")
Hi guys,
I have a question regarding the uniquness of identity attributes. I had read [https://docs.mender.io/overview/identity](https://docs.mender.io/overview/identity) and [https://docs.mender.io/api/#management-api-device-authentication-schemas-identitydata](https://docs.mender.io/api/#management-api-device-authentication-schemas-identitydata).
In [https://docs.mender.io/overview/identity](https://docs.mender.io/overview/identity) you write possible device identity attributes can be “_all pieces of data that: … form a 1:1 relationship with the device_”. This would mean that each value of each device identity attribute (of maybe many attributes) is different on each device. And that would make it **impossible** to use a “device type id” as device identity attribute beside the MAC address because there may be thousands of devices with that “device type id” (where a device is a physical instance of a device type).
On the other hand you write: “However, Mender imposes the following requirements for device identities: _The combination of the attribute values must be unique to each device_, so that identities are not ambiguous when deploying software.” This would imply that it is **possible** to use a “device type id” as device identity attribute in addition to the MAC address because the MAC address makes the “overall” identity unique.
All of this together is a bit confusing. Because if the first one is correct, the second one will also be correct - always and forever. So if the first is correct, the second becomes redundant and unnecessary.
Thanks
Sven
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### Author:  [@Sven\_DS](https://hub.mender.io/u/Sven_DS)
#### Post date: [February 16, 2022, 2:39pm UTC](https://hub.mender.io/t/uniquness-of-identity-attributes/4608/2 "2022-02-16T14:39:26Z")
I answered the question myself with a test. The statement “all pieces of data that: form a 1:1 relationship with the device” is misleading. The statement “The combination of the attribute values must be unique to each device …” is right.