# Identifying Users
source: https://developer.mastercard.com/open-finance-europe/documentation/licensed/aiia-enterprise/connect/identifying-users/index.md

End-users are identified using a pseudonym called `userHash`. The `userHash` is generated by the client.

Here are some suggestions on how to generate the `userHash`:

* The identifier should not make it possible to trace directly back to the user (e.g. by calculating a hash of the client's internal ID of the user)
* The link between users and user hashes should only exist in the client's systems. In this way, users can not be identified directly in Aiia Enterprise

This strategy ensures Aiia Enterprise holds the least possible amount of end-user personal information. The `userHash` allows clients to contact Aiia Enterprise in case of issues and provide the `userHash` to make it possible to locate information about the exact end-user in the logs stored by Aiia Enterprise.
Note: Individual requests to the API can be identified by [Correlation IDs](https://developer.mastercard.com/open-finance-europe/documentation/licensed/aiia-enterprise/api-basics/advanced-topics/index.md).