Sharepoint IRM vs Azure AIP
SharePoint IRM vs Azure AIP
Both the approaches SharePoint IRM and Azure AIP encrypt the document so that unauthorized or accidental share of files does not result in a data breach. However SharePoint IRM does not restrict SharePoint capabilities like Document preview, Open in the browser, and SharePoint search and the document is encrypted the moment user downloads the file on a local machine.
With Azure AIP, using conditions like sensitive types, the document can get encrypted and protected, and if such documents get uploaded in SharePoint. SharePoint online will not be able to access document contents within the file so searching for file content is not possible, document previews and Open in the browser for such files will not work.
Also, SharePoint IRM gets applied a the document library level, where Azure AIP or Office 365 encryption can work based on Smart rules and can identify “Keyword Match” or Sensitive information types like Financial OR PII data and auto label and also encrypt the files.
Related Resources:
Here is some Microsoft documentation on the requested topics:
Set up Information Rights Management (IRM) in SharePoint admin center
https://docs.microsoft.com/en-us/office365/securitycompliance/set-up-irm-in-sp-admin-center
Apply Information Rights Management (IRM) to a list or library
https://docs.microsoft.com/en-us/office365/securitycompliance/apply-irm-to-a-list-or-library
What is Azure Information Protection?
https://docs.microsoft.com/en-us/azure/information-protection/what-is-information-protection