Locke vs Microsoft Purview Information Protection

Microsoft Purview (formerly Azure Information Protection) is a mature DLP and labelling platform built deep into Microsoft 365. It is strong at classifying and protecting documents, email, Teams and SharePoint, and its AI Hub now adds AI controls. Its reach stops at the Microsoft 365 boundary. A prompt typed into ChatGPT or Claude sits outside it, and so does a labelled Word document pasted into another vendor's AI tool.

When Microsoft Purview Information Protection fits

  • Your organisation is deeply invested in Microsoft 365 and needs sensitivity labelling, encryption, and rights management across email, Teams, SharePoint, and Office documents.
  • You need centralised policy management, compliance manager dashboards, and eDiscovery that spans the full Microsoft 365 estate.
  • Your primary AI governance concern is Microsoft Copilot. Purview's AI Hub provides prompt auditing and policy enforcement within the M365 boundary.

When Locke fits

  • Employees use browser-based AI tools outside the Microsoft 365 boundary, such as ChatGPT, Claude, Gemini, Grok and Perplexity, where Purview has no reach.
  • You need a control that acts at the moment of composition, before text is submitted, rather than after the document is classified.
  • You want a zero-knowledge control: no prompt content is logged by the privacy vendor, unlike Purview's audit logs which capture prompt text.

Side-by-side

DimensionLockeMicrosoft Purview
Coverage of non-Microsoft AI toolsWorks on supported browser-based AI chats: ChatGPT, Claude, Gemini and others.Limited to Microsoft 365 apps and Copilot; no coverage of competitor AI tools.
Where controls operateOn the device, inside the browser, at the moment of composition.At the Microsoft 365 layer: documents, email, Teams, SharePoint.
Sensitive-data visibility to the vendorZero-knowledge: Sonomos never sees prompt content.Purview audit logs capture prompt text and policy matches, visible to your admin.
Rollout effortPer-user, on-device Locke Early Access install: days to deploy at scale.Deep integration with M365 tenant configuration: weeks to months.
Best forPreventing sensitive data from reaching any browser-based AI tool.Classifying, labelling, and protecting documents and communications within M365.

Bottom line

Purview and Locke protect different surfaces and work well together. Purview governs the Microsoft 365 estate: documents, email, Teams and Copilot. Locke screens the moment someone uses another AI tool it covers, such as pasting a labelled Word document into ChatGPT.

Download LockeSee the Locke demoSee pricingTalk to the team

Further reading