When Nightfall AI fits
- You want a mature, centrally managed DLP platform with broad SaaS integration coverage and an auditable detection record.
- Your security team prefers server-side detection and centralised policy management over per-device controls.
- You need data discovery and classification across many cloud applications, not only the AI-prompt path.
When Locke fits
- You want detection to run entirely on the device, with no prompt content evaluated by an external service.
- Zero-knowledge is a hard requirement: the privacy layer itself should never see your data.
- You want a low-cost entry point: the Locke Early Access desktop app, free for one person.
Side-by-side
| Dimension | Locke | Nightfall AI |
|---|---|---|
| Where detection runs | Entirely on the device, before any network call. | Centralised, AI-native detection across integrated apps and traffic. |
| Trust model | Zero-knowledge: the vendor never sees prompt content. | Content is evaluated by the platform to enforce policy. |
| Primary scope | Sensitive data in AI prompts, masked before it leaves the device. | Broad data security and DLP across SaaS, with AI controls added. |
| Entry point | Locke Free costs nothing (Early Access); Teams starts at $14.99 per seat a month. | Commercial platform. Contact vendor for current pricing. |
| Best for | Local-first, zero-knowledge control over AI prompts. | Centralised, AI-native DLP across a cloud-app estate. |
Bottom line
Nightfall AI is a capable, broad data-security platform with strong centralised detection. Locke is narrower and deliberately local: detection runs on the device, the privacy layer never sees your data, and the entry point is free. For centralised cloud DLP, Nightfall is a serious option. If local-first and zero-knowledge are non-negotiable, look at Locke. Compare current capabilities with the vendor before deciding.
