CMEK, data retention, and ZDR
Why a workspace with a key retains data, what that means for ZDR, and what Anthropic can preserve outside your key.
On Claude Platform, customer-managed encryption keys (CMEK) and zero data retention (ZDR) can't share a workspace. On Claude Enterprise, an organization can use CMEK and ZDR together, but it then can't turn on artifacts.
A key needs a workspace that retains data
CMEK encrypts stored data, and under ZDR on Claude Platform, Anthropic doesn't store your prompts or responses. So you can attach a key only to a workspace with Standard data retention (30 days).
After you attach a key, you can't turn off data retention for that workspace. To return to ZDR, create a new workspace and move your traffic to it.
In a ZDR organization
A ZDR organization on Claude Platform can use CMEK. You switch one workspace to Standard data retention, accept the data retention terms, and attach your key to it. The workspace you switch can't be the default workspace, whose retention follows the organization's. Your other workspaces keep ZDR.
Choose your setup page and follow its attach step.
Limited preservation outside your key
In three narrow cases, Anthropic may preserve specific records under Anthropic-managed encryption:
- Where Anthropic is required by law to retain records (for example, material reported to NCMEC under 18 U.S.C. § 2258A)
- Exigent risk of serious harm (for example, CBRNE weapons development, offensive cyberattacks, or imminent threats of violence)
- Violations of Section D.4 of Anthropic's Commercial Terms of Service or equivalent terms in a customer's other applicable agreement with Anthropic
Outside of CSAM screening, preservation requires a human reviewer's explicit decision and follows Anthropic's retention policy for commercial data. For every instance of preservation, a corresponding Compliance API Activity Feed event is generated with a reason code conveying the purpose of the preservation. See CMEK content preservation for details. Safety screening metadata is retained under Anthropic-managed encryption and remains readable after key revocation. These are records derived from Anthropic's automated safety scans, such as pattern identifiers and match indicators, not conversation content.
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