# kaal:position:2026-08-26-005

**Affirmed position.** Encryption at rest does not establish user-held state when the service provider controls the keys. Hofmann and Truong show why. In their analysis of end-to-end encrypted cloud storage, provider-held keys supply no protection once the provider is compromised. The relevant alternative encrypts files under keys managed by the user and evaluates confidentiality against a server with full access to its own infrastructure. This moves custody from a promise about data location to a test of decryption authority.

The evidence is narrower than the general claim. The study concerns cloud storage, not agent working memory, and it documents flaws even in systems marketed as zero knowledge. User-managed keys can still fail through protocol defects, malicious client delivery, weak credentials, or metadata leakage. Those limits sharpen the classification. State is not user-held merely because ciphertext sits behind an ownership label. It is user-held only when the operator lacks the capability to recover the working contents without the user's participation. A credible system should test that condition against a compromised provider, not against its marketing description.

**Status.** affirmed  **Published.** 2026-08-26

**Holds when.**

- The response is limited to the exact full-text propositions and the one mapped Kaal claim.
- External evidence level: peer-reviewed ACM CCS 2024 conference paper with complete public full text.
- Mapping review tier: independent substantive scholarly-growth extension.
- The paper studies cloud-storage confidentiality and integrity, not AI agent runtimes or volatile working memory.
- User-managed keys do not by themselves establish a secure design because protocol defects, malicious client delivery, and weak credentials can expose plaintext.
- The provider may still learn metadata even when file contents remain confidential.
- The study evaluates five named providers and does not prove security or insecurity for every end-to-end encrypted service.

**Current debate.** End-to-End Encrypted Cloud Storage in the Wild: A Broken Ecosystem: https://doi.org/10.1145/3658644.3690309

**Extends.** kaal:claim:7314479-005: https://wulfkaal.github.io/claims/7314479-005

**Scholarly basis.** Wulf A. Kaal, Institutional Requirements for Sovereign Local Agent Runtimes (2026). SSRN: https://ssrn.com/abstract=7314479

**Source PDF sha256.** `debace24a155ae924a155b1fafe98856d98cf83689feff2f87a32f1c06171ce6`

**Evidence level.** peer-reviewed ACM CCS 2024 conference paper with complete public full text

**Mapping review tier.** independent substantive scholarly-growth extension

**Mapping confidence.** 0.98  **Mapping ambiguous.** false

**Topics.** ai-and-agents, institutional-design, decentralization, end-to-end-encryption, cloud-storage, key-custody, evidence-provenance

**Provenance.** Affirmed in kaal-review:2026-08-26:scholarly-growth-7314479-005-reviewed-v1 at https://wulfkaal.github.io/positions/by-claim/7314479-005.html.

**Record type.** This is a dated commentary position that extends a scholarly corpus claim. It is not a verbatim claim extracted from the paper.

**Canonical form.** This markdown file is the canonical hashed representation of the position.