ASL/ENCRYPTED-BLOCKS/1 -- Encrypted Block Storage Across Domains

Status: Draft Owner: Architecture Version: 0.1.0 SoT: No Last Updated: 2025-01-17 Tags: [encryption, blocks, federation, storage]

Document ID: ASL/ENCRYPTED-BLOCKS/1 Layer: L2 -- Encrypted storage semantics (no transport)

Depends on (normative):

ASL-STORE-INDEX
ASL/FEDERATION/1
ASL/LOG/1

Informative references:

ASL/DOMAIN-MODEL/1
ASL/POLICY-HASH/1

0. Conventions

The key words MUST, MUST NOT, REQUIRED, SHOULD, and MAY are to be interpreted as in RFC 2119.

ASL/ENCRYPTED-BLOCKS/1 defines semantics for storing encrypted blocks across domains. It does not define encryption algorithms, key management, or transport.

1. Purpose

This document defines how encrypted blocks may be stored in a foreign domain without transferring semantic authority or decryption capability.

2. Core Principle (Normative)

A domain MAY store encrypted blocks for another domain, but MUST NOT assert semantic meaning for those bytes.

Meaning is owned by the domain that holds the decryption keys and index entries.

3. Encryption Model (Normative)

3.1 Block Encryption

Before sealing, a block MAY be encrypted:

plaintext_block
  -> encrypt(K)
  -> ciphertext_block
  -> BlockID = H(ciphertext_block)

Rules:

Encryption occurs before sealing.
BlockID is computed over ciphertext bytes.
Deterministic encryption is NOT required.

3.2 Key Ownership

Encryption keys are owned by the originating domain.
Keys MUST NOT be federated or embedded in index metadata.
Decryption metadata MUST remain local to the originating domain.

4. Foreign Domain Storage (Normative)

A foreign domain storing encrypted blocks:

Treats ciphertext blocks as opaque bytes.
MAY retain or GC blocks under its local policy.
MUST NOT create semantic index entries for those blocks.

5. Originating Domain References (Normative)

The originating domain:

Maintains index entries referencing the ciphertext BlockID.
Applies normal visibility, log, and snapshot rules.
Uses local decryption metadata to materialize plaintext.

6. Cross-Domain References (Informative)

Two references are distinct:

Storage reference: foreign domain stores ciphertext blocks.
Semantic reference: originating domain records artifact visibility and meaning.

Foreign storage does not imply federation of semantics.

7. Non-Goals

ASL/ENCRYPTED-BLOCKS/1 does not define:

Key exchange or key discovery
Encryption algorithm choices
Transport or replication protocols
Storage layout or block packing rules

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