Delta Android Keysystem Guide

Delta Android key system a verification process used to activate the Delta Executor

// 4. Modify response (e.g., store alias mapping) if (status.isOk()) cacheAlias(keyAlias, *metadata); delta android keysystem

• Requires TEE support for versioned master key (not all devices)
• No standardized remote attestation for rotated keys (custom extension needed)
• Overhead of policy evaluation (~1–2ms per operation)

Delta generation (build server):

• Deriving keys solely from predictable inputs (timestamps alone) — always include randomness.
• Storing master key material outside Keystore.
• Skipping integrity checks or AEAD — use AES-GCM or ChaCha20-Poly1305.
• Over-rotating without plan — causes performance/complexity issues.

• HKDF-SHA256: good default. Use 32-byte output for AES-256.
• PBKDF2-HMAC-SHA256: use high iteration count if deriving from low-entropy input (but avoid for master-key derivation when Keystore can provide entropy).
• Salt: unique per derived key (use deltaInput + random nonce).
• Associated data: include metadata (file ID, owner ID) in AEAD to bind context.

Copy and Activate

: Once the tasks are finished, the "Unlock Content" button will turn green. Tap it to generate your unique key, copy it, and paste it back into the Delta app's key box to activate full features. Key Features and Benefits Delta Android key system a verification process used