aosp-security

aosp-security is a skill for Claude Code, Codex from aospbooks/aosp-internal-book. It costs 134 tokens per session (493 once invoked), scanned A, original, Apache-2.0.

A guide to Android security systems, including permission rules, protected key storage, trusted hardware, verified startup, and digital credentials. It also covers protection for media and untrusted code.

In plain words
What is it for?
Use it when working on SELinux, Keystore or KeyMint, hardware-backed attestation, passkeys, digital rights management, or lightweight fault isolation.
Why use it?
It helps explain how Android protects data, verifies software, handles passwords and passkeys, and restricts sensitive operations.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when working on SELinux, Keystore or KeyMint, hardware-backed attestation, passkeys…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aospbooks/aosp-internal-book/security
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add aospbooks/aosp-internal-book --skill security
Clone the repo
git clone --depth 1 https://github.com/aospbooks/aosp-internal-book

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for aosp-security

README.md
[![agentmods](https://agentmods.dev/badge/skills/aospbooks/aosp-internal-book/security.svg)](https://agentmods.dev/skills/aospbooks/aosp-internal-book/security)
Your own site
<a href="https://agentmods.dev/skills/aospbooks/aosp-internal-book/security"><img src="https://agentmods.dev/badge/skills/aospbooks/aosp-internal-book/security.svg" alt="Measured on agentmods" height="20"></a>
Per session 134 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 493 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00134 $0.00493
Opus 5 $0.00067 $0.00246
Sonnet 5 $0.00027 $0.00099
Haiku 4.5 $0.00013 $0.00049

Measured 7d ago against content hash 0b8303f0640e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

aosp-security scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

agents/_content/parts/security/SKILL.md · 35 lines

What it actually says

AOSP Part IX — Security

Trust roots, key storage, credential management, and content protection.

Chapters in this Part

  • 40-security.md — SELinux on Android, Keystore/Keymint, Trusty TEE, gatekeeper/weaver, AVB, dm-verity, hardware-backed attestation
  • 41-credential-manager.md — CredentialManagerService, credential providers, passkeys/FIDO2, password and autofill integration, digital credentials
  • 42-drm.md — MediaDrm framework, Widevine L1/L2/L3, OEMCrypto, license acquisition, secure decoder/display path
  • 43-lfi-sandbox.md — Lightweight Fault Isolation: memory-safe in-process sandboxing for untrusted code (software codecs) without a separate process; the external/lfi verifier and runtime, the Soong LFI toolchain, and the libapexcodecs/codec2 integration

When to load which chapter

  • Question mentions SELinux, Keystore, Keymint, Trusty, gatekeeper, weaver, AVB, attestation → 40-security.md
  • Question mentions Credential Manager, passkeys, FIDO2, autofill, digital credentials → 41-credential-manager.md
  • Question mentions MediaDrm, Widevine, OEMCrypto, secure decoder, license server → 42-drm.md
  • Question mentions LFI, lightweight fault isolation, in-process sandboxing, sandboxed software codec → 43-lfi-sandbox.md
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago First seen · 35 lines · 134 tokens per session scan A 0b8303f0640e

Subscribe to this mod's changes

aosp-security is a skill published in the GitHub repository aospbooks/aosp-internal-book (131 stars, last pushed 8d ago), licensed Apache-2.0. It adds 134 tokens to every session and 493 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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