Skip to content

docs: Define supported threat model #227

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
BenWestgate wants to merge 2 commits into
base: 211-bound-privacy-security-claims
Choose a base branch
from
Open

docs: Define supported threat model #227

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4e02e72
docs: Define supported threat model
BenWestgate Sep 21, 2026
c8b005a
docs: Note unsigned delivery gap
BenWestgate Oct 6, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,8 @@ For a discussion on the pros and cons of using CipherStick, refer to the [detail

On this branch, CipherStick installs and configures Bitcoin Core, guides Persistent Storage setup, provides passphrase practice, and installs the pinned `python-codex32` application for codex32 backup and recovery. Clone/Backup actions and the removed legacy `bails-wallet` implementation are not supported recovery interfaces.

See the [CipherStick threat model](docs/THREAT_MODEL.md) for the installer-specific trust boundaries and non-goals.

## Source Code Headers

Every file containing source code must include copyright and license
Expand Down
17 changes: 17 additions & 0 deletions docs/THREAT_MODEL.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
# CipherStick Threat Model

CipherStick's supported runtime is a Tails installer for Bitcoin Core, Persistent Storage setup guidance, passphrase practice, and the pinned `python-codex32` application for codex32 backup and recovery. CipherStick itself does not manage wallet keys or make wallet-security decisions; `python-codex32` and Bitcoin Core do.

## Boundaries CipherStick owns

- **Installer delivery:** downloaded CipherStick code can modify Persistent Storage. Releases and updates must identify and authenticate the exact code before it runs. Current repository clones do not yet satisfy this boundary; signed-release work is tracked by #206.
- **Bitcoin Core installation:** CipherStick chooses download locations, accepted signers, and release metadata. Its verification must reject an artifact, signer set, or metadata value that does not meet the local policy.
- **Persistent Storage changes:** CipherStick writes software and configuration beneath the unlocked persistence mount. It must use intended paths and permissions and must not silently copy wallet, recovery, log, or identifying data.
- **Pinned codex32 checkout:** CipherStick fetches an exact `python-codex32` revision and repairs a checkout whose files differ from it. This check catches corruption and accidental changes. It does not protect against an attacker who can already write Persistent Storage, since that attacker can also change CipherStick's own scripts.
- **Handoff guidance:** a recipient should start with their own Tails installation and Persistent Storage. Any transferred data must be selected explicitly by the person performing the handoff.

## Assumptions and non-goals

CipherStick relies on Tails for operating-system isolation, encryption, and Tor routing, and on Bitcoin Core for consensus validation and wallet behavior. It does not claim to protect against compromised hardware or firmware, an attacker controlling an unlocked Tails session, loss of required secrets, coercion, transaction-graph analysis, malicious counterparties, or all traffic correlation.

The installer can reduce the risk introduced by its own automation; it cannot remove risks inherited from Tails, Bitcoin Core, the user's hardware, or the user's operational choices. Planned features are outside this threat model until they are implemented, tested, and reviewed.
Loading