Final Merge#791
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…rary and embedded manifests. Specific changes: - Integrated `com.github.contentauth:c2pa-android` library to handle Content Authenticity (C2PA). - Removed `rust-c2pa-ffi` directory and associated JNI wrappers, Cargo configurations, and custom Gradle build tasks. - Implemented `ProofmodeC2paManager` to manage embedded manifest signing using software-backed EC keys and self-signed X.509 certificate chains via BouncyCastle. - Updated `CameraViewModel` to embed C2PA manifests directly into media files (JPEG/MP4) immediately after capture, replacing the previous sidecar approach. - Removed "sidecar" manifest logic (separate `.c2pa.json` files) across the application, including `C2paHelper`, `WebDavConduit`, and `FileCleanupHelper`. - Removed `C2paKeyStore` and associated security migration logic in favor of the new certificate management in `ProofmodeC2paManager`. - Added BouncyCastle dependencies (`bcprov-jdk18on`, `bcpkix-jdk18on`) to support cryptographic operations for manifest signing. - Simplified `SaveApp` and `HomeActivity` initialization logic to use the new manager.
Specific changes: **ProofMode Integration** - Added `ProofCompanionGenerator` to create verification metadata, including `.proof.json`, PGP signatures (`.asc`), and OpenTimestamps (`.ots`) files. - Implemented PGP key pair generation and storage using Bouncy Castle, supporting detached signatures for both media and metadata. - Added logic to populate proof JSON with ProofMode v1 fields, including hardware details and EXIF-derived location data. - Integrated OpenTimestamps (OTS) to submit media hashes to a remote calendar and store the resulting timestamp proof. **Upload & Infrastructure** - Updated `WebDavConduit` to automatically detect and upload companion files during the media upload process. - Added `getProofFiles()` to the base `Conduit` class to facilitate metadata generation at upload time. - Added `org.bouncycastle:bcpg-jdk18on` dependency for OpenPGP support. - Initialized `ProofCompanionGenerator` in the application class to ensure PGP keys are ready for use.
… and improve metadata reliability.
Specific changes:
- **C2PA Security & Performance**:
- Implemented encryption-at-rest for C2PA private keys using AES-256-GCM with wrap keys stored in Android Keystore.
- Optimized signing workflow to use `FileStream`, preventing large files from being loaded entirely into memory.
- Added a post-sign verification step to ensure C2PA manifests are correctly embedded before modifying original files.
- Updated certificate profiles to use `id-kp-documentSigning` (RFC 9336) and improved serial number generation.
- **Proof Generation & PGP**:
- Decoupled proof generation into local capture-time signing (PGP/JSON) and upload-time network tasks (OTS).
- Migrated PGP keys from RSA to Ed25519 and implemented streaming PGP signing.
- Added Android Keystore-backed encryption for the PGP secret key ring.
- Implemented a persistent retry queue (`pending_ots.txt`) for OpenTimestamps submissions to handle network failures.
- **Metadata & EXIF**:
- Enhanced EXIF metadata with UTC offset tags (`TAG_OFFSET_TIME`) for forensic timestamp accuracy.
- Improved `CellInfo` collection by filtering out `Int.MAX_VALUE` sentinel values.
- Standardized capture time extraction using `ExifInterface` for consistency between proof JSON and C2PA manifests.
- **Storage & Cleanup**:
- Updated `WebDavConduit` to recursively delete local proof companion files after successful uploads.
- Modified `Conduit.getProofFiles` to be a suspend function to support asynchronous OTS preparation.
Specific changes:
- Transitioned from software-only signing to a two-key design to ensure media content is signed within the Android Keystore TEE.
- Implemented `SIGNING_KEY_ALIAS` for a persistent EC P-256 key in secure hardware, ensuring private key material never leaves the TEE.
- Retained a software-based CA key (encrypted at rest via AES-256-GCM) used solely to sign leaf certificates that carry the hardware public key.
- Updated `embedProof` to use `Signer.withCallback`, bypassing issues with `KeyStoreSigner` by performing manual signing via `Signature.getInstance("SHA256withECDSA")`.
- Added `generateKeystoreSigningKey` and `keystoreSign` to manage the hardware key lifecycle and signing operations.
- Refactored C2PA assertion JSON generation (Actions, CreativeWork, Location, Network) for better performance and reduced string allocations.
- Enhanced error handling and recovery for Keystore wrap-key loss scenarios.
Specific changes: Proofmode/C2PA: - Implement `certMatchesKeystoreKey` to verify that on-disk certificates match the current Android Keystore signing key, preventing the use of stale or orphaned cert files. - Update `ensureC2paState` to trigger a full state regeneration if a certificate-key mismatch is detected. - Explicitly use the "AndroidKeyStoreBCWorkaround" provider for ECDSA signatures to ensure consistent dispatch to hardware-backed Keystore across different OEM builds. OpenTimestamps: - Introduce a cap of 500 entries (`OTS_QUEUE_MAX`) for the pending OTS hash queue. - Implement an eviction policy in `enqueuePendingOts` to drop the oldest entries when the limit is reached, ensuring bounded storage usage.
Specific changes: - Replaced `SimpleDateFormat` with thread-safe `java.time.DateTimeFormatter` and `Instant` across `ProofmodeC2paManager` and `ProofCompanionGenerator` to ensure safety during concurrent coroutine execution. - Implemented `ensureUsableSigningKey` in `ProofmodeC2paManager` to perform a test signature, allowing the system to detect and regenerate stale or unusable Keystore keys following app upgrades. - Enhanced `ProofmodeC2paManager.embedProof` to ensure partial temporary files are deleted if an exception occurs during the signing process. - Refactored PEM certificate parsing in `certMatchesKeystoreKey` for better readability and reliability. - Updated `enqueuePendingOts` in `ProofCompanionGenerator` with thread synchronization and duplicate entry prevention. - Refined the OTS queue management to consistently bound storage by dropping oldest entries when reaching the maximum limit. - Updated EXIF metadata parsing to use `java.time` APIs for consistency with the rest of the signing pipeline.
- Refactored `observeBySubmission` and `observeByArchive` to use a simple `id ASC` sort order, removing complex status-based prioritization logic. - Updated `getQueueWithErrorsLast` to sort by `id ASC` instead of `id DESC` for more predictable queue processing.
Specific changes: - Updated `SettingsScreen` and `C2paScreen` to use new Proofmode-specific string resources for titles, summaries, and descriptions. - Updated introductory text and links in `strings.xml` to refer to Proofmode and point to `proofmode.org` instead of `c2pa.org`. - Added new string resources for Proofmode branding while maintaining compatibility for localization. - Updated the "Learn More" URL for content authenticity to point to the Proofmode website.
- Drop support for `armeabi-v7a` as all supported devices for `minSdk 29` (Android 10) use 64-bit hardware. - Move `ndk` configuration block to `defaultConfig` to ensure consistent ABI filtering across all build variants.
- Add a check for the existence of the `proof_companions` directory before attempting to prepare files for upload. - Return an empty list if the directory is missing to support gallery imports, which do not generate proof companion files.
… file generation.
Specific changes:
**Proof Generation & Metadata:**
- Expanded `ProofCompanionGenerator` to generate `.csv` proof files and corresponding PGP signatures (`.csv.asc`) alongside existing JSON proofs.
- Added a dynamically generated `HowToVerifyProofData.txt` to the proof bundle with instructions for manual GPG, OpenTimestamps, and Play Integrity verification.
- Refactored metadata extraction into `buildProofFields` to include richer device and network information (e.g., Brand, Model, Network Type, IPv4/IPv6, CellInfo) directly from `CaptureMetadata`.
- Updated `CameraViewModel` to pass live capture metadata to the proof generator, ensuring sensor and device fields are preserved without relying solely on EXIF.
**Google Play Integrity (GST):**
- Introduced `SafetyNetHelper` with flavor-specific implementations:
- **GMS:** Requests a Play Integrity token (GST) using a nonce derived from the media hash and saves it to a `.gst` file.
- **FOSS:** Provides a no-op stub for environments without Google Mobile Services.
- Added `com.google.android.play:integrity` dependency to the GMS build configuration.
**Networking & Utilities:**
- Updated OpenTimestamps (OTS) submission to use `application/octet-stream` for raw hash uploads.
- Implemented CSV escaping logic to handle special characters and line breaks in metadata fields.
- Included the new `.csv`, `.gst`, and instruction files in the list of companions prepared for upload.
…-on-new-requirements [WIP] Implement Play Integrity attestation and expand proof companion…
![github-advanced-security[bot]](https://avatars.githubusercontent.com/in/57789?s=60&v=4){kind=small}
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detekt found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.
- Modified metadata upload logic to throw an exception if all retries fail, instead of logging a non-fatal error. - Ensures that failure to upload metadata triggers a job retry, where `isAlreadyUploaded()` will skip existing content and re-attempt only the metadata upload.
prathieshna
marked this pull request as ready for review
July 12, 2026 15:14
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