base on Home to the Signal Protocol as well as other cryptographic primitives which make Signal possible. # Overview libsignal contains platform-agnostic APIs used by the official Signal clients and servers, exposed as a Java, Swift, or TypeScript library. The underlying implementations are written in Rust: - libsignal-protocol: Implements the Signal protocol, including the [Double Ratchet algorithm][]. A replacement for [libsignal-protocol-java][] and [libsignal-metadata-java][]. - signal-crypto: Cryptographic primitives such as AES-GCM. We use [RustCrypto][]'s where we can but sometimes have differing needs. - device-transfer: Support logic for Signal's device-to-device transfer feature. - attest: Functionality for remote attestation of [SGX enclaves][] and server-side [HSMs][]. - zkgroup: Functionality for [zero-knowledge groups][] and related features available in Signal. - zkcredential: An abstraction for the sort of zero-knowledge credentials used by zkgroup, based on the paper "[The Signal Private Group System][]" by Chase, Perrin, and Zaverucha. - poksho: Utilities for implementing zero-knowledge proofs (such as those used by zkgroup); stands for "proof-of-knowledge, stateful-hash-object". - account-keys: Functionality for consistently using [PINs][] as passwords in Signal's Secure Value Recovery system, as well as other account-wide key operations. - usernames: Functionality for username generation, hashing, and proofs. - media: Utilities for manipulating media. This repository is used by the Signal client apps ([Android][], [iOS][], and [Desktop][]) as well as server-side. Use outside of Signal is unsupported. In particular, the products of this repository are the Java, Swift, and TypeScript libraries that wrap the underlying Rust implementations. All APIs and implementations are subject to change without notice, as are the JNI, C, and Node add-on "bridge" layers. However, backwards-incompatible changes to the Java, Swift, TypeScript, and non-bridge Rust APIs will be reflected in the version number on a best-effort basis, including increases to the minimum supported tools versions. [Double Ratchet algorithm]: https://signal.org/docs/ [libsignal-protocol-java]: https://github.com/signalapp/libsignal-protocol-java [libsignal-metadata-java]: https://github.com/signalapp/libsignal-metadata-java [RustCrypto]: https://github.com/RustCrypto [Noise protocol]: http://noiseprotocol.org/ [SGX enclaves]: https://www.intel.com/content/www/us/en/architecture-and-technology/software-guard-extensions.html [HSMs]: https://en.wikipedia.org/wiki/Hardware_security_module [zero-knowledge groups]: https://signal.org/blog/signal-private-group-system/ [The Signal Private Group System]: https://eprint.iacr.org/2019/1416.pdf [PINs]: https://signal.org/blog/signal-pins/ [Android]: https://github.com/signalapp/Signal-Android [iOS]: https://github.com/signalapp/Signal-iOS [Desktop]: https://github.com/signalapp/Signal-Desktop # Building ### Toolchain Installation To build anything in this repository you must have [Rust](https://rust-lang.org) installed, as well as Clang, libclang, [CMake](https://cmake.org), Make, protoc, and git. #### Linux/Debian On a Debian-like system, you can get these extra dependencies through `apt`: ```shell $ apt-get install clang libclang-dev cmake make protobuf-compiler git ``` #### macOS On macOS, we have a best-effort maintained script to set up the Rust toolchain you can run by: ```shell $ bin/mac_setup.sh ``` ## Rust ### First Build and Test The build currently uses a specific version of the Rust nightly compiler, which will be downloaded automatically by cargo. To build and test the basic protocol libraries: ```shell $ cargo build ... $ cargo test ... ``` ### Additional Rust Tools The basic tools above should get you set up for most libsignal Rust development. Eventually, you may find that you need some additional Rust tools like `cbindgen` to modify the bridges to the client libraries or `taplo` for code formatting. You should always install any Rust tools you need that may affect the build from cargo rather than from your system package manager (e.g. `apt` or `brew`). Package managers sometimes contain outdated versions of these tools that can break the build with incompatibility issues (especially cbindgen). To install the main Rust extra dependencies matching the versions we use, you can run the following commands: ```shell $ cargo +stable install cbindgen cargo-fuzz $ cargo +stable install --version "$(cat ../acknowledgments/cargo-about-version)" --locked cargo-about $ cargo +stable install --version "$(cat ../.taplo-cli-version)" --locked taplo-cli ``` ## Java/Android To build for Android you must install several additional packages including a JDK, the Android NDK/SDK, and add the Android targets to the Rust compiler, using ```rustup target add armv7-linux-androideabi aarch64-linux-android i686-linux-android x86_64-linux-android``` To build the Java/Android ``jar`` and ``aar``, and run the tests: ```shell $ cd java $ ./gradlew test $ ./gradlew build # if you need AAR outputs ``` You can pass `-P debugLevelLogs` to Gradle to build without filtering out debug- and verbose-level logs from Rust. Alternately, a build system using Docker is available: ```shell $ cd java $ make ``` When exposing new APIs to Java, you will need to run `rust/bridge/jni/bin/gen_java_decl.py` in addition to rebuilding. This requires installing the `cbindgen` Rust tool, as detailed above. ### Maven Central Signal publishes Java packages on [Maven Central](https://central.sonatype.org) for its own use, under the names org.signal:libsignal-server, org.signal:libsignal-client, and org.signal:libsignal-android. libsignal-client and libsignal-server contain native libraries for Debian-flavored x86_64 Linux as well as Windows (x86_64) and macOS (x86_64 and arm64). libsignal-android contains native libraries for armeabi-v7a, arm64-v8a, x86, and x86_64 Android. When building for Android you need *both* libsignal-android and libsignal-client, but the Windows and macOS libraries in libsignal-client won't automatically be excluded from your final app. You can explicitly exclude them using `packagingOptions`: ``` android { // ... packagingOptions { resources { excludes += setOf("libsignal_jni*.dylib", "signal_jni*.dll") } } // ... } ``` You can additionally exclude `libsignal_jni_testing.so` if you do not plan to use any of the APIs intended for client testing. ## Swift To learn about the Swift build process see [``swift/README.md``](swift/) ## Node You'll need Node installed to build. If you have [nvm][], you can run `nvm use` to select an appropriate version automatically. We use `npm` as our package manager, and `node-gyp` to control building the Rust library. ```shell $ cd node $ nvm use $ npm install $ npx node-gyp rebuild # clean->configure->build $ npm run tsc $ npm run test ``` When testing changes locally, you can use `npm run build` to do an incremental rebuild of the Rust library. Alternately, `npm run build-with-debug-level-logs` will rebuild without filtering out debug- and verbose-level logs. When exposing new APIs to Node, you will need to run `rust/bridge/node/bin/gen_ts_decl.py` in addition to rebuilding. [nvm]: https://github.com/nvm-sh/nvm ### NPM Signal publishes the NPM package `@signalapp/libsignal-client` for its own use, including native libraries for Windows, macOS, and Debian-flavored Linux. Both x64 and arm64 builds are included for all three platforms, but the arm64 builds for Windows and Linux are considered experimental, since there are no official builds of Signal for those architectures. # Contributions Signal does accept external contributions to this project. However unless the change is simple and easily understood, for example fixing a bug or portability issue, adding a new test, or improving performance, first open an issue to discuss your intended change as not all changes can be accepted. Contributions that will not be used directly by one of Signal's official client apps may still be considered, but only if they do not pose an undue maintenance burden or conflict with the goals of the project. Signing a [CLA (Contributor License Agreement)](https://signal.org/cla/) is required for all contributions. ## Code Formatting and Acknowledgments You can run the styler on the entire project by running: ```shell just format-all ``` You can run more extensive tests as well as linters and clippy by running: ```shell just check-pre-commit ``` When making a PR that adjusts dependencies, you'll need to regenerate our acknowledgments files. See [``acknowledgments/README.md``](acknowledgments/). # Legal things ## Cryptography Notice This distribution includes cryptographic software. The country in which you currently reside may have restrictions on the import, possession, use, and/or re-export to another country, of encryption software. BEFORE using any encryption software, please check your country's laws, regulations and policies concerning the import, possession, or use, and re-export of encryption software, to see if this is permitted. See <http://www.wassenaar.org/> for more information. The U.S. Government Department of Commerce, Bureau of Industry and Security (BIS), has classified this software as Export Commodity Control Number (ECCN) 5D002.C.1, which includes information security software using or performing cryptographic functions with asymmetric algorithms. The form and manner of this distribution makes it eligible for export under the License Exception ENC Technology Software Unrestricted (TSU) exception (see the BIS Export Administration Regulations, Section 740.13) for both object code and source code. ## License Copyright 2020-2024 Signal Messenger, LLC Licensed under the GNU AGPLv3: https://www.gnu.org/licenses/agpl-3.0.html ", Assign "at most 3 tags" to the expected json: {"id":"407","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"