hardening

.github/workflows/rust.yml

@@ -2,23 +2,62 @@ name: Rust
 
 on:
   push:
-    branches: [ "main" ]
+    branches: ["main"]
   pull_request:
-    branches: [ "main" ]
+    branches: ["main"]
 
 env:
   CARGO_TERM_COLOR: always
 
 jobs:
   build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust Toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt, clippy
+
+      - name: Check Code Format
+        run: cargo fmt --all -- --check
 
+      - name: Code Lint
+        run: cargo clippy --all-targets --all-features -- -D warnings
+
+      - name: Build
+        run: cargo build --verbose --all-features
+
+      - name: Run tests
+        run: cargo test --verbose --all-features
+
+  msrv:
+    name: Verify MSRV (1.85)
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
-    - name: Build
-      run: cargo build --verbose
-    - name: Run tests
-      run: |
-        cargo test --verbose
-        cargo test --verbose --all-targets --all-features
+      - uses: actions/checkout@v4
+
+      - name: Install Rust Toolchain (1.85)
+        uses: dtolnay/rust-toolchain@1.85.0
+
+      - name: Check
+        run: cargo check --all-features
+
+  audit:
+    name: Security Audit
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust Toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install cargo-audit
+        run: cargo install cargo-audit
+
+      - name: Run cargo audit
+        run: cargo audit

CHANGELOG.md

@@ -5,6 +5,157 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.8] - 2026-07-16
+
+### Security
+- Removed `rsa` crate from dependency tree by dropping the unnecessary `crypto`
+  feature from `ssh-key` on native targets (was `["crypto"]`, now
+  `["alloc", "ecdsa", "ed25519"]` — matching the wasm target). multi-sig only
+  uses `ssh_key::Signature`/`Algorithm`/`AlgorithmName` (encoding types); the
+  `crypto` feature pulled in `ssh-key`'s `rsa` feature, which dragged in the
+  vulnerable `rsa 0.10.0-rc.18` (RUSTSEC-2023-0071, Marvin Attack). The RSA
+  view uses `Algorithm::Other(...)` not `Algorithm::Rsa`, so no `rsa` feature
+  is needed.
+- Removed unmaintained `serde_cbor` dev-dependency (RUSTSEC-2021-0127). Replaced
+  with `ciborium` (already a runtime dependency) in 4 CBOR round-trip tests.
+
+### Changed
+- `Multisig` non-human-readable `Deserialize` path now uses
+  `deserialize_byte_buf` with a `ByteBufVisitor` that accepts borrowed bytes,
+  owned bytes, and byte buffers — compatible with `serde_test`, `serde_cbor`,
+  and `ciborium` (the previous `&'de [u8]` bound only worked with
+  deserializers that lend borrowed slices).
+
+### Dependencies
+- `ssh-key` (native target): `features = ["crypto"]` →
+  `default-features = false, features = ["alloc", "ecdsa", "ed25519"]`
+- Removed `serde_cbor = "0.11"` dev-dependency
+- Dependency count reduced from 233 to 221 crates
+
+## [1.0.7] - 2026-07-16
+
+### Security
+- Added `MAX_DECODED_SIZE = 16 MiB` total decoded-size cap to
+  `Multisig::try_decode_from` (tracks consumed bytes across the attribute
+  decode loop, returns `Error::InputTooLarge`). Per-attribute payloads are
+  also individually capped by `Varbytes::MAX_DECODED_SIZE` via `multi_util`.
+  Mitigates CWE-400.
+- Added `MAX_THRESHOLD_PARTICIPANTS = 1024` cap in `threshold_meta.rs`,
+  enforced in `bls12381.rs` `SigShare::try_decode_from` where threshold/limit
+  values are decoded (returns `Error::TooManyParticipants`). Mitigates CWE-400.
+- Added `new_from_bls_signature_with_codec(codec, sig)` and
+  `new_from_bls_signature_share_with_codec(codec, threshold, limit, sigshare)`
+  constructors that take an explicit BLS12-381 codec, avoiding the
+  length-based codec inference heuristic (48 bytes → G1, 96 bytes → G2).
+- Deprecated `new_from_bls_signature` and `new_from_bls_signature_share` with
+  `#[deprecated]` notes pointing to the explicit-codec constructors.
+- Updated internal `combine` method to use `new_from_bls_signature_with_codec`.
+
+### Changed
+- Upgraded to Edition 2024 (`edition = "2024"`, `rust-version = "1.85"`).
+- Added `[lints.clippy]` (pedantic/nursery/cargo at warn) and
+  `[lints.rust] unsafe_code = "deny"` with targeted `#![allow(...)]` for
+  stylistic lints.
+- Added `Error::InputTooLarge { claimed, max }` and
+  `Error::TooManyParticipants(usize, usize)` error variants.
+- Exported `MAX_DECODED_SIZE` and `MAX_THRESHOLD_PARTICIPANTS` from crate root.
+
+### CI
+- Expanded CI from build+test to include: fmt check, clippy `-D warnings`,
+  MSRV (1.85) check, and cargo audit job.
+
+### Documentation
+- Added `SECURITY.md` documenting std-only status, RC dependencies
+  (`blsful`, `ssh-key`, `vsss-rs`), decoded-size caps, BLS codec inference,
+  and memory safety properties.
+
+### Tests
+- Added `test_too_many_attributes_rejected` and `test_valid_roundtrip_with_caps`.
+
+## [1.0.6] - 2026-07-16
+
+### Changed
+- Made `serde` a required dependency (the `threshold_meta` module always
+  derives `Serialize`/`Deserialize` for its CBOR blob types). The `serde`
+  feature flag is retained for backward compatibility and controls only the
+  public `serde` impl module.
+- Upgraded `chacha20poly1305` from 0.10 to 0.11.
+- Upgraded `getrandom` from 0.2 to 0.4.
+- Simplified `Error` type (removed redundant variants).
+
+## [1.0.5] - 2026-07-14
+
+### Added
+- Synced from bettersign workspace: PQC signature views (ML-DSA, FN-DSA,
+  MAYO, SLH-DSA, RSA, NIST-P), hybrid signature views (Ed25519+MAYO2,
+  Ed25519+ML-DSA-65, Ed25519+FN-DSA-512), `types.rs` module with type-safe
+  wrappers.
+- Added threshold disclosure modes (`ThresholdDisclosure::Full`,
+  `Partial`, `FullConfidentialial`) with ChaCha20-Poly1305 AEAD encryption
+  of threshold metadata (`threshold_meta.rs`).
+- Added `AttrId` variants: `ThresholdDisclosure`,
+  `EncryptedThresholdMeta`, `ThresholdMetaCipher`.
+- Added `DisclosureView` for threshold disclosure mode operations.
+- Added comprehensive test suite: `edge_case_tests.rs`,
+  `proptest_tests.rs`, `security_tests.rs`.
+- Added `Builder::with_disclosure` and
+  `Builder::with_encrypted_threshold_meta`.
+- Added `MAX_ATTRIBUTES = 256` cap on attribute count in
+  `Multisig::try_decode_from` (returns `Error::TooManyAttributes`).
+- Added benchmarks (`multisig_bench.rs`).
+- Added BLS threshold signing support with share combine/split.
+- Added SSH signature conversion (`ConvView::to_ssh_signature`).
+- Added `PayloadEncoding` attribute and `AttrView` trait.
+- Added `Null` impl for `Multisig`.
+
+### Changed
+- Refactored `Multisig` to be attributes-based (like `Multikey`).
+- Updated `README.md` with comprehensive documentation.
+- Updated codec names for multicodec table sync.
+- Updated `blsful` dependency.
+- `ssh-key` `default-features = false` for `wasm32-*` targets.
+- Put `ssh-*` behind a feature flag for non-wasm32 targets.
+
+### Fixed
+- Fixed wire serialization.
+- Fixed codec updates.
+- Fixed serde of `AttrId`.
+- Fixed builder from BLS signature.
+- Fixed clippy warnings.
+
+## [1.0.4] - 2025-07-18
+
+### Changed
+- Simplified `Deserialize` implementation for `Multisig`.
+- Fixed clippy warnings.
+
+## [1.0.3] - 2024-12-02
+
+### Changed
+- Updated `blsful` crate version.
+
+## [1.0.2] - 2024-08-27
+
+### Added
+- WASM support: `ssh-key` with `default-features = false` for `wasm32-*`
+  targets.
+- CI testing for all targets and features.
+
+### Changed
+- Updated codec names for multicodec table sync.
+- Updated `LICENSE` file.
+- Fixed multibase dependency.
+- Fixed codec updates.
+- Fixed clippy warnings.
+
+### Fixed
+- Fixed tests for updated dependencies.
+
+## [1.0.1] - 2026-07-13
+
+### Fixed
+- Fixed codec names after multicodec table sync.
+
 ## [1.0.0] - 2026-07-13
 
 ### Changed

Cargo.toml

@@ -1,7 +1,8 @@
 [package]
 name = "multi-sig"
-version = "1.0.6"
-edition = "2021"
+version = "1.0.8"
+edition = "2024"
+rust-version = "1.85"
 authors = ["Dave Grantham <dwg@linuxprogrammer.org>"]
 description = "Multisig self-describing multicodec implementation for digital signatures"
 repository = "https://github.com/cryptidtech/multi-sig.git"
@@ -40,17 +41,24 @@ ssh-key = { version = "0.7.0-rc.11", default-features = false, features = ["allo
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 blsful = { version = "4.0.0-rc1", default-features = false, features = ["blst"] }
-ssh-key = { version = "0.7.0-rc.11", features = ["crypto"] }
+ssh-key = { version = "0.7.0-rc.11", default-features = false, features = ["alloc", "ecdsa", "ed25519"] }
 
 [dev-dependencies]
 criterion = { version = "0.8", features = ["html_reports"] }
 hex = "0.4"
 proptest = "1.4"
-serde_cbor = "0.11"
 serde_json = "1.0"
 serde_test = "1.0"
 
 [[bench]]
 name = "multisig_bench"
 harness = false
 path = "benches/multisig_bench.rs"
+
+[lints.clippy]
+pedantic = { level = "warn", priority = -1 }
+nursery = { level = "warn", priority = -1 }
+cargo = { level = "warn", priority = -1 }
+
+[lints.rust]
+unsafe_code = "deny"

SECURITY.md

@@ -0,0 +1,66 @@
+# Security Policy
+
+## Overview
+
+The `multi-sig` crate provides self-describing digital signatures following
+the multisig specification. This document outlines the security properties,
+threat model, and guarantees of this crate.
+
+## std-only Status
+
+This crate is **std-only**. It depends on `std::collections::BTreeMap`,
+`std::fmt`, and `unsigned-varint` with the `std` feature. The crypto
+dependency stack (`blsful`, `ssh-key`, `chacha20poly1305`) also requires
+std. A `no_std` conversion is not planned for this crate.
+
+## Release-Candidate Dependencies
+
+This crate depends on the following release-candidate (RC) crates:
+
+- `blsful = "4.0.0-rc1"` — BLS12-381 signature implementation
+- `ssh-key = "0.7.0-rc.11"` — SSH key/signature encoding
+- `vsss-rs = "6.0.0-rc2"` (transitive via `blsful`) — verifiable secret
+  sharing
+
+These are pinned to RC versions because stable releases are not yet
+available. This is a **tracked acceptance**: the RC versions are reviewed
+on each release and will be upgraded to stable when available. Consumers
+should be aware that RC APIs may change before stabilisation.
+
+## Decoded-Size Caps
+
+The decoder enforces the following caps on untrusted wire data to mitigate
+CWE-400 (Uncontrolled Resource Consumption):
+
+- **`MAX_ATTRIBUTES = 256`** — maximum number of attributes per `Multisig`.
+- **`MAX_DECODED_SIZE = 16 MiB`** — maximum total decoded bytes per
+  `Multisig`. Tracked across the attribute decode loop.
+- **`MAX_THRESHOLD_PARTICIPANTS = 1024`** — maximum threshold or limit
+  value in a BLS signature share.
+- Per-attribute `Varbytes` payloads are individually capped by
+  `multi_util::varbytes::MAX_DECODED_SIZE` (16 MiB).
+
+Exceeding any cap returns a clean `Err` (`Error::TooManyAttributes`,
+`Error::InputTooLarge`, or `Error::TooManyParticipants`); the decoder never
+panics on oversized input.
+
+## BLS12-381 Codec Inference
+
+The deprecated `Builder::new_from_bls_signature` and
+`Builder::new_from_bls_signature_share` constructors infer the BLS12-381
+codec (G1 vs G2) from the compressed-point byte length (48 bytes -> G1,
+96 bytes -> G2). This is a heuristic, not cryptographic binding. Prefer
+`new_from_bls_signature_with_codec` and
+`new_from_bls_signature_share_with_codec`, which take an explicit codec
+parameter.
+
+## Memory Safety
+
+- **No unsafe code**: `#![deny(unsafe_code)]` is enforced at compile time.
+- **Input validation**: All decode paths validate lengths, attribute
+  counts, and codec identifiers.
+
+## Reporting Vulnerabilities
+
+Report security issues via the project's GitHub issue tracker or privately
+to the maintainers.

benches/multisig_bench.rs

@@ -1,7 +1,12 @@
 // SPDX-License-Identifier: Apache-2.0
 //! Performance benchmarks for multi-sig
+#![allow(
+    clippy::semicolon_if_nothing_returned,
+    clippy::uninlined_format_args,
+    clippy::doc_markdown
+)]
 
-use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
+use criterion::{BenchmarkId, Criterion, criterion_group, criterion_main};
 use multi_codec::Codec;
 use multi_sig::{Builder, Multisig, SIG_CODECS};
 use multi_trait::TryDecodeFrom;

src/attrid.rs

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: Apache-2.0
-use crate::{error::AttributesError, Error};
+use crate::{Error, error::AttributesError};
 use multi_trait::{EncodeInto, TryDecodeFrom};
 use std::fmt;
 

src/error.rs

@@ -44,12 +44,31 @@ pub enum Error {
     DuplicateAttribute(u8),
     /// Attribute count exceeds the configured maximum
     ///
-    /// Returned by [`crate::ms::Multisig::try_decode_from`] when the number of
+    /// Returned by `Multisig::try_decode_from` when the number of
     /// attributes declared in the wire data exceeds
     /// [`crate::ms::MAX_ATTRIBUTES`]. Bounds the work a crafted input can
     /// force the decoder to perform and mitigates CWE-400.
     #[error("attribute count {0} exceeds maximum {1}")]
     TooManyAttributes(usize, usize),
+    /// Decoded size exceeds the configured maximum
+    ///
+    /// Returned by `Multisig::try_decode_from` when the total
+    /// decoded byte count exceeds [`crate::ms::MAX_DECODED_SIZE`]. Bounds the
+    /// worst-case allocation for untrusted wire data and mitigates CWE-400
+    /// (Uncontrolled Resource Consumption).
+    #[error("decoded size {claimed} exceeds maximum {max}")]
+    InputTooLarge {
+        /// The number of bytes claimed by the wire data
+        claimed: usize,
+        /// The configured maximum decoded size
+        max: usize,
+    },
+    /// Participant count exceeds the configured maximum
+    ///
+    /// Returned when a threshold or limit value decoded from a BLS share
+    /// exceeds [`crate::views::threshold_meta::MAX_THRESHOLD_PARTICIPANTS`].
+    #[error("participant count {0} exceeds maximum {1}")]
+    TooManyParticipants(usize, usize),
     /// Failed Varsig conversion
     #[error("Failed Varsig conversion: {0}")]
     FailedConversion(String),
@@ -189,6 +208,8 @@ impl Error {
             Self::MissingSigil => "MissingSigil",
             Self::DuplicateAttribute(_) => "DuplicateAttribute",
             Self::TooManyAttributes(_, _) => "TooManyAttributes",
+            Self::InputTooLarge { .. } => "InputTooLarge",
+            Self::TooManyParticipants(_, _) => "TooManyParticipants",
             Self::FailedConversion(_) => "FailedConversion",
             Self::UnsupportedAlgorithm(_) => "UnsupportedAlgorithm",
         }