Add COSE structure extensions that allow use of predefined cryptographic backends + an OpenSSL based backend.

.github/workflows/check.yml

@@ -11,7 +11,7 @@ jobs:
     name: Check
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -22,25 +22,27 @@ jobs:
           command: check
 
   check_nostd:
-   name: Check (no_std)
-   runs-on: ubuntu-latest
-   steps:
-     - uses: actions/checkout@v2
-     - uses: actions-rs/toolchain@v1
-       with:
-         profile: minimal
-         toolchain: stable
-         override: true
-     - uses: actions-rs/cargo@v1
-       with:
-         command: check
-         args: --no-default-features
+    name: Check (no_std)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - uses: actions-rs/cargo@v1
+        with:
+          command: check
+          args: --no-default-features
 
   test:
     name: Test Suite
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -51,25 +53,25 @@ jobs:
           command: test
 
   test_nostd:
-   name: Test Suite (no_std)
-   runs-on: ubuntu-latest
-   steps:
-     - uses: actions/checkout@v2
-     - uses: actions-rs/toolchain@v1
-       with:
-         profile: minimal
-         toolchain: stable
-         override: true
-     - uses: actions-rs/cargo@v1
-       with:
-         command: test
-         args: --no-default-features
+    name: Test Suite (no_std)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --no-default-features --features openssl
 
   fmt:
     name: Rustfmt
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -84,7 +86,7 @@ jobs:
   clippy_check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: rustup component add clippy
       - uses: actions-rs/clippy-check@v1
         with:
@@ -94,7 +96,9 @@ jobs:
   test_coverage:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: nightly
@@ -116,4 +120,4 @@ jobs:
         uses: coverallsapp/github-action@master
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
-          path-to-lcov: ${{ steps.coverage.outputs.report }}
+          path-to-lcov: ${{ steps.coverage.outputs.report }}

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "tests/cose_examples"]
+	path = tests/cose_examples
+	url = https://github.com/cose-wg/Examples.git

CHANGELOG.md

@@ -5,23 +5,73 @@ 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).
 
+## [Unreleased]
+
+This release reworks the access token API and fully implements extensions to the COSE structures provided by `coset`
+that allow using pre-defined cryptographic backends.
+This way, it is no longer required for applications to implement cryptographic operations and logic to verify that
+COSE structures match the specification.
+
+> [!NOTE]
+> The long-term plan is to integrate these extensions into `coset` at some point (assuming that they would be
+> interested in this code). This might come with minor API adjustments (e.g. by removing some parameters to builder
+> methods that already have their own builder method, but whose fields we can't access from outside of `coset`), but the
+> basic design of this module should now be quite stable.
+> Applications can expect to only have to make minor changes in calls to these operations for the foreseeable future.
+
+### Added
+
+- An entire new submodule `token/cose` that is responsible for easier handling of creation and verification of COSE
+  structures.
+  Instead of manually defining glue code to cryptographic libraries for each call and checking whether the COSE
+  structure is specification-compliant, this module takes care of most of the validation and leaves the basic
+  cryptographic operations to reusable predefined cryptographic backends.
+    - `CoseEncryptExt`/`CoseEncrypt0Ext`/`CoseSignExt`/`CoseSign1Ext`/`CoseMacExt`/`CoseMac0Ext`: Extension traits for
+      the corresponding `coset` types that allow for easy verification of those COSE structures.
+    - `CoseEncryptBuilderExt`/`CoseEncrypt0BuilderExt`/`CoseSignBuilderExt`/`CoseSign1BuilderExt`/`CoseMacBuilderExt`/
+      `CoseMac0BuilderExt`: Extension traits for the corresponding `coset` types that allow for easy creation of those
+      COSE structures.
+    - `CoseRecipientExt`/`CoseRecipientBuilderExt`: Extensions for creating and decrypting COSE recipients, which may
+      be used in `CoseEncrypt` and `CoseMac` structures to encode data for multiple recipients at once.
+- A cryptographic backend based on the `openssl` crate (a `RustCrypto` backend will be following soon, see #20).
+
+### Changed
+
+- `encrypt_access_token_multiple`/`decrypt_access_token_multiple`: Parameters have been adjusted to use the new COSE
+  extensions
+- `sign_access_token_multiple` / `verify_access_token_multiple`: Parameters have been adjusted to use the new COSE
+  extensions
+- `encrypt_access_token`/`decrypt_access_token`: Parameters have been adjusted to use the new COSE extensions
+- `sign_access_token` / `verify_access_token`: Parameters have been adjusted to use the new COSE extensions
+- `CoseCipher`/`CoseEncryptCipher`/`CoseSignCipher`/`CoseMacCipher`: Renamed to `CryptoBackend`/`EncryptCryptoBackend`/
+  `SignCryptoBackend`/`MacCryptoBackend` and fully reworked. These traits now only need to implement the basic
+  cryptographic operations, almost everything else (validation of header parameters, identifying suitable keys, ...) is
+  now handled by the `coset` extensions.
+
+### Removed
+
+- `MultipleEncryptCipher`/`MultipleSignCipher`: No longer required as the cryptographic backends no longer have to
+  handle those differently. This is taken care of by the `token/cose` module now.
+
 ## [0.4.0] --- 2023-03-27
 
 This release mainly adds support for multiple token recipients, deals with the newly released RFCs,
-and fixes `no_std` support. 
+and fixes `no_std` support.
 Note that the cipher interfaces have been refactored in a major way.
 
 ### Added
 
 - The `CoapOscore` profile has been added as an `AceProfile`.
 - Support for multiple token recipients has been added. Specifically, the following new methods have been added:
-  - `encrypt_access_token_multiple` / `decrypt_access_token_multiple`: Creates a new access token encoded as a
-    `CoseEncrypt` rather than a `CoseEncrypt0`. The user passes in a vector of keys on encryption, these will then be
-    used as Key Encryption Keys. The Content Encryption Key is generated by the `MultipleEncryptCipher` required by
-    the function. On decryption, the correct recipient structure will be identified by the key ID of the passed-in key.
-  - `sign_access_token_multiple` / `decrypt_access_token_multiple`: Creates a new access token encoded as a `CoseSign`
-    rather than a `CoseSign1`. The user passes in a vector of keys when signing, and a recipient will be created
-    for each key. When verifying, the correct recipient structure will be identified by the key ID of the passed-in key.
+    - `encrypt_access_token_multiple` / `decrypt_access_token_multiple`: Creates a new access token encoded as a
+      `CoseEncrypt` rather than a `CoseEncrypt0`. The user passes in a vector of keys on encryption, these will then be
+      used as Key Encryption Keys. The Content Encryption Key is generated by the `MultipleEncryptCipher` required by
+      the function. On decryption, the correct recipient structure will be identified by the key ID of the passed-in
+      key.
+    - `sign_access_token_multiple` / `decrypt_access_token_multiple`: Creates a new access token encoded as a `CoseSign`
+      rather than a `CoseSign1`. The user passes in a vector of keys when signing, and a recipient will be created
+      for each key. When verifying, the correct recipient structure will be identified by the key ID of the passed-in
+      key.
 
 ### Changed
 
@@ -64,11 +114,11 @@ with `AifRestMethod` (using [`enumflags2`]).
   `AifRestMethodSet` has been added too.
   The reason for this is that this makes it possible to declare
   *single* REST methods in a type-safe manner.
-  - Note that any existing usages of `AifRestMethodSet` now need to
-    be replaced with the new corresponding API calls.
-  - Variant names are now using `PascalCase` instead of `UPPER_CASE`.
-  - Use the type `AifRestMethod` for a single REST method and
-    `AifRestMethodSet` for a set of REST methods.
+    - Note that any existing usages of `AifRestMethodSet` now need to
+      be replaced with the new corresponding API calls.
+    - Variant names are now using `PascalCase` instead of `UPPER_CASE`.
+    - Use the type `AifRestMethod` for a single REST method and
+      `AifRestMethodSet` for a set of REST methods.
 - The `derive_builder` dependency has been updated to 0.11.2.
 
 ### Fixed
@@ -84,13 +134,14 @@ This release focuses on introducing [AIF] and [libdcaf]-support.
 - Support for scopes using the
   [Authorization Information Format (AIF) for ACE](https://www.rfc-editor.org/rfc/rfc9237.html).
   For this purpose, the following types have been added:
-  - `AifEncodedScope`, representing an AIF-encoded scope (surprise)
-  - `AifEncodedScopeElement`, a single element in an AIF-encoded scope
-    - `AifRestMethodSet`, encoding a set of REST methods
-- Support for scopes used by the [libdcaf] implementation 
+    - `AifEncodedScope`, representing an AIF-encoded scope (surprise)
+    - `AifEncodedScopeElement`, a single element in an AIF-encoded scope
+        - `AifRestMethodSet`, encoding a set of REST methods
+- Support for scopes used by the [libdcaf] implementation
   (a variant of AIF-encoded scopes).
 
 ### Fixed
+
 - Binary-encoded scopes are now properly serialized.
 - Some incorrect documentation regarding scopes has been corrected.
 
@@ -101,6 +152,7 @@ For more extensive documentation, consult the
 [crate-level documentation](https://docs.rs/dcaf).
 
 ### Added
+
 - CBOR de-/serializable model of the ACE-OAuth framework has been added:
     - Binary- and text-encoded scopes
     - Access token requests and responses

Cargo.toml

@@ -4,31 +4,37 @@ description = "An implementation of the ACE-OAuth framework"
 version = "0.4.0"
 edition = "2021"
 authors = ["Falko Galperin <[email protected]>"]
-rust-version = "1.58"
+rust-version = "1.62"
 license = "MIT OR Apache-2.0"
 keywords = ["no_std", "framework", "oauth", "ace"]
 categories = ["authentication", "data-structures", "embedded", "encoding", "no-std"]
 repository = "https://github.com/namib-project/dcaf-rs"
 exclude = [
-    ".gitlab/*", ".gitlab-ci.yml"
+    ".gitlab/*", ".gitlab-ci.yml", ".github/*"
 ]
 
 [features]
-default = ["std"]
+default = ["std", "openssl"]
 std = ["serde/std", "ciborium/std", "serde_bytes/std", "erased-serde/std", "derive_builder/std"]
 
 [dependencies]
 serde = { version = "1.0", default-features = false, features = ["derive"] }
 ciborium = { version = "^0.2", default-features = false }
 ciborium-io = { version = "^0.2", default-features = false }
-coset = { version = "^0.3", default-features = false }
+coset = { version = "^0.3", default-features = false, git = "https://github.com/namib-project/coset.git", branch = "fix_zero_length_map" }#, path = "../coset" }
 serde_bytes = { version = "^0.11", default-features = false, features = ["alloc"] }
-erased-serde = { version = "^0.3", default-features = false, features = ["alloc"] }
-derive_builder = { version = "^0.12", default-features = false }
-strum = { version = "^0.24", default-features = false, features = ["derive"] }
-strum_macros = { version = "^0.24", default-features = false }
+erased-serde = { version = "0.4.5", default-features = false, features = ["alloc"] }
+derive_builder = { version = "0.20", default-features = false, features = ["alloc"] }
+strum = { version = "0.26", default-features = false, features = ["derive"] }
+strum_macros = { version = "0.26", default-features = false }
 enumflags2 = { version = "^0.7", default-features = false }
 rand = { version = "^0.8", default-features = false }
+openssl = { version = "^0.10", optional = true }
+lazy_static = "1.4.0"
 
 [dev-dependencies]
-hex = { version = "^0.4" }
+hex = { version = "^0.4", features = ["serde"] }
+base64 = "0.22.1"
+rstest = "0.21.0"
+serde_json = "1.0.118"
+rand = { version = "^0.8", default-features = false, features = ["std_rng", "std"] }