wolfCOSE

wolfCOSE is a lightweight C library implementing CBOR (RFC 8949) and COSE (RFC 9052/9053) using wolfSSL as the crypto backend.

Main Features

• Complete RFC 9052 message set: all six COSE message types, including multi-signer COSE_Sign and multi-recipient COSE_Encrypt / COSE_Mac
• Post-quantum signing: ML-DSA (Dilithium) at all three security levels
• 40 algorithms across signing, encryption, MAC, and key distribution
• Zero dynamic allocation: all operations use caller-provided buffers
• Tiny footprint: 7.5 KB .text minimal build (Sign1+ECC), 25.6 KB full (40 algorithms), zero .data/.bss
• Full COSE lifecycle in ~<1KB RAM (excluding wolfCrypt internals)
• Path to FIPS 140-3 via wolfCrypt FIPS Certificate #4718 (sole crypto dependency)

Supported Algorithms

Signing: ES256, ES384, ES512, EdDSA (Ed25519/Ed448), PS256/384/512, ML-DSA-44/65/87

Encryption: AES-GCM (128/192/256), ChaCha20-Poly1305, AES-CCM variants

MAC: HMAC-SHA256/384/512, AES-MAC

Key Distribution: Direct, AES Key Wrap, ECDH-ES+HKDF

COSE Message Types (RFC 9052)

wolfCOSE has implemented all RFC 9052 messages both single-actor and multi-actor variants:

Message	RFC 9052	API	Purpose
COSE_Sign1	Sec. 4.2	wc_CoseSign1_Sign / wc_CoseSign1_Verify	Single-signer signature
COSE_Sign	Sec. 4.1	wc_CoseSign_Sign / wc_CoseSign_Verify	Multi-signer (independent signatures over the same payload)
COSE_Encrypt0	Sec. 5.2	wc_CoseEncrypt0_Encrypt / wc_CoseEncrypt0_Decrypt	Single-recipient AEAD
COSE_Encrypt	Sec. 5.1	wc_CoseEncrypt_Encrypt / wc_CoseEncrypt_Decrypt	Multi-recipient (one ciphertext, many recipients via Direct / AES-KW / ECDH-ES)
COSE_Mac0	Sec. 6.2	wc_CoseMac0_Create / wc_CoseMac0_Verify	Single-recipient MAC
COSE_Mac	Sec. 6.1	wc_CoseMac_Create / wc_CoseMac_Verify	Multi-recipient MAC (shared MAC key, distributed to recipients)
COSE_Key / COSE_KeySet	Sec. 7	wc_CoseKey_Encode / wc_CoseKey_Decode	Key serialization for all key types

Prerequisites (wolfSSL)

wolfCOSE requires wolfSSL as its crypto backend. Minimum recommended version: v5.7.4 (first release with FIPS 204 final ML-DSA + the context-aware wc_dilithium_*_ctx_msg APIs). Older 5.x releases can technically be supported but require source-level changes; contact wolfSSL for commercial support.

Choose a build configuration based on the algorithms you need.

Minimal Build (ECC + AES-GCM)

This gives you COSE Sign1 (ES256/384/512) and Encrypt0 (AES-GCM):

cd wolfssl
./autogen.sh
./configure --enable-ecc --enable-aesgcm \
            --enable-sha384 --enable-sha512 --enable-keygen
make && sudo make install
sudo ldconfig

Algorithms enabled: ES256, ES384, ES512, AES-GCM-128/192/256

Minimal Build (Post-Quantum / ML-DSA only)

For pure post-quantum signing with ML-DSA-44/65/87:

cd wolfssl
./autogen.sh
./configure --enable-cryptonly --enable-dilithium
make && sudo make install
sudo ldconfig

Algorithms enabled: ML-DSA-44, ML-DSA-65, ML-DSA-87 (SHAKE-128/256 are pulled in automatically by --enable-dilithium.)

Full Build (All Algorithms)

cd wolfssl
./autogen.sh
./configure --enable-ecc --enable-ed25519 --enable-ed448 \
            --enable-curve25519 --enable-aesgcm --enable-aesccm \
            --enable-sha384 --enable-sha512 --enable-keygen \
            --enable-rsapss --enable-chacha --enable-poly1305 \
            --enable-dilithium --enable-hkdf --enable-aeskeywrap
make && sudo make install
sudo ldconfig

Build

# Core library (libwolfcose.a)
make

# Run unit tests
make test

# Build and run CLI tool round-trip tests (all algorithms)
make tool-test

# Run lifecycle demo (11 algorithms)
make demo

Build Targets

Target	Description
make all	Build libwolfcose.a (core library only)
make shared	Build libwolfcose.so
make test	Build + run CBOR and COSE unit tests
make tool	Build CLI tool (tools/wolfcose_tool)
make tool-test	Round-trip self-test for all 17 algorithms
make demo	Build + run lifecycle demo (11 algorithms)
make clean	Remove all build artifacts

Quick Start

Examples

See examples/ for complete working code:

• sign1_demo.c, encrypt0_demo.c, mac0_demo.c: algorithm demos
• lifecycle_demo.c: full edge-to-cloud workflow
• comprehensive/: algorithm matrix tests
• scenarios/: firmware signing, attestation, fleet config

CI / Testing

Runs on every push and PR:

• Build + Test: Ubuntu, macOS, GCC 10-14, Clang 14-18
• Comprehensive Tests: ~240 algorithm combination tests
• Static Analysis: cppcheck, Clang analyzer, GCC -fanalyzer
• MISRA C 2012: cppcheck --addon=misra checking all wolfCOSE code paths
• MISRA C 2023: strict GCC warnings and clang-tidy (bugprone-*, cert-*, clang-analyzer-*, misc-*)
• Coverity Scan: nightly defect analysis
• Advanced Internal Static Analysis: Fenrir wolfssl advanced static analysis tools
• Code Coverage: 99.3% for wolfcose.c, 100% for wolfcose_cbor.c

make coverage                  # Run tests with gcov
make coverage-force-failure    # Include crypto failure path testing

Documentation

Full documentation is available in the Wiki:

• Getting Started: Build instructions and first steps
• Message Types: All six RFC 9052 messages (Sign1, Sign, Encrypt0, Encrypt, Mac0, Mac) with code samples
• Algorithms: Complete list of 40 supported algorithms with COSE IDs
• API Reference: Function signatures, data structures, error codes
• Macros: Compile-time configuration options
• Testing: Test infrastructure, coverage, and failure injection
• Project Structure: Source file layout

Blogs

Blogs and update can be found here:

wolfCOSE Blogs

License

wolfCOSE is free software licensed under the GPLv3.

Copyright (C) 2026 wolfSSL Inc.

Support

Note: While wolfCOSE is currently maintained by wolfSSL developers, it is not yet classified as an officially supported product. It was designed from the ground up to meet the same quality standards as the rest of the wolfSSL suite with future adoption in mind. We are eager to transition this to a fully supported product as demand grows; if your organization requires official support or has specific feature requirements or you just have general questions or guidance with product, please reach out.

For commercial licensing, professional support contracts, or to discuss moving wolfCOSE into your production environment, contact wolfSSL.