Libcose is a C library aiming to implement the full COSE standard. Libcose is aimed at constrained devices without dynamic memory allocation, libcose will never call malloc related calls by itself. However it does require a simple block array allocator for cbor management.

Libcose implements modern ed25519 based signatures for signing. ECDSA based signing and verification might be implemented at some point. RSA will probably be skipped.

Dependencies:

cn-cbor
Either TweetNaCl or libsodium as crypto library
A memory block allocator (can be malloc/calloc based)

Building

To build a shared library from libcose:

make lib

Default libcose will try to link against libsodium for the crypto. Note that libcose also requires cn-cbor compiled with context pointer support. When building cn-cbor, please use cmake -Duse_context=ON to enable the context pointer.

Testing

libcose is supplied with a test suite covering most cases. Testing requires CUnit as test framework. Running al tests is done with

make test

Contributing

Open an issue, PR, the usual. Builds must pass before merging. Currently Travis tests the full test suite. In addition Travis also runs clang-tidy to check for simple style and code mistakes.

Limitations

Due to time constraints, for now only signing is implemented. Contributions for encryption and authentication is of course welcome.

As libcose is aimed at constrained devices a number of configurables are compile time defined. This includes the number of headers and the number signatures that are allowed in a single signature structure.