isabella232 / nim-bearssl

BearSSL wrapper in Nim

bearssl

Simple BearSSL wrapper for Nim, fully integrated with the Nim build system.

Applications using nim-bearssl are fully stand-alone, needing no additional DLL or shared library.

Usage

The library is organised into two parts:

• bearssl/ (except for abi) exposes thin wrappers around the raw ABI making the functions more convenient to use in Nim
• bearssl/abi exposes the raw C functions of bearssl

For each bearssl header file, a corresponding Nim file exists - bearssl_rand.h ~ bearssl/rand.nim.

# You can import the whole library
import bearssl

# ... or simply parts thereof, which can save compilation time
import bearssl/rand

In general, the mappings follow the conventions of the original BearSSL library closely. The following conventions exist:

• the br_ prefix has been dropped throughout
• functions taking a XxxContext* use var and not ptr
• byte replaces unsigned char* - this type is predominantly used for byte buffers
• uint used instead of csize_t - these are the same type in Nim, but spelled more conveniently
  • Canonical nim code will have to be careful when converting existing int lengths, looking out for out-of-range values

In addition to the raw C-like api, convenience functions are added where applicable - these follow a similar set of conventions:

• named after the function they simplify, but take advantage of types and overload support in Nim
• help turn pointers and bytes into Nim types

Installation

You can install the developement version of the library through nimble with the following command:

nimble install bearssl

BearSSL itself is compiled as part of your project - there is no need to install any third-party libraries.

Developer notes

When updating the library, c2nim is used via regenerate.sh to update the RAW ABI files. Manual editing is then needed to make a few adjustments to the mapping, after which the files can be generated.

When adding new convenience functions, these should be added to bearssl/ instead of the generated files.

License

Licensed and distributed under either of

• MIT license: LICENSE-MIT or http://opensource.org/licenses/MIT

or

• Apache License, Version 2.0, (LICENSE-APACHEv2 or http://www.apache.org/licenses/LICENSE-2.0)

at your option. This file may not be copied, modified, or distributed except according to those terms.