libsparkcrypto - A cryptographic library implemented in SPARK 2014.

libsparkcrypto is a formally verified implementation of several widely used cryptographic algorithms using the SPARK 2014 programming language and toolset [1]. For the complete library proofs of the absence of run-time errors like type range violations, division by zero and numerical overflows are available. Some of its subprograms include proofs of partial correctness.

The distribution contains test cases for all implemented algorithms and a benchmark to compare its performance with the OpenSSL library [2].

Copyright, Warranty and Licensing

Copyright (C) 2011-2017 Stefan Berghofer Copyright (C) 2010-2011,2018 Alexander Senier Copyright (C) 2010-2017 secunet Security Networks AG

All rights reserved.

libsparkcrypto is released under the simplified BSD license:

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Features

This version of libsparkcrypto implements the following cryptographic algorithms and modes:

AES-128, AES-192, AES-256

AES-CBC (all supported AES modes)

SHA-1

HMAC-SHA1

SHA-256, SHA-384, SHA-512

HMAC-SHA-256, HMAC-SHA-384, HMAC-SHA-512

PRF-HMAC-SHA-256, PRF-HMAC-SHA-384, PRF-HMAC-SHA-512

RIPEMD-160

HMAC-RIPEMD-160

ECDSA, ECGDSA

Development version

The current development version of libsparkcrypto is available through its GIT [3] repository: https://github.com/Componolit/libsparkcrypto.git

A browsable version of the repository is also available here: https://github.com/Componolit/libsparkcrypto

Building and installing

Required tools

To build and prove libsparkcrypto, the following tools are required:

GNAT (recent Pro or FSF)

SPARK 2014 (tested with Pro 19.0 and Community 2018)

GNU make

OpenSSL (for building the benchmark, tested with 1.1.1j)

The primary development environments of libsparkcrypto are Debian (x86_64) and Ubuntu (x86_64). Though the source and project files should be system independent, the Makefiles assume a UNIXish system (cygwin seems to work). Tools like mkdir , uname , tail and install must be present in the systems search path.

Build process

To build libsparkcrypto, change to the source directory and type:

$ make

You can install the library to <destination>, by typing:

$ make DESTDIR=<destination> install

Supported systems

libsparkcrypto was successfully built and tested on the following systems:

operating system architecture toolchain Debian 9 x86_64 SPARK Pro 19.0, GNAT Pro 19.0 Debian 9 x86_64 GNAT Community 2018

Please send bug reports and comments to Alexander Senier <senier@componolit.com>.

Using libsparkcrypto

Examples for using libsparkcrypto can be found in the tests subdirectory.

A user of the library has to provide a shadow for the package Interfaces providing a type definition for at least Unsigned_8 , Unsigned_32 and Unsigned_64 .

Extending libsparkcrypto

You are welcome to extend libsparkcrypto according to the terms of the simplified BSD license referenced above. Please obey the following rules when contributing changes back to the project:

Make sure no undischarged VCs remain.

Make sure the code compiles in both modes MODE=release and MODE=debug.

Provide reference to documents and test cases for the parts you implemented.

Make sure you successfully ran the test suite ( make test ).

). Try to stay consistent with the current style of the source.

If feasible, implement a benchmark for your code.

Create a pull request on GitHub

The Directory structure of libsparkcrypto is as follows:

directory content src/shared sources analyzed by SPARK and used by Ada compiler src/spark sources only analyzed by SPARK src/ada sources only used by Ada compiler

The directories src/ada and src/shared have a sub-directory generic , which contains platform independent code. Furthermore, there are feature-specific directories like little_endian and architecture-specific directories like x86_64 which are included to proof and build steps as configured.

Configuration is performed automatically by the top-level Makefile and can be altered by passing the following variables to make :

variable description ARCH CPU architecture as reported by uname -m . MODE Build mode ( release or debug ). OPT Optimization level to use ( s , 0 , 1 , 2 or 3 ). SHARED Build a shared library ( 0 , 1 ). RUNTIME Runtime to build for ( native or zfp ). NO_TESTS Disable tests step. NO_SPARK Disable SPARK proof step. NO_ISABELLE Disable ISABELLE proof step. TARGET_CFG Target system configuration. SPARK_DIR Base directory of the SPARK installation. DESTDIR Installation base directory.

Credits

Thanks to Adrian-Ken Rüegsegger and Reto Buerki for hosting the project's GIT repository.

Thanks to Adacore and Altran Praxis for review, comments and support with many tricky problems.

[2] OpenSSL: The Open Source toolkit for SSL/TLS - http://www.openssl.org