This is a port of Peter Gutmann's cryptlib package to the Cryptech project's environment. This is a work in progress, and still at a very early stage as of this writing.

The main addition to the stock cryptlib environment is a set of Hardware Adaption Layer (HAL) implementations that use the Cryptech FPGA cores.

While we expect to be making more significant use of cryptlib in the future, the main purposes of this code at the moment are proof-of-concept and connecting the Cryptech cores to a more complete cryptographic programming environment for testing and development purposes.

Current status

At present, the Cryptech HAL code runs only on the Novena PVT1. There are three variants of the HAL, all using the I2C bus, but speaking different protocols:

  • An implementation using the coretest byte-stream protocol implemented by the core/novena FPGA build.

  • An implementation using the simpler interface implemented by the core/novena_i2c_simple environment.

  • An implementation using the coretest byt-stream protocol as implemented by the test/novena_trng FPGA build. This differs from the others in that it supports the Cryptech TRNG. Note that neither this HAL nor this FPGA build supports any cryptographic algorithms.

All of these HAL implementations are in the src/ directory. See the GNUmakefile for details on how to select the variant you want.

At present, the only relevant Cryptech cores are the TRNG and several digest algorithms. The current HAL uses the SHA-1, SHA-256, and SHA-512 cores to implement the SHA-1, SHA-256, SHA-384, and SHA-512 digests. SHA-512/224 and SHA-512/256 are not supported.

In principal there is no reason why one could not write a HAL which spoke to a Terasic board, perhaps via the coretest protocol over a UART, but to date this has not been done.

Code import status

Cryptlib itself is present in the repository in the form of a verbatim copy of the Cryptlib 3.4.2 distribution zipfile, which the top-level makefile unpacks while building. This has proven simpler to work with than importing the entire Cryptlib distribution into a vendor branch.

Packaging Cryptlib this way has two implications:

  • You may need to apt-get install unzip on your Novena.

  • Any changes you might make to Cryptlib itself will be lost when you run make clean.

Test code

The tests/ directory contains a few test scripts, written in Python, using the standard Cryptlib Python bindings. The Cryptlib Python environment is a fairly literaly translation of the Cryptlib C environment, so portions of it will be a bit, um, surprising to Python programmers, but the basic functionality works. Note that it's normal for test scripts to fail when the functionality they're testing isn't loaded on the FPGA.

Cryptlib itself is copyright by Peter Gutmann. See the Cryptlib web site for licensing details.

Code written for the Cryptech project is under the usual Cryptech BSD-style license.