COSICOIN

Programming Library Prerequisites

Requires a C++17 or higher version.

• gRPC: https://grpc.io/

• gTest: https://github.com/google/googletest

• gLog: https://github.com/google/glog

• the sha256 implementation: https://github.com/stbrumme/hash-library

• nlohmann JSON: https://github.com/nlohmann/json

Building the code

Execute the following four commands to build and test the code locally.

mkdir -p cmake/build
pushd cmake/build
cmake -DCMAKE_PREFIX_PATH=/freeware/grpc-1.34 ../..
make -j 4
ctest

Note: this code assumes the GRPC install directory is in $HOME/.local!

Note: the build.sh script runs those commands at once.

Cross compiling the code on FPGA boards

Execute the cross-build.sh script to cross compile for the PYNQ boards.

The executables

After building the following executables are made:

• server_client_test (tests simple localhost server client communication)
• node_test_ex (tests consensus protocol locally)
• hash_test_ex (tests calculating hash using hardware, has to be run with sudo on the board)
• hash_timings (compares the running time of calculating a hash in software or hardware, has to be run with sudo on the board)
• demo (runs a full demo locally)

The demo runs correctly until the verifying stage. That means the consensus is reached but because of some unsolved exception the block is never added to the blockchain and thus the utxolist is not updated.

Executing on Software

cd to cmake/build and run the executables defined in the src directory.

cd to cmake/build and run the test scripts with ctest.

Hardware

To run the hardware the bitstream must first be flashed on the fpga. This can be done by putting the files hw.bit.bin and fpgautils on the board, and running the following 3 commands:

sudo chown –R xilinx:xilinx ./*
sudo chmod +x fpgautils
sudo ./fpgautil -b hw.bit.bin -f Full

Now the FPGA is programmed correctly and ready to calculate some hashes

The hardware can also be tested seperately by running cmake . and make. The source code of the executionable can be found in main.c The block has to be initialised manually and the num_blocks should be zero if only one sha256 must be computed and one if two cycles are needed. To run the executionable you can use the following command:

sudo ./main

The files that were not written by us are fpgautils and the converter from a bitstream.bit to a bistream.bit.bin. All the other files in the folder verilog_code are written by us.

The modified verilog files are also provided. They can be placed directly in the interface of DDP.

TODO

logging module(glog) unavailable for cross-compiling

database employment

transaction input corner test(signed integer forbidden)