I'm always curious to hear where HashClash is used for! (@realhashbreaker on Twitter or let me know via Issues)

If you like HashClash and use it more often then please consider becoming a sponsor.

• C++11 compiler (e.g. g++)

• make

• autoconf & automake & libtool

  sudo apt-get install autoconf automake libtool

• zlib & bzip2 libraries

  sudo apt-get install zlib1g-dev libbz2-dev

• Optional: CUDA

• Run build.sh script

  ./build.sh

• Create temporary working directory (in top directory)

  mkdir cpc_workdir

  cd cpc_workdir

• Run script

  ../scripts/cpc.sh <prefix.filename1> <prefix.filename2>

• Create temporary working directory

  mkdir ipc_workdir

  cd ipc_workdir

• Run script

  echo -n "TEST" > prefix.txt

  ../scripts/poc_no.sh prefix.txt

  Note: the prefix file is expected to be a multiple of 64 bytes and optionally plus a small multiple of 4 bytes. These last bytes will be used as forced message words in steps of 4 bytes inside the first near-collision block. Any remaining 1, 2 or 3 bytes of the prefix file are ignored.

  Note: the first time the script is run it will be slower as it needs to create the 'upper' differential path set for the first time.

• Example output:

$ xxd collision1.bin
0000000: 5445 5354 1789 6de2 c568 339d 8bbf 6269  TEST..m..h3...bi
0000010: 563a c4ab 2fba 7aba 6ec7 e182 8566 8883  V:../.z.n....f..
0000020: b0f2 d716 17d5 8f97 b244 b9ca dcaa af93  .........D......
0000030: 3a33 4552 a9fd 023b 7012 7e5c d644 9646  :3ER...;p.~\.D.F
0000040: 723e 737a 6c3a 66e5 5d51 8e7c 7bc2 ec4f  r>szl:f.]Q.|{..O
0000050: 95a2 349f 0f4b 2540 cbe6 5644 d113 104b  ..4..K%@..VD...K
0000060: 5c39 898d f19a f9e9 e2aa bbad e191 d2d3  \9..............
0000070: a25d 4df0 9058 a873 4ee8 9dc9 47a5 281c  .]M..X.sN...G.(.

• Make your own attack

  Inside poc_no.sh there are three examples of identical-prefix collision attacks, selected by N=1, 2 or 3. You can add your own choice of message word differences here and see if you can make your own collision attack!

• Example:

md5("TEXTCOLLBYfGiJUETHQ4hAcKSMd5zYpgqf1YRDhkmxHkhPWptrkoyz28wnI9V0aHeAuaKnak")
=
md5("TEXTCOLLBYfGiJUETHQ4hEcKSMd5zYpgqf1YRDhkmxHkhPWptrkoyz28wnI9V0aHeAuaKnak")

• Create temporary working directory

  mkdir textcoll_workdir

  cd textcoll_workdir

• Run script

  ../scripts/textcoll.sh

• Edit the script for more options: change alphabet, force specific bytes, etc...