I got an NVIDIA 1070 and wanted to use it for somthing other than gaming. So I started learned CUDA programming. There was a hashing competition in an xkcd a while ago, so I thought I'd see how well I could do. I implemented the skein hash algorithm from the specification in this document.
While I have compile-time options to change the skein internal block size. I have only tested any of this code in skein 1024x1024 mode. I would expect skein 1024x? to work for any ?.
I may have the rotation constants or permutation functions wrong for skein 256x? and/or skein 512x?.
Also, I implemented this without any concern for security, so it's probably vulnerable to timing attacks and other such side channel attacks.
- Threefish block cipher
- UBI chaining mode
- Skein hashing
- C search
- GPU search
- Generating random data in each GPU thread, so I don't have to allocate ~6GiB of graphics memory.
- Command line options for CUDA kernel launch sizes.
- GPU threads using different lengths of the same random data.
- Sequential brute-force mode, as opposed to the random data, I'm using now.