I have to way 1 hour to answer to your last MP
It's time for me to go to sleep.
See you

I tried this. ~same performance as the multiplication by P (for secpk1) for mmult  can be reduced in a single 64bit mult. So I'm interested in c.
OK, on linux, performace are still bad, i'm sorry. Some problem with intrinsic....

Linux or windows ?
Is it open source ? Can i try it ?

A group size of 512 does not bring significant improvement (less than 1%). The DRS62 ModInv is fast and almost negligible with a group size of 256.
If you have a modular mult faster than the digit serial Montgomery mult on a 256bit field, I'm obviously fully open. A folding does not improve thing on 256 bit when working with 64bit digits. I'm not sure if Barrett could be faster, I must say I didn't try and for "medium size field", there can be traps.

Hello,

Some news:
I just published (1.4) a new release with few fixes (especially for Linux) but the un-initialized memory bug may also affect Windows (I didn't manage to reproduced this bug on Windows but it can be random).

I managed to get back an old PC from my company (~8 years old) with 2 Quadro 600 inside
Unfortunately the Quadro 600 (fermi) has only compute capability 2.1 and I will have to set-up CUDA SDK 8.0 (the last one which supports fermi). I set up Ubuntu on this PC and I will try to develop the multi GPU release under Linux.
Hope I will manage to get good drivers for the Quadro 600 and to make it work.

Hello,

Affine coordinates for search (faster):
Each group perform p = startP + i*G, i in [1..group_size] where i*G is a pre-computed table containing G,2G,3G,.... in affine coordinates. The inversion of deltax (dx1-dx2) is done once per group (1 ModInv and 256*3 mult). group_size is 256 key long.

Protective coordinates for EC multiplication (computation of starting keys). Normalization of the key is done after the multiplication for starting key.

Edit:
You also may have noticed that I have an innovative implementation of modular inversion (DRS62) which is almost 2 times faster than the Montgomery one. Some benchmark and comments are available in IntMop.cpp.

Hello,
No problem.
Done

I just compiled this tool and I reach ~15MKey/sec on my hardware using compressed key only (after playing a bit with options to find optimal setting).
I reach ~25MKey/sec with VanitySearch using compressed key.
First I think that trying to brute forcing bitcoin addresses is utopian and the performance seems far from optimal...
https://github.com/JeanLucPons/VanitySearch

Hello,

I published a new release (1.3) with a ~15% global performance increase, (~20% on GPU).
On my hardware, VanitySearch is now 2 times faster (GPU) than oclvanitygen.
My goal was to reach a 8 characters (case sensitive) prefix in a reasonable time on my 6 years old hardware, it still need 2 weeks of computation for a 50% probability.
I'm not sure I will reach my goal of 2 or 3 days without changing my hardware
The next step will be to handle multiple GPU and to support CUDA for linux.

Hello,
If you want to attack SecpK1 key you'd better try Pollard rho on "reused" addresses (you can get the public key coordinates). It will drastically improve your chance of finding the private key but will nevertheless remains very unlikely.
The technique is very well described here: https://arxiv.org/ftp/arxiv/papers/1607/1607.05901.pdf

Hello,

Thank you for your interest and for reporting issues

I just published a new release (v1.2):
-Updated probability calculation for very large prefix
-Avoid that default configuration hangs the system when gpu is enabled
-Performance increase (~10%)

Thanks for testing 
The 2 "Check" fields are here especially for debugging/checking purposes. The 2 'checked' addresses are recomputed from the private key by a direct multiplication. To reach the desired address, during the search, generator points are added one by one.
You're right by default, if you just add the -gpu option, all CPU cores are used and it slows down much the system and even the GPU. The CPU cannot handle GPU/CPU transfer efficiently. I wrote few words about this on the README but I will let one CPU core free if the gpu is selected.

Hello 

I've just published a new release. There is also a makefile for Linux but it supports only CPU release. CUDA release for Linux is coming. I'm very interested in knowing performance you get on your hardware (Linux/Windows/CPU/GPU).

Thanks for testing and reporting issues.

Yes,
For the CPU code it should not be a problem unless some intrinsics are missing with gcc. I have to check.
Concerning CUDA, I have to install the Cuda SDK on a Linux machine and try to compile, that should not be a big deal.
There is only few Windows specific functions (concerning high resolution timer) but I can easily make a linux code for it using gettimeofday().
I let you informed.

Hello,

I would like to present a new bitcoin prefix address finder called VanitySearch. It is very similar to Vanitygen.
The main differences with Vanitygen are that VanitySearch is not using the heavy OpenSSL for CPU calculation and that the kernel is written in Cuda in order to take full advantage of inline PTX assembly.
On my Intel Core i7-4770, VanitySearch runs ~4 times faster than vanitygen64. (1.32 Mkey/s -> 5.27  MK/s)
On my  GeForce GTX 645, VanitySearch runs ~1.5 times faster than oclvanitygen. (9.26 Mkey/s -> 14.548 MK/s)
If you want to compare VanitySearch and Vanitygen result, use the -u option for searching uncompressed address.
VanitySearch may not compute a good gridsize for your GPU, so make several tries using -g options in order to find best performances.
Using compressed addresses is roughly 20% faster.

VanitySearch is available from https://github.com/JeanLucPons/VanitySearch

Benchmarks for various hardware (By DaveF):
https://bitcointalk.org/index.php?topic=5112311.msg50823897#msg50823897

There is still lots of improvement to do.
Feel free to test it and to submit issue.

Thanks.
Sorry for my bad English.
Jean-Luc