Thursday, August 4, 2016

John the Ripper GPU support

  • Latest release include more formats and latest git trees include even more.
  • CUDA significantly benefits from compile-time tuning of parameters for a given GPU, see doc/README-CUDA
  • sha512crypt is currently faster on NVIDIA than on AMD/ATI, and moreover the OpenCL code is currently faster than CUDA (unusual)
  • bcrypt is sort of supposed to be inefficient on GPU, so it achieves at best CPU-like performance currently (yet you do get the option to put your many GPUs to at least some reasonable use if you only have bcrypt hashes to attack)
  • WPA-PSK CUDA uses a little bit of CPU code as well, and benefits from OpenMP (so you'll get slightly faster speed if you enable OpenMP in the JtR build, although you'll load multiple CPU cores then). The OpenCL version has post-processing on GPU too so doesn't use much CPU resources and will not benefit from OpenMP.
  • RAR is a mix of CPU and GPU code, with the ratio varying widely between different RAR archives (type, size). Later versions has mature “early reject” code that minimizes this.
     
  • http://openwall.info/wiki/john/GPU 

Cielo e terra (duet with Dante Thomas)