On Mon, 3 Dec 2007 12:58:53 -0600, Patrick O'Keefe <[EMAIL PROTECTED]> wrote:
>Is there any doc comparing performance of crypto functions using >the encryption hardware vs the same functions using software? > >I've seen a paper showing the performance of both CPACF and CEX2 >based on block sizes (very big differences) but not compared to >with software-only. I've also seen a z/Linux-oriented paper >supposedly showing software vs hardware performance, but not >showing any effect of message size reported in the other paper >so I'm a bit suspicious of its validity. > >Pat O'Keefe > > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO >Search the archives at http://bama.ua.edu/archives/ibm-main.html There is no official paper, but if you look at empirical data, software encryption for short texts (say in the area of 100 or so bytes) is "faster", but over that length or so, hardware just flies. Has to do with the time taken to "prime" the hardware, set up the key values, then do the work, Doing the work is relatively short with respect to priming the hardware. This is true for the CEX2 which processes keys that are already encrypted (hardware need to decrypt these before work begins). Fo CPACF, is is a single OP code so beats software routines thousands to one (TDES ASM routine has thousands of instructions). ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
