Greg Boyd's contribution was a welcome one. I have two comments about it.
First, the performance white papers are 'ivory tower' only in the sense that their tone is formal and academic; their substance is severely practical. Second, the point that large block sizes are better than small ones has the same element of surprise that would attach to a resolute declaration that the earth is in fact an oblate spheroid, i.e., not flat; but it was clearly necessary to make it. John Gilmore, Ashland, MA 01721 - USA On 7/8/12, Greg Boyd <bo...@us.ibm.com> wrote: > Replying again to finish the last sentence! > > > I'll point you to the IBM Crypto performance whitepapers, available at > www.ibm.com/systems/z/advantages/security/z10cryptography.html. (Look on > the right under 'Learn More' for your machine type.) The numbers are very > ivory tower, and your mileage will vary, however, you can use these numbers > to compare clear key, secure key and protected key. > > Rob: Protected key does rely on one trip to the Crpyto Express card. Since > a protected key begins life as a secure key, the operational key must first > be decrypted from under the master key (inside the CEX3) but then it is > wrapped using the wrapping key. That operational key is then unwrapped > inside the CPACF hardware. > > And as Phil and Rob point out, blocking can have a significnat impact on > performance. That's easy to see in the white papers too since they provide > results for various blocksizes. The crypto hardware (both CPACF and CEX > card) is designed to handle large blocks of data and you'll get the best > throughput with large blocks. So your application design can have a major > impact on your performance. > > Greg Boyd > IBM Advanced Technical Support > Supporting Crypto on System z > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
