1. Yes, exactly. This is why we generate the hash on the EBCDIC version on z/OS and send it in FTP binary to the distributed FTP server. They then do the MD5 on this same (EBCDIC) data to verify the entire file was received.
2. Good point. I don't know if the hash requirement is simply to make sure the full file was received on the z/OS -> FTP server step, or if there is something beyond that. I will ask. I'm not really on the project; I've just been asked to make some recommendations regarding issues they are having. Thanks, Frank ________________________________ From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of Pew, Curtis G <curtis....@austin.utexas.edu> Sent: Friday, June 23, 2017 6:48 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: EBCDIC, ASCII, ugh On Jun 22, 2017, at 6:15 PM, Frank Swarbrick <frank.swarbr...@outlook.com> wrote: > > The MD5 is used to verify that the file sent from the mainframe has the same > data when received on the interim distributed system. So creating the MD5 > after its already there does no good. I will just add 2 points: 1. If you compute the MD5 hash while the file is still EBCDIC, you will get a completely different value than the hash of the ASCII version. Hash algorithms work on the binary representation, not the logical meaning. 2. If you’re trying to ensure the data hasn’t been intentionally modified, MD5 is nearly useless. If you need a hash for detecting malicious corruption, I’d use at least SHA2. -- Pew, Curtis G curtis....@austin.utexas.edu ITS Systems/Core/Administrative Services ---------------------------------------------------------------------- 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
