On 20 January 2017 at 14:36, Dirk-Willem van Gulik <di...@webweaving.org> wrote: > On 20 Jan 2017, at 13:00, Ben Laurie <b...@links.org> wrote: > >> Why do you need the obsolete hash functions? > > I am still in the middle of some inventory work with the help of a few > friendly enterprise & cloud folks. > > But it is nog looking good -- so far its seems that: > > - md4 is rarely used (i,e.a actually called). > > - md5 is very often used for > - salted password > - creating all sorts of unguessable IDs. > - generation of a randomish token/digest > - creating/protecting session cookies > - creating 12/23/34/1221231.txt file trees or similar equal wear file > / tmp file fanout. > - checksumming a file along the lines of taking an fstat() snapshot. > - commonly used UUID gen. > - content-digest generation for things like cache headers, imap/sieve > breakout. > - file integrity. > > - sha1 is used a factor 10x less. Mostly: > - salted password > - creating/protecting session cookies > > - sha256 && 512 seems to be used about as often md4. > > Though nothing stopping us from having a snotty warning/#define to discourage > use - and wack the 60 or so distinct places/ where MD5 is currently used in > subversion/httpd and friends and upping this to at least sha256. > > I guess cryptographically there is little point between an MD5 and the last > 16 bytes of a SHA256 ? Correct ?
Not sure what question you're asking? > > As in a lot of above case - the MD5 is not exposed - does not actually need > to be an MD5 for interoperability purposes. > > > Dw. > >
