Re: Report of collision-generation with MD5

From: Mohacsi Janos (mohacsi_at_niif.hu)
Date: 08/26/04

  • Next message: Peter Jeremy: "Re: Report of collision-generation with MD5" 
    Date: Thu, 26 Aug 2004 09:34:26 +0200 (CEST)
To: Scott Gerhardt <scott@g-it.ca>

    On Wed, 25 Aug 2004, Scott Gerhardt wrote:

    >
    >>
    >> On 18-Aug-2004 Mike Tancsa wrote:
    >>> As I have no crypto background to evaluate some of the (potentially wild
    >>> and erroneous) claims being made in the popular press* (eg
    >>> http://news.com.com/2100-1002_3-5313655.html see quote below), one thing
    >>> that comes to mind is the safety of ports. If someone can pad an archive
    >>> to come up with the same MD5 hash, this would challenge the security of
    >>> the FreeBSD ports system no ?
    >>
    >> I _believe_ answer is "no", because i _think_ the FreeBSD ports system also
    >> verify the size of the archive(s) (cat /usr/ports/any/any/distinfo to see
    >> what made me think that).
    >>
    >> Padding would modify archive size. Finding a backdoored version that both
    >> satisfy producing the same hash and being the same size is probably not
    >> impossible, but how many years would it take ?
    >>
    >>
    >> Now, i may be wrong. Any enlightement welcome.
    >>
    >> --
    >> Guy
    >> _______________________________________________
    >>
    >
    > Why not adopt the OpenBSD method for ports. OpenBSD supplies 3 hash/digests
    > for downloaded binaries and sources. Those OpenBSD guys leave nothing to
    > chance.
    >
    > ports/databases/postgresql] scott% cat distinfo
    > MD5 (postgresql-7.3.5.tar.gz) = ef2751173050b97fad8592ce23525ddf
    > RMD160 (postgresql-7.3.5.tar.gz) = 83d5f713d7bfcf3ca57fb2bcc88d052982911d73
    > SHA1 (postgresql-7.3.5.tar.gz) = fbdab6ce38008a0e741f8b75e3b57633a36ff5ff

    I would also opt for having (by default) additional hash algorithms. I
    would prefer using method of NetBSD: using an external program called
    digest ( see security/digest port) to select the algorithms. Oliver
    Eikemeier is working a ports building infrastructure and I think it would
    be a good idea to this new infrastructure would support multiple hash
    algorithm. The most easiest way would be to define a knob like
    PREFERED_HASH that would list the algorithms that system would prefer,
    and REQUIRED_HASH that would be required to checked:
    - makesum should generate all the PREFERED_HASH
    - fetch should fail if any of the REQUIRED_HASH failed

    additional bit to NetBSD digest should be extended to have SIZE "hash" -
    this is only for simplification of bsd.port.mk rules.

    Today setup would be:
    PREFERED_HASH= MD5 SIZE
    REQUIRED_HASH= MD5 SIZE (except when NO_SIZE defined)

    Janos Mohacsi
    Network Engineer, Research Associate
    NIIF/HUNGARNET, HUNGARY
    Key 00F9AF98: 8645 1312 D249 471B DBAE 21A2 9F52 0D1F 00F9 AF98

    _______________________________________________
    freebsd-security@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-security
    To unsubscribe, send any mail to "freebsd-security-unsubscribe@freebsd.org"

  • Next message: Peter Jeremy: "Re: Report of collision-generation with MD5"

    Relevant Pages

    • Re: [Full-disclosure] Chinese Professor Cracks Fifth Data Security Algorithm (SHA-1)
      ... SHA-1 is 160 bit hash. ... MS> professor Wang Xiaoyun of Beijing's Tsinghua University and Shandong ... Wang's research focusses on hash algorithms. ...
      (Full-Disclosure)
    • Re: A different aproach to archiving files
      ... >> checking and throw out the modulo computation. ... >But that would result in the hash depending on only ... >> produce multiple small values from different algorithms, ... Depends on the hash algorithms. ...
      (comp.os.linux.development.apps)
    • Re: Uniqness of Hash Values
      ... >for duplicate files - but not quite). ... >How good are the hash algorithms for creating Unique references? ... bigger the key the less likely a dupe is but it will happen. ...
      (borland.public.delphi.non-technical)
    • Re: Lost password + MD5 ?
      ... For clarity's sake: I do not claim to be an encryption-expert. ... > Obviously different strings can create the same MD5 hash. ... > long as the data being encrypted (before any compression algorithms). ...
      (comp.lang.php)
    • Re: NSEC3, version 12,
      ... In section 12.1.3 ("Using New or Unknown Hash Algorithms"), ... Imagine a resolver that only supports NSEC3-SHA256 (or some other new ... but not NSEC3-SHA1 (or whatever the zone is currently ...
      (comp.protocols.dns.std)