I do think that the breakage of srand($seed) between 5.20 and earlier perls should have been spelled out in the srand documentation ... probably worth a bug report from someone who cares.

As documented in the 5.20 delta:

rand now uses a consistent random number generator Previously perl would use a platform specific random number generator, varying between the libc rand(), random() or drand48(). This meant that the quality of perl's random numbers would vary from platform to platform, from the 15 bits of rand() on Windows to 48-bits on POSIX platforms such as Linux with drand48(). Perl now uses its own internal drand48() implementation on all platforms. This does not make perl's rand cryptographically secure.

The effect of srand was platform specific. Ie different between Windows & *nix. And that is the cause of the failures for the obfu.

From 5.20 on, that problem goes away because of the built-in rand/srand rather inheriting them from the platform C compiler implementation.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^7: Late PM, 12/24/2014 & all year long by BrowserUk
in thread Late PM, 12/24/2014 & all year long by ww

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.