Greetings, keepers of knowledge.

I'm putting together a password checking script for Asterisk voicemail; one of the things I want to disallow is the use of a password that's got too many consecutive digits. "1234" being the classic example, but also "298761" or "4562".

PHP is my usual language, but it's not available, so I went with Perl, since I used it many years ago, and the two share a lot of common syntax. The code I have works, but I feel like there should be a better way, that doesn't take so many lines of code to go through every digit twice.

    my $password = $2;
    my $limit = 3; # want to reject 4568 but not 4578

    my $counter = 0;
    my $i = 0;
    my @digits = split(//, $password);
    my $pwlength = @digits;

    for ($i = 0; $i < $pwlength - 1; $i++) {
        if ($digits[$i] + 1 == $digits[$i + 1]) {
            $counter += 1;
        } else {
            $counter = 0;
        }
        if ($counter >= $limit) {
            exit 1;
        }
    }

    $counter = 0;
    for ($i = 0; $i < $pwlength - 1; $i++) {
        if ($digits[$i] - 1 == $digits[$i + 1]) {
            $counter += 1;
        } else {
            $counter = 0;
        }
        if ($counter >= $limit) {
            exit 1;
        }
    }

[download]

In reply to Check a string for consecutive digits by Anonymous Monk

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.