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    No, because bcrypt randomly generates a salt and stores it in the
    password hash. So you can only compare given plaintext against a
    specific, already-existing hash.<br>
    <br>
    --Casey<br>
    <br>
    On 2/8/2012 3:40 PM, Shannon Lee wrote:
    <blockquote
cite="mid:CAGjxht=tLp-GqZCQUsPc+NX+Kcp2tJEpP1QeFHQMpv4FuNgncg@mail.gmail.com"
      type="cite">If you have an index if bcrypt'd phone numbers, you
      can simply bcrypt the incoming number and search the index for
      that hash, yes?
      <div><br>
      </div>
      <div>--S<br>
        <br>
        <div class="gmail_quote">On Wed, Feb 8, 2012 at 3:38 PM, Casey
          Callendrello <span dir="ltr">&lt;<a moz-do-not-send="true"
              href="mailto:c1@caseyc.net">c1@caseyc.net</a>&gt;</span>
          wrote:<br>
          <blockquote class="gmail_quote" style="margin:0 0 0
            .8ex;border-left:1px #ccc solid;padding-left:1ex">
            <div class="im">On 2/8/2012 1:39 PM, Jonathan Lassoff wrote:<br>
              &gt; Perhaps bcrypt the phone number and store that
              instead? That way, you<br>
              &gt; can verify that something's in there, but it can't be
              easily figured<br>
              &gt; out what it is.<br>
              <br>
            </div>
            I'd thought about that. However, when a user dials in, we
            don't know<br>
            their username, so we have to just test their<br>
            "password" (the phone number) against every known entry. If
            the number<br>
            of bcrypt rounds is too high, then it takes forever. Is
            there a hashing<br>
            function I should choose that is efficient but will make
            just<br>
            enumerating all passwords too slow? There are about
            2360000000 possible<br>
            north-american phone numbers based on currently-allocated
            area codes.<br>
            <br>
            I suppose bcrypt will be fine provided that all possible
            numbers can be<br>
            quickly scanned.<br>
            <font color="#888888"><br>
              -c.<br>
            </font>
            <div>
              <div class="h5"><br>
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              </div>
            </div>
          </blockquote>
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        <br>
        <br clear="all">
        <div><br>
        </div>
        -- <br>
        Shannon Lee<br>
        (503) 539-3700<br>
        <br>
        "Any sufficiently analyzed magic is indistinguishable from
        science."<br>
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