&gt; Now it&#x27;s three months since the post and nobody has pointed out the error, despite Reddit math being a self-selected crowd with a specific interest in the topic.<p>&#x2F;u&#x2F;GemOfEvan pointed out the error in the second highest (sorted by &quot;Best&quot;) reply:<p><pre><code>  I think I&#x27;m missing something. Alice has a message m and a
  product of primes a. She sends Bob the product ma. Bob has
  the product of primes b and sends back the product mab.
  Alice divides by a and sends back mb. Eve has heard the
  products ma, mab, and mb. (ma)(mb)&#x2F;(mab) = m, so Eve now
  has the message.
</code></pre>
Glancing through the other replies, I see at least a half dozen others also pointing out the problem, and also several explaining what it takes to make this kind of three way exchange actually work.<p>Reddit only reports timestamps to the month on articles this old, but all the replies I mention above say &quot;3 months ago&quot;.