I am out of my element here, but my understanding is that since the key is equal in length to the message, there is no way for you to know whether you are simply seeing a pattern in the key or a pattern in the message.<p>Imagine a one time pad made for encoding numbers that used a &quot;MOD 10&quot; operation on each digit.<p>Then imagine the key is:<p><pre><code>    6926560279774
</code></pre>
And the message is:<p><pre><code>    0000000000000
</code></pre>
The output is:<p><pre><code>    6926560279774
</code></pre>
Alternative messages:<p><pre><code>    1234567890123 -&gt; 7150027069897
    1111111111111 -&gt; 7037671370885
</code></pre>
In all cases, the patterns that you can discern <i>may</i> be from my message and <i>may</i> be from the key.  As an analyst, you can&#x27;t tell.<p>If this were English letters rather than numbers, and you know &#x27;e&#x27; is very common, you still can&#x27;t get anywhere because each &#x27;e&#x27; is encoded with a unique character from the key.