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<p>Dear OpenSSL users,</p>
<p>I have a question about OpenSSL. Recently, I asked myself if
there was a maximum bit length for the modulus of a RSA key.</p>
<p>I tried to type :</p>
<p><font face="monospace">user@host:~$ openssl genrsa 32768<br>
Warning: It is not recommended to use more than 16384 bit for
RSA keys.<br>
Your key size is 32768! Larger key size may behave not
as expected.<br>
Generating RSA private key, 32768 bit long modulus (2 primes)</font></p>
<p>I got this warning, and I wonder why a larger key size may behave
not as expected.</p>
<p>Could anyone explain or give resources on why this doesn't work ?</p>
<p>My guess is that, having the following : (M = message, C =
Ciphered)<br>
</p>
<p><img src="cid:part1.73106852.AEBD042C@gwidmer.fr" alt=""></p>
<p>If M^e is < n, we could easily compute the original message ?</p>
<p>Also, I want to apologize if my question is redundant, I tried to
search on GitHub and through the mailing list, but there is no
search feature in the mailing list.</p>
<p>Have a nice day !</p>
<p>Grégory Widmer</p>
<p><br>
</p>
<p>PS : This question is for knowledge purpose only, I don't use RSA
keys anymore (except with GPG), I prefer ECC :)<br>
</p>
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