2 bit prime, 2^-435 for a 1024 bit prime, 2^-648 for a 2048 bit prime, and lower than 2^-882 for primes larger than 2048 bit.</p>

<p>If <b>add</b> is <b>NULL</b> the returned prime number will have exact bit length <b>bits</b> with the top most two bits set.</p>

<p>If <b>ret</b> is not <b>NULL</b>, it will be used to store the number.</p>

<p>If <b>cb</b> is not <b>NULL</b>, it is used as follows:</p>

<ul>

<li><p><b>BN_GENCB_call(cb, 0, i)</b> is called after generating the i-th potential prime number.<