<p>When the National Security Agency's invincible code-breaking machine encounters a mysterious code it cannot break, the agency calls in its head cryptographer, Susan Fletcher, a brilliant, beautiful mathematician.<br /> <a href="https://kevquirk.com/blog/digital-fortress" target="_blank" rel="nofollow noopener noreferrer" translate="no"><span class="invisible">https://</span><span class="ellipsis">kevquirk.com/blog/digital-fort</span><span class="invisible">ress</span></a></p>
