People have been coming up with and breaking codes for thousands of years. The Caesar Cipher is not named such just because of some fascination with ancient Rome, for example.<p>One-time pads have been around for more than a century. Book ciphers can be quite secure and are centuries old. Criminals have been substituting phrases (e.g. &quot;I gave the flowers to Wanda&quot; -&gt; &quot;I murdered Bob the Snitch&quot;) since they&#x27;ve been aware they might be eavesdropped upon.<p>It has pretty much always been the case that you can encrypt your correspondence <i>if you wish</i> and then the state can attempt to read it anyway <i>if they wish</i>, and in states which require this sort of thing, if they can get a warrant.<p>Encrypting your correspondence has gotten easier. Nobody would have bothered to use a good cipher for &quot;Don&#x27;t forget to get eggs at the store&quot; (meaning, actually get eggs, not some substitute phrase for &quot;murder Bob the Snitch&quot;) twenty years ago, but now we do it all the time.<p>But that doesn&#x27;t change a whole lot. Criminals who gave a shit about not being spied upon have always had ways to ensure it couldn&#x27;t happen.