&gt;&gt;[...] others in the cryptographic community [built] what they called &#x27;fair&#x27; blind signatures [...] where untraceability could be lifted by an &quot;independent party posessing the right private key&quot; (i.e. a public &quot;police backdoor&quot;). They were trying to backdoor Chaum&#x27;s encryption...<p>Chaum himself is advocating not just for any ol&#x27; backdoor, but for a flavour of &quot;multi-sovereign-party public police backdoor&quot; if you believe the Wired article that explained his proposal.[1]<p>[1] <a href="http:&#x2F;&#x2F;www.wired.com&#x2F;2016&#x2F;01&#x2F;david-chaum-father-of-online-anonymity-plan-to-end-the-crypto-wars&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.wired.com&#x2F;2016&#x2F;01&#x2F;david-chaum-father-of-online-an...</a>