{"id":4,"date":"2007-08-11T18:19:16","date_gmt":"2007-08-11T23:19:16","guid":{"rendered":"http:\/\/arxiv.justinmullins.com\/?p=4"},"modified":"2007-08-15T04:43:00","modified_gmt":"2007-08-15T09:43:00","slug":"a-loophole-in-quantum-cryptography","status":"publish","type":"post","link":"http:\/\/arxivblog.com\/?p=4","title":{"rendered":"A loophole in quantum cryptography"},"content":{"rendered":"

I ain’t gonna stick my neck out on this but Peter “Raptor” Rapcan has something a-boilin and a-bubblin over at the Slovak Academy of Sciences <\/a>which could send all youse quantum cryptographers a-scuttlin back to your theory books.<\/p>\n

When ya’ll measure the state of a quantum particle, I betcha that ya’ll expect the information about that state to be destroyed by the process of measurement. But Raptor Rapcan ain’t so sure.<\/p>\n

His thinkin goes like this. All the information about the particle is stored in the wavefunction. But there are well established ideas about how much information a single measurement can extract from a wave-function–and it ain’t much. Could a second observer extract more about the original state?<\/p>\n

Raptor Rapcan and his Slovak buddies seem to think so and suggest this could compromise the security of any information sent in this way.<\/p>\n

In the paper, “Recycling of quantum information: Multiple observations of quantum systems<\/em><\/a>” they investigate the amount of information that can be extracted from a quantum system by a sequence of observers who are not allowed to communicate.<\/p>\n

And to cut a long story short, Raptor says that when measured like this, quantum information stored in an ensemble of quantum particles behaves classically.<\/p>\n

Woah–classically! I guess that’s gonna change the goalposts in the micro v macroscopic physics stakes. Ya’ll know how secure classical information is-right? This is gonna leave a few cryptos a-sweatin and a-mumblin.<\/p>\n

Reference: arxiv.org\/abs\/0708.1086<\/a>: Recycling of Quantum Information: Multiple Observations of Quantum Systems<\/p>\n","protected":false},"excerpt":{"rendered":"

I ain’t gonna stick my neck out on this but Peter “Raptor” Rapcan has something a-boilin and a-bubblin over at the Slovak Academy of Sciences which could send all youse quantum cryptographers a-scuttlin back to your theory books. When ya’ll measure the state of a quantum particle, I betcha that ya’ll expect the information about […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-4","post","type-post","status-publish","format-standard","hentry","category-secrets"],"_links":{"self":[{"href":"http:\/\/arxivblog.com\/index.php?rest_route=\/wp\/v2\/posts\/4","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/arxivblog.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/arxivblog.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/arxivblog.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/arxivblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4"}],"version-history":[{"count":0,"href":"http:\/\/arxivblog.com\/index.php?rest_route=\/wp\/v2\/posts\/4\/revisions"}],"wp:attachment":[{"href":"http:\/\/arxivblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/arxivblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/arxivblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}