[{"data":1,"prerenderedAt":514},["ShallowReactive",2],{"project-7944540":3},{"id":4,"name":5,"line":6,"line_source":7,"title":8,"url":9,"domain":10,"maker":11,"posted_at":12,"year":13,"points":14,"comments":15,"rank_in_year":16,"shown_in_year":17,"top":18,"tier":19,"category":20,"subcategory":21,"format":22,"keywords":23,"reception":28,"sentiment":29,"stance_mix":30,"scored_comments":35,"aspects":36,"strip":51,"post_text":53,"what":54,"said":95,"maker_in_thread":211,"shape":224,"grid":228,"attempts":472,"same_week":477,"maker_shows":38,"maker_hidden":506,"reader_version":507,"card":508},"7944540","Hashcash","Replace CAPTCHA with Proof-of-Work","title","Show HN: Replace CAPTCHA with Proof-of-Work","https:\u002F\u002Fhashcash.io\u002F","hashcash.io","hippich",1403710066,2014,89,92,322,2272,15,"notable","security_privacy","spam prevention","web_app",[24,25,21,26,27],"captcha alternative","proof of work","hashcash","bot protection","roasted",-0.421,{"positive":31,"neutral":32,"mixed":33,"critical":34},9,17,2,33,61,{"idea":37,"performance":40,"design":42,"execution":45,"pricing":47,"privacy":49,"docs":50},{"positive":38,"critical":39},4,14,{"positive":33,"critical":41},8,{"positive":43,"critical":44},1,3,{"positive":43,"critical":46},6,{"positive":48,"critical":43},0,{"positive":48,"critical":43},{"positive":48,"critical":48},[43,48,43,44,43,43,43,43,44,43,44,43,52,43,43,43,52,52,52,38,43,52,43,44,52,43,43,43,43,43,43,48,43,44,44,44,43,44,43,43],5,null,{"problem":55,"audience":53,"pricing":53,"motivation":66,"time_to_build":53,"stack":70,"openness":93,"stage":94,"team_size":93},{"value":56,"source":57,"evidence":58},"CAPTCHAs are annoying for users and can be bypassed cheaply by spammers.","maker",[59,63],{"id":60,"by":61,"text":62},"7944730","buro9","This is the first CAPTCHA replacement that I really like. Adding a delay that costs computing power will both slow down and add real costs to spammers (though if it's a bot net…",{"id":64,"by":11,"text":65},"7944738","This was a reason I made this project. Thank you for great feedback! :)",{"value":67,"source":57,"evidence":68},"Make CAPTCHAs unnecessary by using computational work instead.",[69],{"id":64,"by":11,"text":65},[71,77,81,89],{"value":72,"source":57,"evidence":73},"JavaScript",[74],{"id":75,"by":11,"text":76},"7944827","I created jQuery plugin with that kind of widget, but really, any type of widget can be built on top of it. What jquery plugin does - used API library to communicate anyway, so…",{"value":78,"source":57,"evidence":79},"jQuery plugin",[80],{"id":75,"by":11,"text":76},{"value":82,"source":83,"evidence":84},"asm.js scrypt miner","commenter",[85],{"id":86,"by":87,"text":88},"7945707","thrwf34f33","To be precise, right now it uses Dogecoin proof of work. I got it running pretty good with asm.js compiled scrypt miner code. In future I will need to solve scaling problem, as…",{"value":90,"source":83,"evidence":91},"Dogecoin p2pool",[92],{"id":86,"by":87,"text":88},"unknown","beta",{"praise":96,"objections":111,"requests":158,"questions":176,"alternatives":188},[97,105],{"value":98,"source":83,"evidence":99},"Clever alternative to CAPTCHA that doesn't need human tests.",[100,104],{"id":101,"by":102,"text":103},"7944835","thibauts","Same here. First time in many years that I don't say to myself \"bullshit\" while looking at a purported solution to the captcha problem. The solution is at once obvious and very…",{"id":60,"by":61,"text":62},{"value":106,"source":83,"evidence":107},"Works on mobile and is a welcome CAPTCHA replacement.",[108],{"id":109,"by":61,"text":110},"7944788","I really like that it works fine on my mobile too. Have you done tests on many platforms to show which ones are supported? I'd probably like it to be more automatic... a single…",[112,123,133,144,151],{"value":113,"source":83,"evidence":114},"Botnets and spammers don't pay for CPU time, so the cost barrier is weak.",[115,119],{"id":116,"by":117,"text":118},"7945027","oliwarner","How does this stop spammers? Are they supposed to give up because it uses up too much time (and CPU and therefore electricity)? - Botnet operations are hacked PCs. They aren't…",{"id":120,"by":121,"text":122},"7945463","falcolas","> They aren't paying for CPU time. There's still an opportunity cost. Would they prefer to hit a service which limits their machines to a few thousand attempts per day, or a…",{"value":124,"source":83,"evidence":125},"Slow on phones and drains laptop batteries.",[126,130],{"id":127,"by":128,"text":129},"7946343","na85","On top of all this, the fact that hashcash requires the browser to \"work hard\" means that any website using it will heat up my laptop and drain its battery unnecessarily. Why is…",{"id":131,"by":128,"text":132},"7947338","My phone took 2 minutes to do the example one.",{"value":134,"source":83,"evidence":135},"GPU or native implementations would be much faster than JavaScript.",[136,140],{"id":137,"by":138,"text":139},"7947888","cyounkins","I think the same thing we saw at the beginning of bitcoin would happen here - a GPU implementation would be able to run hundreds of the proofs in parallel. Changing the…",{"id":141,"by":142,"text":143},"7948837","mtourne","I implemented a proof of work system to protect access to a large number of webpages before. The problem is that a native implementation is an order of magnitude faster than the…",{"value":145,"source":83,"evidence":146},"Hashcash.io becomes a third-party point of failure.",[147],{"id":148,"by":149,"text":150},"7948472","jlebar","This isn't a fundamental problem with the idea here, but one thing I don't like is that it makes hashcash.io a point of failure in your form submission. If the site goes down,…",{"value":152,"source":83,"evidence":153},"Cheap cloud servers make cracking economical.",[154],{"id":155,"by":156,"text":157},"7944814","viraptor","I really like the idea, but... I'm not sure it's possible to achieve right kind of cost balance here. Some assumptions at first: every device has to use the same work scaling…",[159,169],{"value":160,"source":83,"evidence":161},"Invite codes for early access.",[162,166],{"id":163,"by":164,"text":165},"7945311","jo_","Thank you for making it. (I'll beg you for an invite later.) I'd experimented with embedding Javascript Bitcoin miners in my website as a means of monetization without ads. I see…",{"id":167,"by":164,"text":168},"7946507","Woww. Such clever. Much compile. I've been trying to get Hamiyoca's JS miner to work with mupool without much success. (Stratum is straitforward. I'm just dumb.) p2pool is way…",{"value":170,"source":83,"evidence":171},"Automatic background calculation instead of manual trigger.",[172,173],{"id":109,"by":61,"text":110},{"id":174,"by":164,"text":175},"7945425","If you start calculating the hash in the background, that could be useful. I might not want to wait 100 seconds after I've finished my reply, but I don't imagine I'd mind waiting…",[177,181],{"value":178,"source":83,"evidence":179},"How does this stop spammers who use hacked machines?",[180],{"id":116,"by":117,"text":118},{"value":182,"source":83,"evidence":183},"What is the user experience?",[184],{"id":185,"by":186,"text":187},"7946107","pbreit","So what's the user experience??",[189,200,204],{"value":190,"source":83,"evidence":191},"Rate limiting by IP address.",[192,196],{"id":193,"by":194,"text":195},"7945243","vomitcuddle","As someone with experience in both implementing and bypassing spam protection, this idea makes no sense to me. Let's say it takes the user 30 seconds to calculate proof-of-work.…",{"id":197,"by":198,"text":199},"7949368","phantom784","What's the advantage of this versus just rate-limiting the number of requests per IP.",{"value":201,"source":83,"evidence":202},"Traditional CAPTCHAs.",[203],{"id":116,"by":117,"text":118},{"value":205,"source":83,"evidence":206},"Hashcash in SpamAssassin.",[207],{"id":208,"by":209,"text":210},"7946775","jlgaddis","Recent versions of SpamAssassin already include support for this and subtract (varying amounts of) points for e-mails containing valid Hashcash tokens.",{"comments":212,"answered":213,"key":214},12,7,[215,218,221],{"id":216,"text":217},"7946884","if you laptop solves this in 10 seconds and you need to post 10 messages a day, it is under 2 minutes of working hard for your laptop. I doubt it will make a dent in your battery…",{"id":219,"text":220},"7947454","I guess this would depend on how bad situation with spam is on specific site. Just like showing CAPTCHA only once you could do showing hashcash widget only once...",{"id":222,"text":223},"7944841","At least it is not fixed cost\u002Fcomplexity. If you see large number of attacks\u002Fspam, you response by increasing complexity (and cpu cycles required to solve it) And you remove…",{"commenters":225,"max_depth":46,"maker_replies":212,"first_comment_mins":226,"lifespan_hours":227},59,28,25,[229,231,235,238,239,243,245,249,252,255,257,261,263,264,268,271,274,277,279,281,285,289,290,291,293,294,297,300,303,306,309,310,312,314,317,319,321,324,326,329,330,332,334,336,337,338,340,342,344,345,347,350,354,357,361,365,367,370,371,374,377,380,383,385,388,391,393,397,400,402,405,409,411,415,418,422,424,428,433,435,438,441,443,447,449,453,456,458,460,462,465,469],[116,48,43,230,117,48],"project\u002Fcritical\u002Fidea",[232,48,48,233,234,48],"7945206","commenter\u002Fneutral\u002Fidea","tomjen3",[236,48,48,233,237,48],"7945399","opendais",[120,48,48,233,121,48],[240,48,44,241,242,48],"7945517","project\u002Fneutral\u002Fidea","bitJericho",[127,48,43,244,128,48],"project\u002Fcritical\u002Fperformance",[246,48,48,247,248,48],"7946823","commenter\u002Fneutral\u002Fnone","brokentone",[250,48,43,244,251,48],"7947135","beachwood23",[253,48,52,254,128,48],"7947339","project\u002Fpositive\u002Fperformance",[216,48,48,256,11,43],"project\u002Fneutral\u002Fperformance",[258,48,43,259,260,48],"7947307","project\u002Fcritical\u002Fdesign","ozten",[219,48,48,262,11,43],"project\u002Fneutral\u002Fdesign",[131,48,43,244,128,48],[265,48,43,266,267,48],"7947860","project\u002Fcritical\u002Fexecution","abhinavk",[269,48,48,233,270,48],"7947059","lmkg",[272,48,48,233,273,48],"7947581","comex",[275,48,43,230,276,48],"7947595","3pt14159",[278,48,48,233,273,48],"7947635",[280,48,48,247,149,48],"7948445",[282,48,44,283,284,48],"7948381","project\u002Fneutral\u002Fpricing","jsilence",[286,48,43,287,288,48],"7948440","project\u002Fcritical\u002Fpricing","rjaco31",[155,43,43,230,156,48],[222,43,48,241,11,43],[292,43,43,230,156,48],"7944872",[174,43,52,254,164,48],[295,43,43,230,296,48],"7945025","arh68",[298,43,43,244,299,48],"7945248","p8952",[301,43,44,256,302,48],"7945483","singlow",[304,43,52,305,299,48],"7945967","project\u002Fpositive\u002Fidea",[307,43,43,244,308,48],"7948585","troels",[193,33,43,230,194,48],[311,33,43,230,194,48],"7945402",[313,33,43,230,121,48],"7945429",[315,33,48,247,316,48],"7945563","danbruc",[318,33,48,247,121,48],"7946322",[320,33,43,230,194,48],"7946117",[322,33,48,323,242,48],"7945654","other\u002Fneutral\u002Fnone",[325,33,48,283,11,43],"7945909",[327,33,52,328,87,48],"7945719","project\u002Fpositive\u002Fexecution",[60,44,52,305,61,48],[64,44,48,331,11,43],"maker\u002Fneutral\u002Fnone",[109,44,52,333,61,48],"project\u002Fpositive\u002Fdesign",[75,44,48,335,11,43],"project\u002Fneutral\u002Fexecution",[163,44,44,283,164,48],[86,44,44,283,87,48],[167,44,52,339,164,48],"project\u002Fpositive\u002Fnone",[341,44,48,331,11,43],"7946981",[343,44,43,230,237,48],"7944825",[101,44,52,305,102,48],[346,38,44,241,302,48],"7945428",[348,38,44,241,349,48],"7945465","yid",[351,52,43,352,353,48],"7946808","project\u002Fcritical\u002Fprivacy","a1a",[355,52,48,356,11,43],"7946878","maker\u002Fneutral\u002Fdocs",[358,52,44,359,360,48],"7947308","project\u002Fneutral\u002Fprivacy","ars",[362,52,48,363,364,48],"7947324","commenter\u002Fneutral\u002Fprivacy","0x0",[366,46,44,241,121,48],"7945134",[368,213,52,305,369,48],"7947608","web007",[141,41,43,244,142,48],[372,31,43,266,373,48],"7944924","boredprogrammer",[375,31,43,266,376,48],"7945547","Sekhmet",[378,31,44,379,87,48],"7945702","maker\u002Fneutral\u002Fexecution",[381,31,43,266,382,48],"7946600","macNchz",[384,31,48,379,11,43],"7946677",[386,31,43,266,387,48],"7946859","bradjohnson",[389,31,43,266,390,48],"7950281","sjs382",[148,392,43,259,149,48],10,[394,395,44,241,396,48],"7948652",11,"carlob",[398,212,43,230,399,48],"7945837","homakov",[137,401,43,244,138,48],13,[403,39,43,230,404,48],"7946294","mappum",[406,18,48,407,408,48],"7945614","other\u002Fneutral\u002Fidea","lotsofmangos",[410,18,48,407,164,48],"7946555",[412,18,48,413,414,48],"7946700","commenter\u002Fcritical\u002Fidea","krapp",[416,18,48,407,417,48],"7947289","wmf",[419,420,43,230,421,48],"7947912",16,"Vanit",[423,420,48,230,11,43],"7948392",[425,32,44,426,427,48],"7946946","project\u002Fmixed\u002Fperformance","mikelat",[429,430,44,431,432,48],"7945179",18,"project\u002Fmixed\u002Fdesign","choonkeat",[434,430,44,356,87,48],"7945712",[436,437,48,323,87,48],"7945691",19,[439,437,48,323,440,48],"7945839","dang",[208,442,44,241,209,48],20,[444,445,43,259,446,48],"7947576",21,"TTPrograms",[448,445,48,356,11,43],"7947716",[450,451,44,241,452,48],"7944813",22,"muxxa",[454,451,44,335,455,48],"7944908","DominoTree",[457,451,48,356,11,43],"7947100",[185,459,44,262,186,48],23,[197,461,43,230,198,48],24,[463,227,43,244,464,48],"7946641","nijiko",[466,467,44,241,468,48],"7944948",26,"gd1",[470,467,48,233,471,48],"7945054","lauradhamilton",[473,474],{"id":4,"t":12,"points":14,"comments":15},{"id":475,"t":476,"points":38,"comments":43},"10135852",1440774846,[478,483,488,493,498,502],{"id":479,"name":480,"points":481,"category":482},"7937258","Fast.js",323,"languages",{"id":484,"name":485,"points":486,"category":487},"7926005","Scholar Ninja",98,"learning_science",{"id":489,"name":490,"points":491,"category":492},"7940030","Seed-DB funding visualization",85,"data",{"id":494,"name":495,"points":496,"category":497},"7937476","Checkr.io",79,"web_saas",{"id":499,"name":500,"points":501,"category":497},"7917408","BillForward",73,{"id":503,"name":504,"points":505,"category":492},"7931659","SeeYourVisitors",69,false,"v2",{"id":509,"name":5,"line":6,"ai":506,"cat":20,"year":13,"points":14,"comments":15,"rec":28,"s":510,"top":18,"kw":511,"maker":11,"domain":10,"tier":19,"attempts":33,"strip":512,"url":9,"mix":513,"praise":98,"objection":113,"sub":21},7944540,-0.42,[24,25,21,26,27],"1013111131315111555415135111111013331311",[31,32,33,34],1793990906960]