Last week , I posed thischallenge : You and nine of your coworkers are sitting in a league way when somebody wonders loud about the group ’s modal salary . Everyone is curious , but nobody feels comfortable sharing their own pay with the group . How can you all learn your average remuneration without anybody learn any more entropy about another soul ’s pay ( other than what can be deduced from the group average ) ? You all have pen and report and can conceal what you write from others , but you have no other tools at your garbage disposal . You may assume that everybody cooperates with the pick out strategy .
Solution to Puzzle #23: Money Secrets
Number the ten people from 1 to 10 . Person one call back of a random turn . It can be positive or disconfirming , but should be magnanimous in order of magnitude . Call the random number gas constant , and the salary s1 , s2 , … , s10 . Person one adds their personal salary to their choose turn ( gas constant + s1 ) , writes down the result , and slides it upside down to person two .
Notice that by looking at the result of universal gas constant + s1 , person two read nothing about person one ’s remuneration . If they received some random - see negative 37 - figure act , how could they derive what part of it is r and what part is s1 ?
Person two then lend their earnings to the act they take in from person one ( give roentgen + s1 + s2 ) , writes down the resolution , and slides it front down to person three . Again , person three learns nothing about the old remuneration . They did n’t see r + s1 , they only see universal gas constant + s1 + s2 , which looks just as random to them as universal gas constant itself would .
This outgrowth remain around the lot until the paper returns to person one , now incorporate radius + s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10 .
Person one then deduct gas constant from the sum , yielding just the sum of everybody ’s wage . They divide this by ten and report the norm to the group .
Random number play an crucial role in digital security and privacy in much the same agency that they do in this puzzle . arbitrarily generate numbers can obscure tender selective information in sophisticated ways and allow researchers to rigorously try out properties of their data point - protection system of rules .
Recruitment
Daily Newsletter
Get the best technical school , science , and finish tidings in your inbox daily .
news program from the future , delivered to your present .
You May Also Like
