16 lines
674 B
Markdown
16 lines
674 B
Markdown
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A common security method used for online banking is to ask the user for three random characters from a passcode.
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For example, if the passcode was 531278, they may ask for the 2nd, 3rd, and 5th characters;
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the expected reply would be: 317.
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The text file, keylog.txt, contains fifty successful login attempts.
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~~~
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319 680 180 690 129 620 762 689 762 318
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368 710 720 710 629 168 160 689 716 731
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736 729 316 729 729 710 769 290 719 680
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318 389 162 289 162 718 729 319 790 680
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890 362 319 760 316 729 380 319 728 716
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~~~
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Given that the three characters are always asked for in order,
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analyse the file so as to determine the shortest possible secret passcode of unknown length.
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