22afc2a0ca
Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com> Co-authored-by: Kristofer Koishigawa <scissorsneedfoodtoo@gmail.com> Co-authored-by: Beau Carnes <beaucarnes@gmail.com>
73 lines
1.6 KiB
Markdown
73 lines
1.6 KiB
Markdown
---
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id: 5900f3bb1000cf542c50fece
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challengeType: 5
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isHidden: false
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title: 'Problem 79: Passcode derivation'
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forumTopicId: 302192
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---
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## Description
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<section id='description'>
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A common security method used for online banking is to ask the user for three random characters from a passcode. For example, if the passcode was 531278, they may ask for the 2nd, 3rd, and 5th characters; the expected reply would be: 317.
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The array, `keylog`, contains fifty successful login attempts.
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Given that the three characters are always asked for in order, analyze the array so as to determine the shortest possible secret passcode of unknown length.
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>passcodeDerivation(keylog)</code> should return a number.
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testString: assert(typeof passcodeDerivation(keylog) === 'number');
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- text: <code>passcodeDerivation(keylog)</code> should return 73162890.
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testString: assert.strictEqual(passcodeDerivation(keylog), 73162890);
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function passcodeDerivation(arr) {
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// Good luck!
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return true;
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}
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// Only change code above this line
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const keylog = [
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319,680,180,690,129,620,762,689,762,318,368,710,720,710,629,168,160,689,716,731,736,729,316,729,729,710,769,290,719,680,318,389,162,289,162,718,729,319,790,680,890,362,319,760,316,729,380,319,728,716,
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];
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passcodeDerivation(keylog);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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