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26 lines
1.1 KiB
26 lines
1.1 KiB
2 years ago
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# Semi Brute
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Hash functions are used to secure information. A piece of data, for instance a password, is hashed and only its hash is stored. While there is no way to compute on the original information, one can try every possible value. This is called a brute force attack.
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Proof of Work algorithms work in a similar manner. Miners hash a block and modify it continuously to obtain a certain value.
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We will create an example of this with a function that finds a string which hash starts with a given value.
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### Instructions
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Create a function `semiBrute()` that takes as argument a target, which is a two characters hexadecimal number, and returns a string which hash `sha256` starts with the target.
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### Usage
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```js
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solution = semiBrute("e2");
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console.log(solution);
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// One valid result : 'abcdefghijklmnopqrs'
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// You might find other valid solutions as we only check the first two characters
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```
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### Notions
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- [Module crypto: hash](https://nodejs.org/docs/latest-v14.x/api/crypto.html#crypto_class_hash)
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- [Password cracking (video)](https://www.youtube.com/watch?v=7U-RbOKanYs)
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