Calculate the entropy of a password.
const passEnt = require('passEnt');
const H = passEnt('pswd'); // 18.801758872564367
Created
March 18, 2021 20:35
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Password Entropy
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| const pools = [ | |
| { id: 'numbers', pattern: /[0-9]/, size: 10 }, | |
| { id: 'l_letters', pattern: /[a-z]/, size: 26 }, | |
| { id: 'u_letters', pattern: /[A-Z]/, size: 26 }, | |
| { id: 'symbols', pattern: /[^a-zA-Z0-9]/, size: 40 } | |
| ]; | |
| const getUsedPools = (password) => { | |
| const used = []; | |
| for(let index = 0; index < password.length; index++) { | |
| const char = password.charAt(index); | |
| const pool = pools.find(p => p.pattern.test(char)); | |
| if (pool && used.findIndex(p => p.id === pool.id) === -1) { | |
| used.push(pool); | |
| } | |
| } | |
| return used; | |
| }; | |
| const calcPoolSize = (pools) => { | |
| let size = 0; | |
| pools.forEach(pool => { | |
| size += pool.size; | |
| }); | |
| return size; | |
| }; | |
| const calcPoolEntropy = (pools) => { | |
| const size = calcPoolSize(pools); | |
| return Math.log2(size); | |
| }; | |
| module.exports = (password) => { | |
| const pools = getUsedPools(password); | |
| const charEntropy = calcPoolEntropy(pools); | |
| return password.length * charEntropy; | |
| }; |
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