RegressionCipher/js/decrypt.js at master · CrypTools/RegressionCipher

21 lines (16 loc) · 657 Bytes

/***************************

Use: "Wy0xLjc4MjM2NDU0OTY3NTIyNjNlLTM0LC0 ... YyNzg2LDk3LjAwMDAwMDAwMDAwMDExXQ==".regdecrypt(6) // String is much longer in fact

=> "attack"

**************************/

const t = require("theorem.js") // We use TheoremJS (https://theorem.js.org) for all the math

const b64 = require('@cryptoolsorg/base64');

String.prototype.regdecrypt = function(length) {

let v = b64.decrypt(this)

let f = t.polynomial(...JSON.parse(v))

let arr = []

for (let i = 0; i < length; i++) {

arr.push(Math.round(f.core(i)))

}

return String.fromCharCode(...arr)

}

module.exports = (text, l) => text.regdecrypt(l)

Provide feedback