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Update keyFinder.js

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Finally, there are several changes in the function keyFinder(str) that make it works well
This commit is contained in:
Wan Cheuk Lun
2018-10-31 16:54:20 +08:00
committed by GitHub
parent fed5d517fd
commit 75d7ef53dc
1 changed files with 31 additions and 15 deletions
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46
Ciphers/keyFinder.js
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@ -3,24 +3,40 @@ Find and retrieve the encryption key automatically
Note: This is a draft version, please help to modify, Thanks!
******************************************************/
function keyFinder(str){ // str is used to get the input of encrypted string
const wordbank =["is","Is","am","Am","are","Are","have","Have","has","Has","may","May","be","Be"];
let key = 0; // return zero means the key can not be found
const wordbank =[" the ","The "," of "," is ","Is "," am ","Am "," are ","Are "," have ","Have "," has ","Has "," may ","May "," be ","Be "];
//let wordbankelementCounter = 0;
//let key = 0; // return zero means the key can not be found
let inStr = str.toString(); //convert the input to String
let outStr = ""; // store the output value
let wordInOutStr = ""; // temporary store the word inside the outStr, it is used for comparison
for (let i=0; i<(52); i++){ //try the number of key shifted, the sum of character from a-z and A-Z is 26*2=52
outStr = caesarCipherEncodeAndDecodeEngine(inStr,i); // use the encrytpion engine to decrypt the input string, shiftNum=i
for ( let i=0; i<wordbank.length; i++){
// use a loop to find the next digit of wordbank element and compare with outStr's digit
for ( let j=0; j < wordbank[i].length; j++){
wordInOutStr += outStr[i+j];
}
// this part need to be optimize with the calculation of the number of occurance of word's probabilities
// linked list will be used in the next stage of development to calculate the number of occurace of the key
if (wordbank[i] == wordInOutStr){
return key=i; // return the key number if founded
}
let outStrElement = ""; // temporary store the word inside the outStr, it is used for comparison
for (let k=0; k<26; k++){ //try the number of key shifted, the sum of character from a-z or A-Z is 26
outStr = caesarCipherEncodeAndDecodeEngine(inStr,k); // use the encrytpion engine to decrypt the input string
//loop through the whole input string
for ( let s=0; s < outStr.length; s++){
for ( let i=0; i < wordbank.length; i++){
// initialize the outStrElement which is a temp output string for comparison,
// use a loop to find the next digit of wordbank element and compare with outStr's digit
for ( let w=0; w < wordbank[i].length; w++){
outStrElement += outStr[ s + w ];
}
//console.log( k + outStrElement + wordbank[i] );//debug
// this part need to be optimize with the calculation of the number of occurance of word's probabilities
// linked list will be used in the next stage of development to calculate the number of occurace of the key
if (wordbank[i] == outStrElement){
return k; // return the key number if founded
}
outStrElement = ""; //reset the temp word
} // end for ( let i=0; i < wordbank.length; i++)
}
}
return 0; // return 0 if found nothing
}