RSAGuess.java

import java.math.BigInteger;

import java.util.Date;

import java.util.HashMap;



/*

*

* This tool encrypts numbers with a given public key and replace similarities in the cipher text with the clear text.

* This tool only cracks the unmodified RSA algorithm with clear text sizes up to 2147483647 per number.

* It's only made for scientific purposes, not for criminal ones.

*

* @author mitosis

* @version 1.0

*

*/



public class RSAGuess {



public static void main(String[] args) {

try {

String argsadded = "";

for (int i = 0; i < args.length; i++) {

argsadded = argsadded + args[i];

}



if (argsadded.isEmpty() || argsadded.equalsIgnoreCase("version")) {

System.out.println("RSAGuess v1.0 by mitosis <[email protected]>."

+ "\nUse argument 'help' to learn how to use this tool.");

} else if (argsadded.equalsIgnoreCase("help")) {



System.out.println("The one and only rule: Use this tool ONLY for GOOD purposes."

+ "\nType the arguments like this: N e s l c d" + "\nN - RSA modulus" + "\ne - public exponent"

+ "\ns - smallest number exptected in message (the number doesn't has to exist in message!)"

+ "\nl - largest number expected in message (the number doesn't has to exist in message!)"

+ "\nc - ciphertext" + "\nd - delimiter" + "\n" + "\nA tip:"

+ "\nMaybe you are a kind of confused what s and l argument mean. Just use 0 for s and the highest number you expect in the message for l."

+ "\nAnother tip:"

+ "\nSome delimiter chars won't work. I never had problems with using a minus -");



} else {



BigInteger N = new BigInteger(args[0]);

BigInteger e = new BigInteger(args[1]);



String m = "";



int begin = Integer.parseInt(args[2]);



int end = Integer.parseInt(args[3]);



String chr = args[5];



String c = args[4];



int g = begin;



long start = new Date().getTime();



Dictionary d = new Dictionary();



HashMap<Integer, BigInteger> cMap = new HashMap<Integer, BigInteger>();



while (g <= end) {



BigInteger cipher = new BigInteger(Integer.toString(g)).modPow(e, N);



d.addEntry(g, cipher);



g++;

}



for (int i = 0; i < c.split(chr).length; i++) {

cMap.put(i, new BigInteger((c.split(chr)[i])));

}



g = 0;

String dSize = Integer.toString(d.getDictionary().size());



for (int i = 0; i < cMap.size(); i++) {

for (BigInteger b = new BigInteger("0"); b.compareTo(new BigInteger(dSize)) == -1; b = b

.add(new BigInteger("1"))) {



if (cMap.get(i).toString().equals(d.getDictionary().get(b.intValueExact()).toString())) {



cMap.put(i, b);



break;



}

}

}



for (int i = 0; i < cMap.size(); i++) {

if (i == cMap.size() - 1) {

m = m + cMap.get(i).toString();

} else {

m = m + cMap.get(i).toString() + chr;

}

}



long runningTime = new Date().getTime() - start;

BigInteger bits = new BigInteger(Integer.toString(N.toString(2).length() / 2));



System.out.println("cracked RSA-" + bits + " in " + runningTime + "ms. m=" + m);



}



} catch (Throwable e) {

System.out.println("Something went wrong. Use argument 'help'.");

}

}

}