I'm trying to make it so that a string generates n keys, and all of those are required to recover the original string. For this, I generate n-1 random strings, XOR them all together with the original string to get the nth one. XORing these n strings reproduces the original strings
How secure is this? Is there any better method?
Also, is the code itself good enough? What can I do to improve it in terms of security/speed/readability/best practices?
package crypto;
import java.io.UnsupportedEncodingException;
import java.security.SecureRandom;
/**
* Created by hooda on 2/3/2015.
*/
public class XOR {
//Testing the functionality.
public static void main(String[] args) throws Exception {
XOR xor = new XOR();
String text = "Mr. and Mrs. Dursley, of number four Privet Drive, were proud to say that they were perfectly normal, thank you very much.";
String[] pieces = xor.encrypt(text, 5);
System.out.println(pieces[0]);
System.out.println(pieces[1]);
System.out.println(pieces[2]);
System.out.println(pieces[3]);
System.out.println(pieces[4]);
String test = xor.decrypt(pieces);
System.out.println(test);
}
public String[] encrypt(String s, int n) throws Exception {
int length = s.length();
String[] pieces = new String[n];
for (int i = 0; i < n - 1; i++) {
pieces[i] = keyGen(length);
}
String nth = s;
for (int i = 0; i < n - 1; i++) {
nth = doXOR(pieces[i], nth);
}
pieces[n - 1] = nth;
return pieces;
}
public String decrypt(String[] pieces) {
String decrypted = new String(new char[pieces[0].length()]).replace("\0", Character.toString((char) 0));
for (String piece : pieces) {
decrypted = doXOR(piece, decrypted);
}
return decrypted;
}
public String toBinary(String s) throws Exception {
byte[] bytes = s.getBytes("ASCII");
StringBuilder binary = new StringBuilder();
for (byte b : bytes) {
int val = b;
for (int i = 0; i < 8; i++) {
binary.append((val & 128) == 0 ? 0 : 1);
val <<= 1;
}
}
return binary.toString();
}
public String keyGen(int length) throws UnsupportedEncodingException {
SecureRandom srand = new SecureRandom();
byte[] bytes = new byte[length];
srand.nextBytes(bytes);
return new String(bytes, "ASCII");
}
public String doXOR(String s1, String s2) throws IllegalArgumentException {
String ret;
if (s1.length() != s2.length()) {
throw new IllegalArgumentException("The bit strings must have equal length!");
} else {
ret = "";
for (int i = 0; i < s1.length(); i++) {
char c1 = s1.charAt(i);
char c2 = s2.charAt(i);
int i1 = (int) c1;
int i2 = (int) c2;
int i3 = i1 ^ i2;
char c3 = (char) i3;
ret += c3;
}
}
return ret;
}
}
