public StreamCipherDecryptor() {
cryptogramsArray = Operations.getCryptogramsArray(cryptogramsFilePath);
codeToDecrypt = cryptogramsArray[cryptogramsArray.length - 1];
max = codeToDecrypt.size();
key = new int[codeToDecrypt.size()];
/** **************** Initialize every key value on -1 ********************* */
for (int i = 0; i < key.length; i++) key[i] = -1;
/** *********** Getting every chars that can be used in text ************** */
possibleChars = Operations.getPossibleChars();
/** *********** In loop program looking for most probably keys ************ */
for (int i = 0; i < max; i++) {
probablyKeys = new ArrayList<>();
for (ArrayList<Integer> cryptogram : cryptogramsArray) {
int value = cryptogram.get(i);
for (SingleChar singleChar : possibleChars) {
int key = xor(value, singleChar.getCharacter());
ProbablyKey p = getProbablyKey(key);
if (p == null) {
p = new ProbablyKey(key);
p.addWeight(singleChar.getWeight());
probablyKeys.add(p);
} else p.addWeight(singleChar.getWeight());
}
}
probablyKeys = Sort.sort(probablyKeys);
key[i] = chooseBestKey(i);
}
printDecryted();
}
private int chooseBestKey(int i) {
for (ProbablyKey p : probablyKeys) {
int counter = 0;
for (ArrayList<Integer> cryptogram : cryptogramsArray) {
int encrypted = xor(cryptogram.get(i), p.getKey());
if (!isCharacter(encrypted)) break;
counter++;
}
if (counter > cryptogramsArray.length - 1) return p.getKey();
}
return -1;
}
private ProbablyKey getProbablyKey(int key) {
for (ProbablyKey probablyKey : probablyKeys)
if (probablyKey.getKey() == key) return probablyKey;
return null;
}
