Initial data commit

Task/Parallel-brute-force/Java/parallel-brute-force-2.java

@@ -0,0 +1,82 @@
+import javax.xml.bind.DatatypeConverter;
+import java.security.*;
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.*;
+
+public class ParallelBruteForce {
+    public static void main(String[] args) {
+        try {
+            String[] hashes = {
+                "1115dd800feaacefdf481f1f9070374a2a81e27880f187396db67958b207cbad",
+                "3a7bd3e2360a3d29eea436fcfb7e44c735d117c42d1c1835420b6b9942dd4f1b",
+                "74e1bb62f8dabb8125a58852b63bdf6eaef667cb56ac7f7cdba6d7305c50a22f"};
+            ParallelBruteForce pbf = new ParallelBruteForce(5, hashes);
+            pbf.findPasswords();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    private ParallelBruteForce(int length, String[] hashes) {
+        this.length = length;
+        this.hashes = hashes;
+        digests = new byte[hashes.length][];
+        for (int i = 0; i < hashes.length; ++i)
+            digests[i] = DatatypeConverter.parseHexBinary(hashes[i]);
+    }
+
+    private void findPasswords() throws Exception {
+        count.set(length);
+        int processors = Runtime.getRuntime().availableProcessors();
+        ExecutorService svc = Executors.newFixedThreadPool(processors);
+        List<Future<?>> tasks = new ArrayList<>();
+        for (int i = 0; i < 26; ++i)
+            tasks.add(svc.submit(new PasswordFinder((byte)(97 + i))));
+        for (Future<?> task : tasks)
+            task.get();
+        svc.shutdown();
+    }
+
+    private static boolean nextPassword(byte[] passwd, int start) {
+        int len = passwd.length;
+        for (int i = len - 1; i >= start; --i) {
+            if (passwd[i] < 122) {
+                ++passwd[i];
+                return true;
+            }
+            passwd[i] = 97;
+        }
+        return false;
+    }
+
+    private class PasswordFinder implements Runnable {
+        private byte ch;
+        private MessageDigest md = MessageDigest.getInstance("SHA-256");
+        private PasswordFinder(byte c) throws NoSuchAlgorithmException {
+            ch = c;
+        }
+        public void run() {
+            byte[] passwd = new byte[length];
+            Arrays.fill(passwd, (byte)97);
+            passwd[0] = ch;
+            while (count.get() > 0) {
+                byte[] digest = md.digest(passwd);
+                for (int m = 0; m < hashes.length; ++m) {
+                    if (Arrays.equals(digest, digests[m])) {
+                        count.decrementAndGet();
+                        System.out.println("password: " + new String(passwd) + ", hash: " + hashes[m]);
+                        break;
+                    }
+                }
+                if (!nextPassword(passwd, 1))
+                    break;
+            }
+        }
+    }
+
+    private int length;
+    private String[] hashes;
+    private byte[][] digests;
+    private AtomicInteger count = new AtomicInteger();
+}