add: import scrypt 1.4.0

[gigi.git] / lib / scrypt / com / lambdaworks / crypto / SCryptUtil.java

diff --git a/lib/scrypt/com/lambdaworks/crypto/SCryptUtil.java b/lib/scrypt/com/lambdaworks/crypto/SCryptUtil.java
new file mode 100644 (file)
index 0000000..ca29a00
--- /dev/null
+++ b/lib/scrypt/com/lambdaworks/crypto/SCryptUtil.java
@@ -0,0 +1,112 @@
+// Copyright (C) 2011 - Will Glozer.  All rights reserved.
+
+package com.lambdaworks.crypto;
+
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+import java.security.SecureRandom;
+
+import static com.lambdaworks.codec.Base64.*;
+
+/**
+ * Simple {@link SCrypt} interface for hashing passwords using the
+ * <a href="http://www.tarsnap.com/scrypt.html">scrypt</a> key derivation function
+ * and comparing a plain text password to a hashed one. The hashed output is an
+ * extended implementation of the Modular Crypt Format that also includes the scrypt
+ * algorithm parameters.
+ *
+ * Format: <code>$s0$PARAMS$SALT$KEY</code>.
+ *
+ * <dl>
+ * <dd>PARAMS</dd><dt>32-bit hex integer containing log2(N) (16 bits), r (8 bits), and p (8 bits)</dt>
+ * <dd>SALT</dd><dt>base64-encoded salt</dt>
+ * <dd>KEY</dd><dt>base64-encoded derived key</dt>
+ * </dl>
+ *
+ * <code>s0</code> identifies version 0 of the scrypt format, using a 128-bit salt and 256-bit derived key.
+ *
+ * @author  Will Glozer
+ */
+public class SCryptUtil {
+    /**
+     * Hash the supplied plaintext password and generate output in the format described
+     * in {@link SCryptUtil}.
+     *
+     * @param passwd    Password.
+     * @param N         CPU cost parameter.
+     * @param r         Memory cost parameter.
+     * @param p         Parallelization parameter.
+     *
+     * @return The hashed password.
+     */
+    public static String scrypt(String passwd, int N, int r, int p) {
+        try {
+            byte[] salt = new byte[16];
+            SecureRandom.getInstance("SHA1PRNG").nextBytes(salt);
+
+            byte[] derived = SCrypt.scrypt(passwd.getBytes("UTF-8"), salt, N, r, p, 32);
+
+            String params = Long.toString(log2(N) << 16L | r << 8 | p, 16);
+
+            StringBuilder sb = new StringBuilder((salt.length + derived.length) * 2);
+            sb.append("$s0$").append(params).append('$');
+            sb.append(encode(salt)).append('$');
+            sb.append(encode(derived));
+
+            return sb.toString();
+        } catch (UnsupportedEncodingException e) {
+            throw new IllegalStateException("JVM doesn't support UTF-8?");
+        } catch (GeneralSecurityException e) {
+            throw new IllegalStateException("JVM doesn't support SHA1PRNG or HMAC_SHA256?");
+        }
+    }
+
+    /**
+     * Compare the supplied plaintext password to a hashed password.
+     *
+     * @param   passwd  Plaintext password.
+     * @param   hashed  scrypt hashed password.
+     *
+     * @return true if passwd matches hashed value.
+     */
+    public static boolean check(String passwd, String hashed) {
+        try {
+            String[] parts = hashed.split("\\$");
+
+            if (parts.length != 5 || !parts[1].equals("s0")) {
+                throw new IllegalArgumentException("Invalid hashed value");
+            }
+
+            long params = Long.parseLong(parts[2], 16);
+            byte[] salt = decode(parts[3].toCharArray());
+            byte[] derived0 = decode(parts[4].toCharArray());
+
+            int N = (int) Math.pow(2, params >> 16 & 0xffff);
+            int r = (int) params >> 8 & 0xff;
+            int p = (int) params      & 0xff;
+
+            byte[] derived1 = SCrypt.scrypt(passwd.getBytes("UTF-8"), salt, N, r, p, 32);
+
+            if (derived0.length != derived1.length) return false;
+
+            int result = 0;
+            for (int i = 0; i < derived0.length; i++) {
+                result |= derived0[i] ^ derived1[i];
+            }
+            return result == 0;
+        } catch (UnsupportedEncodingException e) {
+            throw new IllegalStateException("JVM doesn't support UTF-8?");
+        } catch (GeneralSecurityException e) {
+            throw new IllegalStateException("JVM doesn't support SHA1PRNG or HMAC_SHA256?");
+        }
+    }
+
+    private static int log2(int n) {
+        int log = 0;
+        if ((n & 0xffff0000 ) != 0) { n >>>= 16; log = 16; }
+        if (n >= 256) { n >>>= 8; log += 8; }
+        if (n >= 16 ) { n >>>= 4; log += 4; }
+        if (n >= 4  ) { n >>>= 2; log += 2; }
+        return log + (n >>> 1);
+    }
+}