PBKDF2加密

PBKDF2算法通过多次hash来对密码进行加密。原理是通过password和salt进行hash，然后将结果作为salt在与password进行hash，多次重复此过程，生成最终的密文。

如何验证密码正确？

用相同的盐值对用户输入的密码进行加密，如果与密文比对，相同则密码正确。

// 迭代次数
public static final int PBKDF2_ITERATIONS = 1000;

public class PBKDF2
{
    public static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA1";

    //盐的长度
    public static final int SALT_SIZE = 16;

    //生成密文的长度
    public static final int HASH_SIZE = 32;

    // 迭代次数
    public static final int PBKDF2_ITERATIONS = 1000;

    /**
     * 对输入的密码进行验证
     *
     */
    public static boolean verify(String password, String salt, String key)
            throws NoSuchAlgorithmException, InvalidKeySpecException {
        // 用相同的盐值对用户输入的密码进行加密
        String result = getPBKDF2(password, salt);
        // 把加密后的密文和原密文进行比较，相同则验证成功，否则失败
        return result.equals(key);
    }

    /**
     * 根据password和salt生成密文
     *
     */
    public static String getPBKDF2(String password, String salt) throws NoSuchAlgorithmException,
            InvalidKeySpecException {
        //将16进制字符串形式的salt转换成byte数组
        byte[] bytes = DatatypeConverter.parseHexBinary(salt);
        KeySpec spec = new PBEKeySpec(password.toCharArray(), bytes, PBKDF2_ITERATIONS, HASH_SIZE * 4);
        SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance(PBKDF2_ALGORITHM);
        byte[] hash = secretKeyFactory.generateSecret(spec).getEncoded();
        //将byte数组转换为16进制的字符串
        return DatatypeConverter.printHexBinary(hash);
    }


    /**
     * 生成随机盐值
     *
     */
    public static String getSalt() throws NoSuchAlgorithmException {
        SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
        byte[] bytes = new byte[SALT_SIZE / 2];
        random.nextBytes(bytes);
        //将byte数组转换为16进制的字符串
        String salt = DatatypeConverter.printHexBinary(bytes);
        return salt;
    }

    public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeySpecException {
        String salt = getSalt();
        System.out.println(salt);
        String pdkdf2Password = getPBKDF2("haiying", salt);
        System.out.println(pdkdf2Password);
        //System.out.println(verify("admin","278663392F2E837C","02C3E6550F0AB1EAEB54E8351D633FB8"));
    }