import java.nio.charset.Charset;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.util.Base64;
import java.util.Random;import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;/*** pbkdf2_sha256加密验证算法* @author Administrator**/
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Pbkdf2Sha256 {private static final Logger logger=LoggerFactory.getLogger(Pbkdf2Sha256.class);//默认迭代计数为 20000private static final Integer DEFAULT_ITERATIONS = 20000;//算法名称private static final String algorithm = "pbkdf2_sha256";/*** 获取密文* @param password 密码明文* @param salt 加盐* @param iterations 迭代计数* @return*/private static String getEncodedHash(String password, String salt, int iterations) {// Returns only the last part of whole encoded passwordSecretKeyFactory keyFactory = null;try {keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");} catch (NoSuchAlgorithmException e) {logger.error("Could NOT retrieve PBKDF2WithHmacSHA256 algorithm",e);}KeySpec keySpec = new PBEKeySpec(password.toCharArray(), salt.getBytes(Charset.forName("UTF-8")), iterations, 256);SecretKey secret = null;try {secret = keyFactory.generateSecret(keySpec);} catch (InvalidKeySpecException e) {logger.error("Could NOT generate secret key",e);}byte[] rawHash = secret.getEncoded();byte[] hashBase64 = Base64.getEncoder().encode(rawHash);return new String(hashBase64);}/*** 密文加盐* @return String*/private static String getsalt(){int length = 12;Random rand = new Random();char[] rs = new char[length];for(int i = 0; i < length; i++){int t = rand.nextInt(3);if (t == 0) {rs[i] = (char)(rand.nextInt(10)+48);} else if (t == 1) {rs[i] = (char)(rand.nextInt(26)+65);} else {rs[i] = (char)(rand.nextInt(26)+97);}}return new String(rs);}/*** rand salt* iterations is default 20000* @param password* @return*/public static String encode(String password) {return encode(password, getsalt());}/*** rand salt* @param password* @return*/public static String encode(String password,int iterations) {return encode(password, getsalt(),iterations);}/*** iterations is default 20000* @param password* @param salt* @return*/public static String encode(String password, String salt) {return encode(password, salt, DEFAULT_ITERATIONS);}/*** * @param password 密码明文* @param salt 加盐* @param iterations 迭代计数* @return*/public static String encode(String password, String salt, int iterations) {// returns hashed password, along with algorithm, number of iterations and saltString hash = getEncodedHash(password, salt, iterations);return String.format("%s$%d$%s$%s", algorithm, iterations, salt, hash);}/*** 校验密码是否合法* @param password 明文* @param hashedPassword 密文* @return*/public static boolean verification(String password, String hashedPassword) {// hashedPassword consist of: ALGORITHM, ITERATIONS_NUMBER, SALT and// HASH; parts are joined with dollar character ("$")String[] parts = hashedPassword.split("\\$");if (parts.length != 4) {// wrong hash formatreturn false;}Integer iterations = Integer.parseInt(parts[1]);String salt = parts[2];String hash = encode(password, salt, iterations);return hash.equals(hashedPassword);}