「架构师训练营第 1 期」第十一周作业

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class CheckPassword {
    static String SALT = "this is a salt String";
    public static final String KEY_MD5 = "MD5";
    boolean checkPW(String username, String password, String passwordEncrypt) throws NoSuchAlgorithmException {
        String passwordAddSalt = getPasswordEncrypt(username, password);
        return passwordEncrypt.equals(passwordAddSalt);
    }
    private String getPasswordEncrypt(String username, String pwd) throws NoSuchAlgorithmException {
        //获取加密算法
        MessageDigest md = getEncryptMethod(username);
        //获取盐
        String salt = getSalt(username);
        md.update((pwd + salt).getBytes());
        BigInteger PasswordEncrypt = new BigInteger(md.digest());
        //返回密文
        return PasswordEncrypt.toString(16);
    }
    private String getSalt(String username) {
        return username + SALT;
    }
    private MessageDigest getEncryptMethod(String username) throws NoSuchAlgorithmException {
        return MessageDigest.getInstance(KEY_MD5);
    }
}