PBKDF2的加密

蔚落 2021-09-16 06:56 235阅读 0赞

public class PasswordEncryption {
    	public static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA1";
    	 
    	/**
    	 * 盐的长度
    	 */
    	public static final int SALT_BYTE_SIZE = 32 / 2;
     
    	/**
    	 * 生成密文的长度
    	 */
    	public static final int HASH_BIT_SIZE = 128 * 4;
     
    	/**
    	 * 迭代次数
    	 */
    	public static final int PBKDF2_ITERATIONS = 1000;
     
    	/**
    	 * 对输入的密码进行验证
    	 * 
    	 * @param attemptedPassword
    	 *            待验证的密码
    	 * @param encryptedPassword
    	 *            密文
    	 * @param salt
    	 *            盐值
    	 * @return 是否验证成功
    	 * @throws NoSuchAlgorithmException
    	 * @throws InvalidKeySpecException
    	 */
    	public static boolean authenticate(String attemptedPassword, String encryptedPassword, String salt)
    			throws NoSuchAlgorithmException, InvalidKeySpecException {
    		// 用相同的盐值对用户输入的密码进行加密
    		String encryptedAttemptedPassword = getEncryptedPassword(attemptedPassword, 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 encryptedAttemptedPassword.equals(encryptedPassword);
    	}
     
    	/**
    	 * 生成密文
    	 * 
    	 * @param password
    	 *            明文密码
    	 * @param salt
    	 *            盐值
    	 * @return
    	 * @throws NoSuchAlgorithmException
    	 * @throws InvalidKeySpecException
    	 */
    	public static String getEncryptedPassword(String password, String salt) throws NoSuchAlgorithmException,
    			InvalidKeySpecException {
     
    		KeySpec spec = new PBEKeySpec(password.toCharArray(), fromHex(salt), PBKDF2_ITERATIONS, HASH_BIT_SIZE);
    		SecretKeyFactory f = SecretKeyFactory.getInstance(PBKDF2_ALGORITHM);
    		return toHex(f.generateSecret(spec).getEncoded());
    	}
     
    	/**
    	 * 通过提供加密的强随机数生成器 生成盐
    	 * 
    	 * @return
    	 * @throws NoSuchAlgorithmException
    	 */
    	public static String generateSalt() throws NoSuchAlgorithmException {
    		SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
    		byte[] salt = new byte[SALT_BYTE_SIZE];
    		random.nextBytes(salt);
     
    		return toHex(salt);
    	}
     
    	/**
    	 * 十六进制字符串转二进制字符串
    	 * 
    	 * @param   hex         the hex string
    	 * @return              the hex string decoded into a byte array      
    	 */
    	private static byte[] fromHex(String hex) {
    		byte[] binary = new byte[hex.length() / 2];
    		for (int i = 0; i < binary.length; i++) {
    			binary[i] = (byte) Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);
    		}
    		return binary;
    	}
     
    	/**
    	 * 二进制字符串转十六进制字符串
    	 * 
    	 * @param   array       the byte array to convert
    	 * @return              a length*2 character string encoding the byte array      
    	 */
    	private static String toHex(byte[] array) {
    		BigInteger bi = new BigInteger(1, array);
    		String hex = bi.toString(16);
    		int paddingLength = (array.length * 2) - hex.length();
    		if (paddingLength > 0)
    			return String.format("%0" + paddingLength + "d", 0) + hex;
    		else
    			return hex;
    	}
    	
    	public static void main(String[] args) {
    		String password = "666666";
    		String salt;
    		String ciphertext;
    		try {
     
    			salt = PasswordEncryption.generateSalt();
    			ciphertext = PasswordEncryption.getEncryptedPassword(password, salt);
    			boolean result = PasswordEncryption.authenticate(password, ciphertext, salt);
     
    			System.out.println(password + "  " + password.length());
    			System.out.println(salt + "  " + salt.length());
    			System.out.println(ciphertext + "  " + ciphertext.length());
    			if (result) {
    				System.out.println("succeed");
    			} else {
    				System.out.println("failed");
    			}
    		} catch (NoSuchAlgorithmException e) {
    			System.out.println("NoSuchAlgorithmException");
    		} catch (InvalidKeySpecException e) {
    			System.out.println("InvalidKeySpecException");
    		}
    	}
    
    }