加密后字節數組和字符串相互轉換

加密結果直接轉字符串

public class Client {
// 加密算法
  private static final String BLOWFISH = "Blowfish";
// 加密秘鑰
  private static final String SECRET = "test";

  public static void main(String[] args) throws Exception {
    String source = "hello";
    byte[] encrypt = encrypt(source);
    byte[] decrypt = decrypt(new String(encrypt));
    System.out.println(new String(decrypt));
  }

// 加密
  private static byte[] encrypt(String data) throws Exception {
    Cipher cipher = Cipher.getInstance(BLOWFISH);
    SecretKeySpec myskeys = new SecretKeySpec(SECRET.getBytes(), BLOWFISH);
    cipher.init(Cipher.ENCRYPT_MODE, myskeys);
    return cipher.doFinal(data.getBytes());
  }
// 解密
  private static byte[] decrypt(String data) throws Exception {
    Cipher cipher = Cipher.getInstance(BLOWFISH);
    SecretKeySpec myskeys = new SecretKeySpec(SECRET.getBytes(), BLOWFISH);
    cipher.init(Cipher.DECRYPT_MODE, myskeys);
    return cipher.doFinal(data.getBytes());
  }
}

運行結果為

Exception in thread "main" javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher
	at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:936)
	at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:847)
	at com.sun.crypto.provider.BlowfishCipher.engineDoFinal(BlowfishCipher.java:319)
	at javax.crypto.Cipher.doFinal(Cipher.java:2164)
	at com.imooc.sourcecode.java.base.java8.base64.test2.Client.decrypt(Client.java:28)
	at com.imooc.sourcecode.java.base.java8.base64.test2.Client.main(Client.java:13)

這是因為解密之后得到的字節數組是不符合UTF8，GBK等編碼規則的，轉成字符串再轉成字節數組，數據已經改變了，所以解密會出錯。

將加密結果轉為Base64再轉為字符串

public class Client {
  private static final String BLOWFISH = "Blowfish";
  private static final String SECRET = "test";

  public static void main(String[] args) throws Exception {
    String source = "hello";
    byte[] encrypt = encrypt(source);
    String encodeToString = Base64.getEncoder().encodeToString(encrypt);
    byte[] decode = Base64.getDecoder().decode(encodeToString);
    byte[] decrypt = decrypt(decode);
    System.out.println(new String(decrypt));
  }

  private static byte[] encrypt(String data) throws Exception {
    Cipher cipher = Cipher.getInstance(BLOWFISH);
    SecretKeySpec myskeys = new SecretKeySpec(SECRET.getBytes(), BLOWFISH);
    cipher.init(Cipher.ENCRYPT_MODE, myskeys);
    return cipher.doFinal(data.getBytes());
  }

  private static byte[] decrypt(byte[] data) throws Exception {
    Cipher cipher = Cipher.getInstance(BLOWFISH);
    SecretKeySpec myskeys = new SecretKeySpec(SECRET.getBytes(), BLOWFISH);
    cipher.init(Cipher.DECRYPT_MODE, myskeys);
    return cipher.doFinal(data);
  }
}

結果為hello，符合預期。