What causes the error “java.security.InvalidKeyExc

问题:

This question already has an answer here:

Why does my AES encryption throws an InvalidKeyException? (1 answer)

Closed 4 years ago.

I'm trying to encrypt and decrypt a string using AES but getting an error I don't know how to resolve. This is the code:

public class EncryptionTest{

public static void main(String[] args) {        
    String encrypt = new String(encrypt("1234567890123456"));
    System.out.println("decrypted value:" + (decrypt("ThisIsASecretKey",encrypt)));
}

public static String encrypt(String value) {
    try {
        byte[] raw = new byte[]{'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y'};
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] encrypted = cipher.doFinal(value.getBytes());
        System.out.println("encrypted string:" + (new String(encrypted)));
        return new String(skeySpec.getEncoded());
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return null;
}

public static String decrypt(String key, String encrypted) {
    try {
        SecretKeySpec skeySpec = new SecretKeySpec(Base64.decodeBase64(key), "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(skeySpec.getEncoded(),"AES"));
            (*)
        byte[] original = cipher.doFinal(Base64.decodeBase64(encrypted));
        original.toString();
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return null;
}  
}

When I run it the "decription" values is null. It fails before the (***) !!

It gives me an exception:

java.security.InvalidKeyException: Parameters missing
    at com.sun.crypto.provider.CipherCore.init(CipherCore.java:388)
    at com.sun.crypto.provider.AESCipher.engineInit(AESCipher.java:186)
    at javax.crypto.Cipher.implInit(Cipher.java:787)
    at javax.crypto.Cipher.chooseProvider(Cipher.java:849)
    at javax.crypto.Cipher.init(Cipher.java:1213)
    at javax.crypto.Cipher.init(Cipher.java:1153)
    at firma.XmlEncryptionTest.decrypt(EncryptionTest.java:63)
    at firma.XmlEncryptionTest.main(EncryptionTest.java:41)

where the line 63 is the one before (***). I don't know what am I doing wrong and how to solve. I looked around on the internet but without finding out what coul be that missing parameter

回答1:

The main issue in your code was caused by a failure to specify an IV value. You must specify an IV value when doing CBC-mode encryption and use that same value when performing the CBC-mode decryption.

Another problem is the mix and match of creating strings from byte arrays and base64-encoding. You also return null from your decrypt method every time. Even if you meant return original.toString();, that's still wrong (because toString() doesn't do what you wish it would on a byte array).

Below is an improved version of your code. It's far from optimal, but it compiles and works. You need to improve this to use a random IV. Also, if you plan to derive keys from passwords, don't just get the bytes, use a derivation function such as PBKDF2. You can see an example of using PBKDF2 in the JNCryptor source.

public class EncryptionTest {

  public static void main(String[] args) {
    try {

      String key = "ThisIsASecretKey";
      byte[] ciphertext = encrypt(key, "1234567890123456");
      System.out.println("decrypted value:" + (decrypt(key, ciphertext)));

    } catch (GeneralSecurityException e) {
      e.printStackTrace();
    }
  }

  public static byte[] encrypt(String key, String value)
      throws GeneralSecurityException {

    byte[] raw = key.getBytes(Charset.forName("UTF-8"));
    if (raw.length != 16) {
      throw new IllegalArgumentException("Invalid key size.");
    }

    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec,
        new IvParameterSpec(new byte[16]));
    return cipher.doFinal(value.getBytes(Charset.forName("UTF-8")));
  }

  public static String decrypt(String key, byte[] encrypted)
      throws GeneralSecurityException {

    byte[] raw = key.getBytes(Charset.forName("UTF-8"));
    if (raw.length != 16) {
      throw new IllegalArgumentException("Invalid key size.");
    }
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec,
        new IvParameterSpec(new byte[16]));
    byte[] original = cipher.doFinal(encrypted);

    return new String(original, Charset.forName("UTF-8"));
  }
}

回答2:

If you use a block-chaining mode like CBC, you need to provide an IvParameterSpec to the Cipher as well.

public class EncryptionTest {

static byte[] raw = new byte[]{'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y'};

static SecureRandom rnd = new SecureRandom();

static IvParameterSpec iv = new IvParameterSpec(rnd.generateSeed(16));

public static void main(String[] args) {
    String encrypt = encrypt("1234567890123456");
    System.out.println("decrypted value:" + (decrypt("ThisIsASecretKey", encrypt)));
}

public static String encrypt(String value) {
    try {

        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec,iv);
        byte[] encrypted = cipher.doFinal(value.getBytes());
        System.out.println("encrypted string:" + Base64.encodeBase64String(encrypted));
        return Base64.encodeBase64String(encrypted);
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return null;
}

public static String decrypt(String key, String encrypted) {
    try {
        SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes(), "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec,iv);
        byte[] original = cipher.doFinal(Base64.decodeBase64(encrypted));

        return new String(original);
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return null;
}

}

回答3:

Even though its too late but still I'm giving my solution for others.Please refer below working code to encrypt and decrypt data.

public static byte[] encrypt(String value) {
        byte[] encrypted = null;
        try {

            byte[] raw = new byte[]{'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y'};
            Key skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            byte[] iv = new byte[cipher.getBlockSize()];

            IvParameterSpec ivParams = new IvParameterSpec(iv);
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec,ivParams);
            encrypted  = cipher.doFinal(value.getBytes());
            System.out.println("encrypted string:" + encrypted.length);

        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return encrypted;
    }

    public static  byte[]  decrypt(byte[] encrypted) {
         byte[] original = null;
         Cipher cipher = null;
        try {
            byte[] raw = new byte[]{'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y'};
            Key key = new SecretKeySpec(raw, "AES");
            cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            //the block size (in bytes), or 0 if the underlying algorithm is not a block cipher
            byte[] ivByte = new byte[cipher.getBlockSize()];
            //This class specifies an initialization vector (IV). Examples which use
            //IVs are ciphers in feedback mode, e.g., DES in CBC mode and RSA ciphers with OAEP encoding operation.
            IvParameterSpec ivParamsSpec = new IvParameterSpec(ivByte);
            cipher.init(Cipher.DECRYPT_MODE, key, ivParamsSpec);
            original= cipher.doFinal(encrypted);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return original;
    }