获取异常java.security.InvalidKeyException:无效的AES密钥长度:29个字节？

Question

当在程序下面运行时,我得到了这个例外.无法弄清楚AES的问题是什么允许128 -256位密钥？

 Exception in thread "main" java.security.InvalidKeyException: Invalid AES key length: 29 bytes
at com.sun.crypto.provider.AESCipher.engineGetKeySize(DashoA13*..)
at javax.crypto.Cipher.b(DashoA13*..)

在第20行获得例外

这是程序

 import java.security.Key;

 import javax.crypto.Cipher;
 import javax.crypto.spec.SecretKeySpec;

 import sun.misc.BASE64Decoder;
 import sun.misc.BASE64Encoder;

 public class AESEncryptionDecryptionTest {

   private static final String ALGORITHM       = "AES";
   private static final String myEncryptionKey = "ThisIsSecurityKey";
   private static final String UNICODE_FORMAT  = "UTF8";

   public static String encrypt(String valueToEnc) throws Exception {
 Key key = generateKey();
 Cipher c = Cipher.getInstance(ALGORITHM);
 c.init(Cipher.ENCRYPT_MODE, key);  //////////LINE 20
 byte[] encValue = c.doFinal(valueToEnc.getBytes());
 String encryptedValue = new BASE64Encoder().encode(encValue);
 return encryptedValue;
   }

public static String decrypt(String encryptedValue) throws Exception {
Key key = generateKey();
Cipher c = Cipher.getInstance(ALGORITHM);
c.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = new BASE64Decoder().decodeBuffer(encryptedValue);
byte[] decValue = c.doFinal(decordedValue);
String decryptedValue = new String(decValue);
return decryptedValue;
}

private static Key generateKey() throws Exception {
byte[] keyAsBytes;
keyAsBytes = myEncryptionKey.getBytes(UNICODE_FORMAT);
Key key = new SecretKeySpec(keyAsBytes, ALGORITHM);
return key;
}

public static void main(String[] args) throws Exception {

String value = "password1";
String valueEnc = AESEncryptionDecryptionTest.encrypt(value);
String valueDec = AESEncryptionDecryptionTest.decrypt(valueEnc);

System.out.println("Plain Text : " + value);
System.out.println("Encrypted : " + valueEnc);
System.out.println("Decrypted : " + valueDec);
}

}

Answer 1

AES允许128,192或256位密钥长度.那是16,24或32字节.尝试只取你的前16个字节mEncryptionKey作为keyAsBytes.

编辑:
虽然发生在我之后.我已经形成的习惯,我推荐的习惯是获取密码/密码的SHA哈希,并将其用作密钥的源字节.无论密码/密码的长度如何,采用散列都可以保证密钥数据的大小正确.您当前使用String字节的实现有两个问题;

• 如果有人使用短密码,它将破坏密钥生成.
• 前16个字节相同的两个不同密码将创建相同的密钥.

通过使用散列消除了这两个问题.

看看buildKey()这堂课的方法; https://github.com/qwerky/DataVault/blob/master/src/qwerky/tools/datavault/DataVault.java