Question

我需要使用带有32字节密钥的AES 256来加密XML消息（它以字符串形式出现）。我尝试了以下（来自http://aesencryption.net/）：

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
/**
Aes encryption
*/
public class AES
{

    private static SecretKeySpec secretKey ;
    private static byte[] key ;

    private static String decryptedString;
    private static String encryptedString;

    public static void setKey(String myKey){


        MessageDigest sha = null;
        try {
            key = myKey.getBytes("UTF-8");
            System.out.println(key.length);
            sha = MessageDigest.getInstance("SHA-1");
            key = sha.digest(key);
            key = Arrays.copyOf(key, 16); // use only first 128 bit
            System.out.println(key.length);
            System.out.println(new String(key,"UTF-8"));
            secretKey = new SecretKeySpec(key, "AES");


        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }



    }

    public static String getDecryptedString() {
        return decryptedString;
    }
    public static void setDecryptedString(String decryptedString) {
        AES.decryptedString = decryptedString;
    }
    public static String getEncryptedString() {
        return encryptedString;
    }
    public static void setEncryptedString(String encryptedString) {
        AES.encryptedString = encryptedString;
    }
    public static String encrypt(String strToEncrypt)
    {
        try
        {
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");

            cipher.init(Cipher.ENCRYPT_MODE, secretKey);


            setEncryptedString(Base64.encodeBase64String(cipher.doFinal(strToEncrypt.getBytes("UTF-8"))));

        }
        catch (Exception e)
        {

            System.out.println("Error while encrypting: "+e.toString());
        }
        return null;
    }
    public static String decrypt(String strToDecrypt)
    {
        try
        {
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");

            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            setDecryptedString(new String(cipher.doFinal(Base64.decodeBase64(strToDecrypt))));

        }
        catch (Exception e)
        {

            System.out.println("Error while decrypting: "+e.toString());
        }
        return null;
    }
    public static void main(String args[])
    {
                final String strToEncrypt = "My text to encrypt";
                final String strPssword = "C0BAE23DF8B51807B3E17D21925FADF273A70181E1D81B8EDE6C76A5C1F1716E";
                AES.setKey(strPssword);

                AES.encrypt(strToEncrypt.trim());

                System.out.println("String to Encrypt: " + strToEncrypt); 
                System.out.println("Encrypted: " + AES.getEncryptedString());

                final String strToDecrypt =  AES.getEncryptedString();
                AES.decrypt(strToDecrypt.trim());

                System.out.println("String To Decrypt : " + strToDecrypt);
                System.out.println("Decrypted : " + AES.getDecryptedString());

    }

    }

我尝试将键数组长度从16更改为32并使用更大的输入字符串
（我认为这是32个长度的关键），但这不起作用。

key = Arrays.copyOf(key, 32);

要加密的消息将如下所示：

<Estructure>
   <General>GENERAL DATA</General>
</Estructure>
<Datos>
   <DATE>20140606</DATE>
</Datos>

当我运行时，我得到以下例外：

加密时出错：java.security.InvalidKeyException：非法密钥大小或默认参数

使用16字节长度键时效果很好。如何使用32个字节？

Answer 1

默认情况下，JVM中禁用任何高于128位加密的内容，因为Oracle在美国的管辖范围内运行。

如果您想要超过128位加密，则必须下载Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files 8 Download并将jar文件放入JRE / JDK

AES 256 32字节密钥加密/解密Java

1 个答案: