Question

我有一个加密/解密算法，我试图加密一些特殊字符从android发送到服务器，但它抛出一个例外：

java.lang.Exception：[encrypt]错误：0607F08A：数字包络例程：EVP_EncryptFinal_ex：数据不是块长度的倍数

普通拉丁字符加密/解密正常，但特殊字符不是。

这是我的代码：

public class MCrypt {

    private String iv = "fedcba9876543210";//Dummy iv (CHANGE IT!)
    private IvParameterSpec ivspec;
    private SecretKeySpec keyspec;
    private Cipher cipher;

    private String SecretKey = "0123456789abcdef";//Dummy secretKey (CHANGE IT!)

    public MCrypt()
    {
        ivspec = new IvParameterSpec(iv.getBytes());
        keyspec = new SecretKeySpec(SecretKey.getBytes(), "AES");
        try {
            cipher = Cipher.getInstance("AES/CBC/NoPadding");
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public byte[] encrypt(String text) throws Exception
    {
        //if(text == null || text.length() == 0)
        //  throw new Exception("Empty string");

        byte[] encrypted = null;
        try {
            cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);

            encrypted = cipher.doFinal(padString(text).getBytes());
        } catch (Exception e)
        {                       
            throw new Exception("[encrypt] " + e.getMessage());
        }

        return encrypted;
    }

    public byte[] decrypt(String code) throws Exception
    {
        if(code == null || code.length() == 0)
            throw new Exception("Empty string");

        byte[] decrypted = null;

        try {
            cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

            decrypted = cipher.doFinal(hexToBytes(code));
        } catch (Exception e)
        {
            throw new Exception("[decrypt] " + e.getMessage());
        }
        return decrypted;
    }

    public static String bytesToHex(byte[] data)
    {
        if (data==null)
        {
            return null;
        }

        int len = data.length;
        String str = "";
        for (int i=0; i<len; i++) {
            if ((data[i]&0xFF)<16)
                str = str + "0" + Integer.toHexString(data[i]&0xFF);
            else
                str = str + Integer.toHexString(data[i]&0xFF);
            }
        return str;
    }

    public static byte[] hexToBytes(String str) {
        if (str==null) {
            return null;
        } else if (str.length() < 2) {
            return null;
        } else {
            int len = str.length() / 2;
            byte[] buffer = new byte[len];
            for (int i=0; i<len; i++) {
                buffer[i] = (byte) Integer.parseInt(str.substring(i*2,i*2+2),16);
            }
            return buffer;
        }
    }

    private static String padString(String source)
    {
        char paddingChar = ' ';
        int size = 32;
        int x = source.length() % size;
        int padLength = size - x;

        for (int i = 0; i < padLength; i++)
        {
            source += paddingChar;
        }

        return source;
    }
}

有谁知道这里的问题是什么？

谢谢！

Answer 1

更改此行：

cipher = Cipher.getInstance("AES/CBC/NoPadding");

要

cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

Answer 2

来自this Blog

更改此行：

cipher = Cipher.getInstance("AES/CBC/NoPadding"); //this may be not decrypt full plaintext.

要：

cipher = Cipher.getInstance("AES/ECB/PKCS7Padding"); // use this for descrypt full plain text without lost.

无法加密特殊字符：不是块长度的倍数

2 个答案: