android - 如何实现 AES 加密技术

Question

我想在java中为android应用程序实现AES技术，我为此搜索了很多教程，但这并不是超级好的。因此，如果有人知道代码，请在这方面提供帮助，以实现 ANDROID 应用程序的 AES 技术。提前谢谢。

Answer 1

aes ecrpt 类包 com.d.social.network；

import java.security.NoSuchAlgorithmException;

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

    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));
                if( decrypted.length > 0)
                {
                    int trim = 0;
                    for( int i = decrypted.length - 1; i >= 0; i-- ) if( decrypted[i] == 0 ) trim++;

                    if( trim > 0 )
                    {
                        byte[] newArray = new byte[decrypted.length - trim];
                        System.arraycopy(decrypted, 0, newArray, 0, decrypted.length - trim);
                        decrypted = newArray;
                    }
                }
            } 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" + java.lang.Integer.toHexString(data[i]&0xFF);
                else
                    str = str + java.lang.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 = 16;
          int x = source.length() % size;
          int padLength = size - x;

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

          return source;
        }
    }

使用它

MCrypt mcrypt = new MCrypt();
 MCrypt.bytesToHex( mcrypt.encrypt("hello"));