0

你好我正在制作一个加密和解密短信的安卓应用程序。我有一个问题，当短信的大小超过 80 个字符时，无法发送短信和应用程序。停止工作（给出错误）（少于 80 个字符没有错误，我可以发送 SMS）。我首先将消息转换为 byte( UTF-8)，然后使用getBytes().

这是 logcat 中的错误：

06-05 12:16:42.460: E/AndroidRuntime(333): java.lang.NullPointerException
06-05 12:16:42.460: E/AndroidRuntime(333):android.os.Parcel.readException(Parcel.java:1328)
06-05 12:16:42.460: E/AndroidRuntime(333):android.os.Parcel.readException(Parcel.java:1276)
06-05 12:16:42.460: E/AndroidRuntime(333):atcom.android.internal.telephony.ISms$Stub$Proxy.sendText(ISms.java:369)
06-05 12:16:42.460: E/AndroidRuntime(333):atandroid.telephony.SmsManager.sendTextMessage(SmsManager.java:87)
06-05 12:16:42.460: E/AndroidRuntime(333):atcom.cryptosms.MainActivity.sendSMS(MainActivity.java:296)
06-05 12:16:42.460: E/AndroidRuntime(333):atcom.cryptosms.MainActivity$3.onClick(MainActivity.java:142)
06-05 12:16:42.460: E/AndroidRuntime(333):at android.view.View.performClick(View.java:2485)
06-05 12:16:42.460: E/AndroidRuntime(333):atandroid.view.View$PerformClick.run(View.java:9080)
06-05 12:16:42.460: E/AndroidRuntime(333): atandroid.os.Handler.handleCallback(Handler.java:587)
06-05 12:16:42.460: E/AndroidRuntime(333): atandroid.os.Handler.dispatchMessage(Handler.java:92)
06-05 12:16:42.460: E/AndroidRuntime(333): at android.os.Looper.loop(Looper.java:123)
06-05 12:16:42.460: E/AndroidRuntime(333): atandroid.app.ActivityThread.main(ActivityThread.java:3683)
06-05 12:16:42.460: E/AndroidRuntime(333): at java.lang.reflect.Method.invokeNative(Native Method)
06-05 12:16:42.460: E/AndroidRuntime(333):atjava.lang.reflect.Method.invoke(Method.java:507)
06-05 12:16:42.460: E/AndroidRuntime(333):atcom.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
06-05 12:16:42.460: E/AndroidRuntime(333):atcom.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
06-05 12:16:42.460: E/AndroidRuntime(333): at dalvik.system.NativeStart.main(Native Method)
4

1 回答 1

0

您好尝试使用以下代码进行加密和解密。

import java.security.SecureRandom;

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

/**
 * Usage:
 * <pre>
 * String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)
 * ...
 * String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)
 * </pre>
 * @author ferenc.hechler
 */
public class SimpleCrypto {


    public static void main(String args[])
    {


        try {

            String sr=encrypt("username", "The AsyncTask isn’t the only way to do background processing in Android, though. The Loader class is a much newer construct in Android (although now it’s getting a bit dated). It was released with Honeycomb(3.0) and is now included in the Support Library. The beauty of the Loader is that it handles some of the ‘gotchas’ that usually are missed when using the AsyncTask. Mainly, it handles activity configuration changes (IE when the user rotates the screen)");
            System.out.println(" &&&& " + sr);
            System.out.println("88888 "+decrypt("username", sr));


        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
        public static String encrypt(String seed, String cleartext) throws Exception {
                byte[] rawKey = getRawKey(seed.getBytes());
                byte[] result = encrypt(rawKey, cleartext.getBytes());
                return toHex(result);
        }

        public static String decrypt(String seed, String encrypted) throws Exception {
                byte[] rawKey = getRawKey(seed.getBytes());
                byte[] enc = toByte(encrypted);
                byte[] result = decrypt(rawKey, enc);
                return new String(result);
        }

        private static byte[] getRawKey(byte[] seed) throws Exception {
                KeyGenerator kgen = KeyGenerator.getInstance("AES");
                SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
                sr.setSeed(seed);
            kgen.init(128, sr); // 192 and 256 bits may not be available
            SecretKey skey = kgen.generateKey();
            byte[] raw = skey.getEncoded();
            return raw;
        }


        private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
                Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
            byte[] encrypted = cipher.doFinal(clear);
                return encrypted;
        }

        private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
                Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            byte[] decrypted = cipher.doFinal(encrypted);
                return decrypted;
        }

        public static String toHex(String txt) {
                return toHex(txt.getBytes());
        }
        public static String fromHex(String hex) {
                return new String(toByte(hex));
        }

        public static byte[] toByte(String hexString) {
                int len = hexString.length()/2;
                byte[] result = new byte[len];
                for (int i = 0; i < len; i++)
                        result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
                return result;
        }

        public static String toHex(byte[] buf) {
                if (buf == null)
                        return "";
                StringBuffer result = new StringBuffer(2*buf.length);
                for (int i = 0; i < buf.length; i++) {
                        appendHex(result, buf[i]);
                }
                return result.toString();
        }
        private final static String HEX = "0123456789ABCDEF";
        private static void appendHex(StringBuffer sb, byte b) {
                sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
        }

}
于 2013-06-05T12:35:41.437 回答