Question

任何人都可以告诉我为什么在解密任何字符串时我会获得额外的文字？这是我的代码

import android.support.v7.app.AppCompatActivity;    
import android.os.Bundle;    
import android.util.Log;    
import java.security.Security;    
import javax.crypto.Cipher;    
import javax.crypto.spec.SecretKeySpec;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Security.insertProviderAt(new org.spongycastle.jce.provider.BouncyCastleProvider(), 1);

        byte[] input = "this is a test taht we will use to text the validaty of your program, here goes nothing".getBytes();
        byte[] keyBytes = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04,
                0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c,
                0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14,
                0x15, 0x16, 0x17 };

        SecretKeySpec key = new SecretKeySpec(keyBytes, "AES");

        try
        {
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding", "SC");

            System.out.println(new String(input));

            // encryption pass
            cipher.init(Cipher.ENCRYPT_MODE, key);

            byte[] cipherText = new byte[cipher.getOutputSize(input.length)];
            int ctLength = cipher.update(input, 0, input.length, cipherText, 0);
            ctLength += cipher.doFinal(cipherText, ctLength);
            Log.i("testAppEncrypted --> ", new String(cipherText));
            System.out.println(ctLength);



            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] plainText = new byte[cipher.getOutputSize(ctLength)];
            int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0);
            ptLength += cipher.doFinal(plainText, ptLength);
            Log.i("testAppDecrypted --> ", new String(plainText));
            System.out.println(ptLength);
        }
        catch(Exception ex)
        {
            System.out.println(ex.getMessage());
        }

输出：

I / System.out：这是一个测试，我们将使用它来记录你的程序的有效性，这里什么都没有

I / testAppEncrypted - ＆gt;： BA ; 6D 'Wј ]！ f X P 6n~J W * j 6f P a p M ！ծ） @L + j d 8

I / System.out:96

我/ testAppDecrypted - ＆gt;：这是一个测试，我们将使用它来标记你的程序的有效性，这里什么也没做

I / System.out:87

为什么SpongyCastle解密在字符串末尾有垃圾

0 个答案: