java - ECC加密解密中的Base64编码/解码

Question

我想测试ECC算法加解密

我将代码写到:

• 生成 key 对(公钥和私钥)---> 将它们写入文件(可能不安全但我只是测试)。

• 然后使用公钥加密我的字符串(Java 编写)

• 现在，我获取加密后的字符串并尝试在 Android 上对其进行解密(使用私钥)

这是我的代码:

1. 用 Java 加密字符串:

   /// generate key pair
   ECNamedCurveParameterSpec spec = ECNamedCurveTable.getParameterSpec("prime256v1");
   try 
   {
       KeyPairGenerator g = KeyPairGenerator.getInstance("ECDSA",BouncyCastleProvider.PROVIDER_NAME);
       g.initialize(spec, new SecureRandom());
       KeyPair keyPair = g.generateKeyPair();
       privateKey = keyPair.getPrivate();
       publicKey = keyPair.getPublic();
       System.out.println("PublicKey:"+publicKey+"\n");
       System.out.println("PrivateKey:"+privateKey+"\n");
   
   } 
   catch (Exception e) 
   {
       e.printStackTrace();
   }
    try {
       Cipher c = Cipher.getInstance("ECIES",BouncyCastleProvider.PROVIDER_NAME);
       c.init(Cipher.ENCRYPT_MODE,publicKey);
       encodeBytes = c.doFinal(origin.getBytes());
       String encrypt = Base64.getEncoder().encodeToString(encodeBytes);
       System.out.println(encrypt);
   } catch (Exception e) {
       e.printStackTrace();
   }
   

我的输出加密字符串是这样的:

BB9Y4sKPbp28y7+FnpGnLGz5aTjD58GiIcXgjnNC4nXlUiqlHVVPc4K+ovlK5HK+Hz1Qps4ZWH9VdoYvm6VE36aEqvy53lJFnANDVpqAKuDUUaqEUrIQgF/TXFCFO22Il411atDsNhvJC3eRXbREL14duQbF8xjnLjru6WLN6GDYAQ==

这是我的私钥

-----BEGIN PRIVATE KEY-----
MIGTAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBHkwdwIBAQQgCybVICafKcZiEmGNw+Pj/FfL6GMgDc94/E0zJ/EKgdGgCgYIKoZIzj0DAQehRANCAATRTcV/M0OJE94qlZM7VksMOw35fcuGSxejdgzbyYllWtlIQw9gYhKPZx6t/PVOEOec4DyZq2XwaoNxBxWRboL1
-----END PRIVATE KEY-----

1. 在 Android 上解密字符串

   encodeBytes = Base64.decode(encrypted_string_above,Base64.DEFAULT);
   try
           {
               KeyFactory factory = KeyFactory.getInstance("ECDSA", "SC");
   
               String state;
               state = Environment.getExternalStorageState();
               File root = Environment.getExternalStorageDirectory();
               File dir = new File(root.getAbsolutePath()+"/disk");
               privateKeyFromFile = generatePrivateKey(factory,dir+"/private.pem");
   
               Cipher c = Cipher.getInstance("ECIES","SC");
               c.init(Cipher.DECRYPT_MODE,privateKeyFromFile);
               decodeBytes = c.doFinal(encodeBytes);
               String deCrypt = new String(decodeBytes,"UTF-8");
   
   
               txtHiden.setText(deCrypt);
               Toast.makeText(activity, deCrypt, Toast.LENGTH_SHORT).show();
           }
           catch (Exception ex)
           {
               ex.printStackTrace();
           }
   

但是我的代码没有成功解密，它有问题:

  10-03 00:52:18.264 28656-28656/com.example.napoleon.luanvana W/System.err: org.spongycastle.jcajce.provider.util.BadBlockException: unable to process block
  10-03 00:52:18.264 28656-28656/com.example.napoleon.luanvana W/System.err:     at org.spongycastle.jcajce.provider.asymmetric.ec.IESCipher.engineDoFinal(IESCipher.java:476)
  10-03 00:52:18.264 28656-28656/com.example.napoleon.luanvana W/System.err:     at javax.crypto.Cipher.doFinal(Cipher.java:2056)
  10-03 00:52:18.264 28656-28656/com.example.napoleon.luanvana W/System.err:     at com.example.napoleon.luanvana.MessageFragment$3.onClick(MessageFragment.java:156)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at android.view.View.performClick(View.java:6213)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at android.widget.TextView.performClick(TextView.java:11074)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at android.view.View$PerformClick.run(View.java:23645)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at android.os.Handler.handleCallback(Handler.java:751)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at android.os.Looper.loop(Looper.java:154)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:6692)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err: Caused by: org.spongycastle.crypto.InvalidCipherTextException: unable to recover ephemeral public key: Sender's public key has invalid point encoding 0x51
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at org.spongycastle.crypto.engines.IESEngine.processBlock(IESEngine.java:409)
  10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at org.spongycastle.jcajce.provider.asymmetric.ec.IESCipher.engineDoFinal(IESCipher.java:472)
 10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     ... 12 more
 10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err: Caused by: java.io.IOException: Sender's public key has invalid point encoding 0x51
 10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at org.spongycastle.crypto.parsers.ECIESPublicKeyParser.readKey(ECIESPublicKeyParser.java:46)
 10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     at org.spongycastle.crypto.engines.IESEngine.processBlock(IESEngine.java:405)
 10-03 00:52:18.265 28656-28656/com.example.napoleon.luanvana W/System.err:     ... 13 more

我认为这可能是由错误的编码/解码字符串 - 字节 - Base64 引起的

(Enctypt side)String encrypt = Base64.getEncoder().encodeToString(encodeBytes);
(Decrypt side): encodeBytes = Base64.decode(encrypted_string_above,Base64.DEFAULT);

但是我对这个问题没有多少经验。

Answer 1

在 ECIE 方案中，您应该使用 ECDH 作为生成加密/解密 key 对的算法，而不是 ECDSA，因为后者是一种数字签名算法。

KeyPairGenerator g = KeyPairGenerator.getInstance("ECDH",BouncyCastleProvider.PROVIDER)