为什么我无法在Java环境中解码来自安卓设备的字符串？

huangapple
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英文:

Why i can not decode the string coming from Android devices with Java environment?

问题

我使用 Android 设备使用以下代码对字符串进行加密：

在 Android 端，密钥长度：2048

  1. //初始化：需要一些时间
  2. private void prepareEncrypt(String publicKey) throws Exception {
  3.     X509EncodedKeySpec keySpec = new X509EncodedKeySpec(Base64.getDecoder().decode(publicKey.getBytes()));
  4.     KeyFactory keyFactory = KeyFactory.getInstance("RSA");
  5.     PublicKey pubKey = keyFactory.generatePublic(keySpec);
  6.     cp = Cipher.getInstance("RSA/ECB/OAEPWithSHA-512AndMGF1Padding");
  7.     cp.init(Cipher.ENCRYPT_MODE, pubKey);
  8. }
  10. //加密
  11. private byte[] encryptByPublicKey(byte[] data) {
  12.     byte[] result = new byte[0];
  13.     try {
  14.         result = cp.doFinal(data);
  15.     } catch (BadPaddingException e) {
  16.         e.printStackTrace();
  17.     } catch (IllegalBlockSizeException e) {
  18.         e.printStackTrace();
  19.     }
  21.     return result;
  22. }

得到密文 A。

然后，我尝试在 Eclipse 上使用 Java 解码 A：

  1. public static byte[] decryptByPrivateKey(byte[] encrypted, byte[] privateKey) throws Exception {
  2.     PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.getDecoder().decode(privateKey));
  3.     KeyFactory kf = KeyFactory.getInstance("RSA");
  4.     PrivateKey keyPrivate = kf.generatePrivate(keySpec);
  5.     Cipher cp = Cipher.getInstance("RSA/ECB/OAEPWithSHA-512AndMGF1Padding");
  6.     cp.init(Cipher.DECRYPT_MODE, keyPrivate);
  7.     byte[] arr = cp.doFinal(Base64.getDecoder().decode(encrypted));
  8.     return arr;
  9. }

我总是无法成功解码字符串。

  1. javax.crypto.BadPaddingException: Decryption error
  2.     at sun.security.rsa.RSAPadding.unpadOAEP(Unknown Source)
  3.     at sun.security.rsa.RSAPadding.unpad(Unknown Source)
  4.     at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
  5.     at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)

如果 Android 端不更改 Cipher 对象上的 TRANSFORMATION 参数，例如：

RSA/ECB/NoPadding

RSA/ECB/PKCS1Padding

RSA/ECB/OAEPWithSHA-1AndMGF1Padding

RSA/ECB/OAEPWithSHA-224AndMGF1Padding

RSA/ECB/OAEPWithSHA-256AndMGF1Padding

RSA/ECB/OAEPWithSHA-384AndMGF1Padding

RSA/ECB/OAEPWithSHA-512AndMGF1Padding

如何成功解码密文 A？

英文:

I use Android deivces to encript a string with these code:

Android side , key length : 2048

  1. //Init: need time
  2. private void prepareEncrypt(String publicKey) throws Exception {
  3.     X509EncodedKeySpec keySpec = new X509EncodedKeySpec(Base64.getDecoder().decode(publicKey.getBytes()));
  4.     KeyFactory keyFactory = KeyFactory.getInstance("RSA");
  5.     PublicKey pubKey = keyFactory.generatePublic(keySpec);
  6.     cp = Cipher.getInstance("RSA/ECB/OAEPWithSHA-512AndMGF1Padding");
  7.     cp.init(Cipher.ENCRYPT_MODE, pubKey);
  8. }
  10. //encrypt
  11. private byte[] encryptByPublicKey(byte[] data) {
  12.     //data = Base64.getEncoder().encode(data);
  13.     byte[] result = new byte[0];
  14.     try {
  15.         result = cp.doFinal(data);
  16.     } catch (BadPaddingException e) {
  17.         e.printStackTrace();
  18.     } catch (IllegalBlockSizeException e) {
  19.         e.printStackTrace();
  20.     }
  22.     return result;
  23. }

Get a Ciphertext A.

Then i tried to decode the A with Java on elipse:

  1. public static byte[] decryptByPrivateKey(byte[] encrypted, byte[] privateKey) throws Exception {
  2.     PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.getDecoder().decode(privateKey));
  3.     KeyFactory kf = KeyFactory.getInstance("RSA");
  4.     PrivateKey keyPrivate = kf.generatePrivate(keySpec);
  5.     Cipher cp = Cipher.getInstance("RSA/ECB/OAEPWithSHA-512AndMGF1Padding");
  6.     cp.init(Cipher.DECRYPT_MODE, keyPrivate);
  7.     byte[] arr = cp.doFinal(Base64.getDecoder().decode(encrypted));
  8.     return arr;
  9. }

I always failed to decode the String.

  1. javax.crypto.BadPaddingException: Decryption error
  2.     at sun.security.rsa.RSAPadding.unpadOAEP(Unknown Source)
  3.     at sun.security.rsa.RSAPadding.unpad(Unknown Source)
  4.     at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
  5.     at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)

If the Android do not change the TRANSFORMATION paremeter on object Cipher Like:

RSA/ECB/NoPadding

RSA/ECB/PKCS1Padding

RSA/ECB/OAEPWithSHA-1AndMGF1Padding

RSA/ECB/OAEPWithSHA-224AndMGF1Padding

RSA/ECB/OAEPWithSHA-256AndMGF1Padding

RSA/ECB/OAEPWithSHA-384AndMGF1Padding

RSA/ECB/OAEPWithSHA-512AndMGF1Padding

How to decode the Ciphertext A successfully?

答案1

得分: 1

OAEPParameterSpec oaepParameterSpecDec = new OAEPParameterSpec("SHA-512", "MGF1", new MGF1ParameterSpec("SHA-512"), PSource.PSpecified.DEFAULT);
...
cp.init(Cipher.DECRYPT_MODE, keyPrivate, oaepParameterSpecDec);

显然提供了填充参数。

英文:

Need this :

  1.     OAEPParameterSpec oaepParameterSpecDec = new OAEPParameterSpec("SHA-512", "MGF1", new MGF1ParameterSpec("SHA-512"), PSource.PSpecified.DEFAULT);
  2.     ...
  3.     cp.init(Cipher.DECRYPT_MODE, keyPrivate, oaepParameterSpecDec);

obviously give the padding paremeters

huangapple
  • 本文由 发表于 2020年9月4日 11:46:03
  • 转载请务必保留本文链接：https://go.coder-hub.com/63734564.html
  • android
  • java
  • rsa
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