Java中的RSA BadPaddingException - 在Android中的加密解密JRE

Question

我發現了一些其他問題，但我沒有找到解釋是什麼原因造成的。我用Java編寫了一個函數來加密數據，將其存儲到一個文件中，並解密它再次加載文件。由於這是一個非對稱加密，我有一個公鑰和一個私鑰，直接存儲在代碼中用於測試目的。

這個問題似乎是加密本身的差異，因爲該功能在android以及安裝了java RE 7的Windows機器上工作。但是在JRE7系統上使用相同的密鑰和功能加密來自Android的數據是不可能的，結果是「bad padding exeption」。

對於測試目的，我只使用一個數據塊。由於en/decrypt在每個系統中都有效，所以我相信問題不是關鍵。最終版本將編碼和解碼二進制數據 - 所以我只是使用字節，不必擔心字符串中的不同字符集。在瞭解了原因之後，我將使用pureRSA解碼PHP中的數據。

import java.io.DataInputStream; 
import java.io.FileInputStream; 
import java.io.DataOutputStream; 
import java.io.FileOutputStream; 
import android.util.Base64; 
import java.math.BigInteger; 
import java.security.InvalidAlgorithmParameterException; 
import javax.crypto.Cipher; 
import java.security.KeyFactory; 
import java.security.spec.RSAPublicKeySpec; 
import java.security.spec.PKCS8EncodedKeySpec; 
import java.security.interfaces.RSAPrivateKey; 
import java.security.interfaces.RSAPublicKey; 
import java.security.NoSuchAlgorithmException; 
import java.security.NoSuchProviderException; 
import java.security.spec.InvalidKeySpecException; 
import javax.crypto.NoSuchPaddingException; 
import java.security.InvalidKeyException; 
import javax.crypto.IllegalBlockSizeException; 
import javax.crypto.BadPaddingException; 
import javax.crypto.ShortBufferException; 
import java.io.FileNotFoundException; 
import java.io.UnsupportedEncodingException; 
import java.io.IOException; 

public class test 
{ 
    public static void main (String args[]) throws FileNotFoundException, FileNotFoundException, 
      UnsupportedEncodingException, IOException, NoSuchAlgorithmException, InvalidKeySpecException, 
      NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, 
      ShortBufferException, NoSuchProviderException, InvalidAlgorithmParameterException { 

     Cipher CheckCipher = Cipher.getInstance("RSA"); 
     KeyFactory fact = KeyFactory.getInstance("RSA"); 
// one Block has 320 Bytes encrypted data or up to 309 Bytes decrypted data 
     byte[] encryptedBuffer = new byte[320]; 
// public key 
     RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger("348349717397217997016459044429876445798461822630613593827475516398929980499253048018915109820386668925158598090923917424889721436728681941788735398708226655486687058044818981687475046995966049152458371358433593409946449307673641432434645409125209056679079565878576322466469782078766479519331465759437687570449909733209874455595086928288016285095448723528960074392901021635076277130066403766286870175583368291319265676733584876043054873738027872260931903992491855282040202055048433338277681906526276056353076551640420301024861314931536846223479281788109044598118149113100016473709709779349227018363507068247312704031804719673776595496482605126340630418742698424978233098157782472641000027452801691972881854034867234891280067908910242015420737297077922221753325197819914227"), new BigInteger("65537")); 
     RSAPublicKey publicKey = (RSAPublicKey) fact.generatePublic(pubKeySpec); 
// private key 
     byte[] encoded = Base64.decode("MIIF3gIBADANBgkqhkiG9w0BAQEFAASCBcgwggXEAgEAAoIBQQDNz13heSUvu7J4d+d1VJBkx6D31ZBcaF3AAA0AFYPPkkPfGF9FneTITk/ft7n1PCT9MzBRzCIFyPEkk93I4tLdP4POUDCRGC1uDBOKBkjo8hMYROt+DtK6vAafhvs/sVJVcMAxYEOZl9wG/SS9KEFU9NktM2pBfq5x747AfjVAJzZuQkL7Mfqejnby7CNgkSk0FFS4top/6EQoe+NeQj1zcDCQQ4/ze5sahc0CF7aaPsq1+aI17CCBh2PFUOvG9/YM5Hj7An2cDURChHr0OJjT8/QwqR49cSSS5P4yhaVxOQqszUAinV+r5FtLGo7iXSMnE/XYV0vpZqJHAD9cPyymcl2N7v1dKWBTmamEp7GsM6T7YnDtSJIeYt9cTi+0IFYMPAe+W93zgH2g/r+nmL/eZapgUD5Gi2ky1bHe0vwn8wIDAQABAoIBQBJ7JYYCt+kiZLNWqQ0rK9Aw8O5wWgdCQ/Di0EgKpox0KO4WpS9+LzYheiCvwd4YqYWnHBasSv3T/nt3X7oTTDYb5v0WzFWrIyE3qmWBjPiGDFrojXEDab7k9X9LwrIEfU0407lbWJapQVPLVYo63CsB1aKudEMvWgDXLy1v59475zJdduBRq5yjVGEZ/U9FmbqYfMcddTBpLf2oqlEjh5r10BWONOKx6tpUd/ALBgC34XNSUgRF6Q+D80hkayzO0s+ZAOH5dZCQydyGhh5xHdnscq9SRNvonmh4FtbkMAcsl81OkkB35jCnbqN3Ms8PbdzHDwujH/Bs2zvnuOovgce2Uo6U3/r39XZT2Jy7u34aUjSeLGvyldNsSf9Krwzt4xru0TFB+Zj/J0YapV1WfNv4M7Y9c3UMu+UpM4CnOVB5AoGhAPS5rO2gYJw3zeCfqgEFuExuZqMbZXRLap/fyA5ERpm8+oHabi+Yow1e1Lj+jHL7y1x0o1l0HAkzG9QnM3+pVBV0dlF7hSBHG1h5ajcOMqnjTB2Q4IzCUhAGvwbG2ZZn6E1KJUs+1PulqTnubZMiXQm7AbjAzBbhc0yFDnh7cZSF2oKKNsjsMgRs2zUoiPipMqIa+cyu2dbBxOur2viaXcUCgaEA10q4FWfQLFwcbso6VgaL0im1yp1SXRCqoZ6CeL6A2LyZScJ7fupHVBguIxFaMIZTGFHuGgVMti/MIYfThZM386Z8gL8LoAqp95OgKsm2WGyFca6rvrlJhmLGAgxULrU0HQ9eDNw/4jGVTmuW9OG0yfBJFABW1G9fsjJNSHyjxbX4p8e88RXn6AWU8KIgPcTeyYiYW7oeycEOQKXBRAvCVwKBoHxqIPY1wKfq3unBgkY+yDFjNx7ZAL0c0joxJJ3MLDBgmOKHT9k2uj5D5dWe43xZckuwqJMDqnUq3I0A2Pef+DVoHfbS2x1LySUzpMIUn8Eq4zlsvBwTdnDbXSZu1ZPXg4w3k7orWVAOKnhfNKnGoJIf1oI80gUX3OwcAP1TlKyzWCFhbvS6z7rcNJ1T3D6+lhU/rZtXkTvTCu/dUNducxkCgaEAmF+ZygyfmcXXmdInV5tqemRq9exCzvtsyNaXIT4zkzJoi3vKTBkkQrCadtdhLdbkGOJj0qbNlGRf5Ztsaa24fAnpNHYClFL32PHy+lWpaQvlpoApreMV1rcxzWFMc4JsT+UAe7mmvUC6m7YqMUdN3V7jWfSjf9cTs9tGN3d/sf8I7ja/0yHd8KmCsI0OpKkhxSGYM9OW1tR8ceTe1Ho+IQKBoQDELzIIUG4ND9QuvgwJUW0ys4Xo1BX5wNWP77GasAEb9EYB1uF7Apcp8yfGax+pRuqd/t0e5HDcd4JOhwfcWHAZYQqEm6d9yxq+eE0o/junEIVEPggNgcq3xJTryhq7kpzduj8GDdbq8PjuMFouJezjYHnbcidqAgLNfofqkj9cxAn5xIg2jhMIJh8RUqFlNEp8EKulTlGVTA8sj8Lf2Z1B", Base64.DEFAULT); 
     PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(encoded); 
     RSAPrivateKey debugprivateKey = (RSAPrivateKey) fact.generatePrivate(privateKeySpec); 

// selftest (encrypt data) 
     String OutPutEncryption = "debug.exponent.javatest2.txt"; 
     CheckCipher.init(Cipher.ENCRYPT_MODE, publicKey); 
     DataOutputStream cryptFile = new DataOutputStream(new FileOutputStream(OutPutEncryption)); 
     byte[] decryptedBuffer = new byte[] {100, 110, 112, 99, 64}; // some data 5 bytes 
     CheckCipher.doFinal(decryptedBuffer, 0, 5, encryptedBuffer); 
     cryptFile.write(encryptedBuffer); 
     cryptFile.close(); 

// decrypt data from selftext or external source 
     String SourceFile = "debug.exponent.javatest2.txt"; 
     CheckCipher.init(Cipher.DECRYPT_MODE, debugprivateKey); 
     DataInputStream readCryptFileDeb = new DataInputStream(new FileInputStream(SourceFile)); 
     readCryptFileDeb.read(encryptedBuffer); 
     readCryptFileDeb.close(); 
     byte[] Test = CheckCipher.doFinal(encryptedBuffer); 
     System.out.println(new String(Test)); 
    } 
} 

Answer 1

不幸的是我目前還沒有運行Android系統來測試它，但我猜想可能會選擇不同的填充算法。

所以給它一個嘗試，explicitley選擇填充算法，像這樣：

Cipher CheckCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); 

請注意，您還可以選擇在這種情況下，一個塊鏈接模式。在這種情況下，我選擇了「ECB」（=無塊鏈接），因爲我認爲這是默認值。