解密JSON Web加密中的内容加密密钥

我正在使用OpenSSL RSA1_5解密CEK（内容加密密钥）。解密JSON Web加密中的内容加密密钥

我的目标是解密我将获得CEK的JWK（JSON Web Key），所以通过使用CEK，我可以解密我的密文，这实际上是加密数据。

使用Base64Decode后，JWE部首是

{"alg":"RSA1_5","enc":"A128CBC-HS256","typ":"JOSE"}

其中 “ALG” 是用于解密CEK的算法。请帮我先解密CEK，之后我需要解密密码。

我的Java类是：

package com.decryption; 

import java.io.*; 
import java.math.BigInteger; 

import java.security.*; 
import java.security.spec.*; 
import java.security.interfaces.*; 

import javax.crypto.*; 
import javax.crypto.spec.*; 
import javax.crypto.interfaces.*; 

public class RSADecrypt 
{ 
    public RSADecrypt(String inFileName, String outFileName) { 


     try { 
      System.out.println("Inside TRY"); 
     /* Get the encrypted message from file. */ 
     FileInputStream cipherfile = new FileInputStream(inFileName); 
     byte[] ciphertext = new byte[cipherfile.available()]; 
     cipherfile.read(ciphertext); 
     cipherfile.close(); 
     System.out.println("Inside 1"); 
     /* Get the private key from file. */ 
     //PrivateKey privatekey = readPrivateKey("D://sso//mmdevnopass.key"); 
     PrivateKey privatekey = readPrivateKey("D://sso//mmdevJWE.key"); 
     System.out.println("Inside 2"); 

     /* Create cipher for decryption. */ 
     Cipher decrypt_cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); 
     decrypt_cipher.init(Cipher.DECRYPT_MODE, privatekey); 
     System.out.println("Inside 3"); 
     /* Reconstruct the plaintext message. */ 
     byte[] plaintext = decrypt_cipher.doFinal(ciphertext); 
     FileOutputStream plainfile = new FileOutputStream(outFileName); 
     plainfile.write(plaintext); 
     plainfile.close(); 
     } catch (Exception e) { 
      System.out.println("catch1"); 
     e.printStackTrace(); 
     } 
    } 

    public static PrivateKey readPrivateKey(String filename) throws Exception { 
     System.out.println("readPrivateKey()"); 
     FileInputStream file = new FileInputStream(filename); 
     byte[] bytes = new byte[file.available()]; 
     file.read(bytes); 
     file.close(); 
     System.out.println("readPrivateKey() 1"); 
     PKCS8EncodedKeySpec privspec = new PKCS8EncodedKeySpec(bytes); 
    // X509EncodedKeySpec privspec= new X509EncodedKeySpec(bytes); 
     //RSAPrivateKeySpec privspec = new RSAPrivateKeySpec(modulus, privateExponent) 
     System.out.println("readPrivateKey() 2"); 
     KeyFactory factory = KeyFactory.getInstance("RSA"); 
     System.out.println("readPrivateKey() 3"); 
     PrivateKey privkey = factory.generatePrivate(privspec); 
     System.out.println("readPrivateKey() 4"); 
     return privkey; 
    } 

    public static void main(String[] arg) { 
     /*if (arg.length != 2) { 
     System.err.println("Usage: java RSADecrypt <src file> <dest file>"); 
     } else {*/ 
     System.out.println("Welcome"); 
     String inFileName="D://sso//myJEK.txt"; 
     String outFileName="D://sso//out.txt"; 
     new RSADecrypt(inFileName,outFileName); 
    // } 
    } 
}

我得到输出

Welcome 
Inside TRY 
Inside 1 
readPrivateKey() 
readPrivateKey() 1 
readPrivateKey() 2 
readPrivateKey() 3 
java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: invalid key format 
    at sun.security.rsa.RSAKeyFactory.engineGeneratePrivate(RSAKeyFactory.java:175) 
    at java.security.KeyFactory.generatePrivate(KeyFactory.java:322) 
    at com.decryption.RSADecrypt.readPrivateKey(RSADecrypt.java:85) 
    at com.decryption.RSADecrypt.<init>(RSADecrypt.java:46) 
    at com.decryption.RSADecrypt.main(RSADecrypt.java:102) 
Caused by: java.security.InvalidKeyException: invalid key format 
    at sun.security.pkcs.PKCS8Key.decode(PKCS8Key.java:324) 
    at sun.security.pkcs.PKCS8Key.decode(PKCS8Key.java:350) 
    at sun.security.rsa.RSAPrivateCrtKeyImpl.<init>(RSAPrivateCrtKeyImpl.java:74) 
    at sun.security.rsa.RSAPrivateCrtKeyImpl.newKey(RSAPrivateCrtKeyImpl.java:58) 
    at sun.security.rsa.RSAKeyFactory.generatePrivate(RSAKeyFactory.java:274) 
    at sun.security.rsa.RSAKeyFactory.engineGeneratePrivate(RSAKeyFactory.java:171) 
    ... 4 more 
catch1

请帮我解密CEK并解决此异常。

来源

2014-03-27 Vasu Dev

您的问题是由您的私钥文件造成的。首先，您读取字节的方法容易出错：

FileInputStream file = new FileInputStream(filename); 
byte[] bytes = new byte[file.available()]; 
file.read(bytes); 
file.close();

这可能不会读取整个文件。 available()方法确实而不是指示文件中有多少个字节。请搜索更好的方式阅读此文件（也许从这个问题：File to byte[] in Java）。

修复此问题后，除非文件是DER编码的PKCS＃8对象，否则可能仍然存在错误。一个常见的错误是尝试使用PEM编码文件（例如，包含----- BEGIN PRIVATE KEY ----标头和base64编码数据）。

来源

2014-03-27 11:30:54

解密JSON Web加密中的内容加密密钥

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