Java：算法RSA的關鍵不適合對稱加密。

Question

我想用AES/CBC加密文件，密鑰必須是隨機的，並用RSA加密。 我得到了「算法RSA的關鍵不適用於對稱加密。」......似乎是什麼問題？

這是我的代碼部分：這裏

KeyGenerator keyGen = KeyGenerator.getInstance("AES", "BC"); 
keyGen.init(256); 
Key key = keyGen.generateKey(); 

，您可以：

Security.addProvider(new BouncyCastleProvider()); 
    byte[] input = "Encryption Test".getBytes(); 
    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding", "BC"); // init Cipher to use AES/CBC 
    SecureRandom random = new SecureRandom(); // IV is random 
    KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA", "BC"); // Key will be generated with RSA 

    generator.initialize(512, random); 
    KeyPair pair = generator.generateKeyPair(); 
    Key pubKey = pair.getPublic(); 
    //Key privKey = pair.getPrivate(); 

    cipher.init(Cipher.ENCRYPT_MODE, pubKey, random); 

Answer 1

不能使用帶有AES加密RSA密鑰...

使用這種替代找到一個code example.

Answer 2

恭喜希望使用密鑰交換密碼k EY-交流！有時我想知道爲什麼這麼多人在互聯網上試圖把RSA變成流密碼。

下面的示例代碼顯示瞭如何執行此操作。

import javax.crypto.Cipher; 
import javax.crypto.KeyGenerator; 
import javax.crypto.SecretKey; 
import javax.crypto.spec.IvParameterSpec; 
import javax.crypto.spec.SecretKeySpec; 

import java.io.*; 
import java.security.*; 
import java.security.spec.PKCS8EncodedKeySpec; 
import java.security.spec.X509EncodedKeySpec; 

public class Test { 

    /** 
    * Generate an RSA key pair and save it to the file 
    */ 
    public static KeyPair genKeys(File keyFile) throws Exception { 
     System.out.println("Generating RSA keys"); 

     KeyFactory factory = KeyFactory.getInstance("RSA"); 
     KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA"); 
     kpg.initialize(2048); 
     KeyPair kp = kpg.generateKeyPair(); 
     X509EncodedKeySpec pubSpec = factory.getKeySpec(kp.getPublic(), 
       X509EncodedKeySpec.class); 
     PKCS8EncodedKeySpec privSpec = factory.getKeySpec(kp.getPrivate(), 
       PKCS8EncodedKeySpec.class); 

     FileOutputStream out = new FileOutputStream(keyFile); 
     DataOutputStream dat = new DataOutputStream(out); 

     byte[] enc = pubSpec.getEncoded(); 
     dat.writeInt(enc.length); 
     dat.write(enc); 

     enc = privSpec.getEncoded(); 
     dat.writeInt(enc.length); 
     dat.write(enc); 
     dat.flush(); 
     dat.close(); 

     System.out.println("RSA keys saved to " + keyFile.getPath()); 

     return kp; 
    } 


    /** 
    * Load an RSA key pair from the file 
    */ 
    public static KeyPair loadKeys(File keyFile) throws Exception { 
     System.out.println("Loading RSA keys"); 

     FileInputStream in = new FileInputStream(keyFile); 
     DataInputStream dat = new DataInputStream(in); 

     int len = dat.readInt(); 
     byte[] enc = new byte[len]; 
     dat.readFully(enc); 
     X509EncodedKeySpec pubSpec = new X509EncodedKeySpec(enc); 

     len = dat.readInt(); 
     enc = new byte[len]; 
     dat.readFully(enc); 
     PKCS8EncodedKeySpec privSpec = new PKCS8EncodedKeySpec(enc); 

     dat.close(); 

     KeyFactory factory = KeyFactory.getInstance("RSA"); 
     PublicKey pub = factory.generatePublic(pubSpec); 
     PrivateKey priv = factory.generatePrivate(privSpec); 

     System.out.println("RSA keys loaded from " + keyFile.getPath()); 
     return new KeyPair(pub, priv); 
    } 


    /** 
    * Decrypt a file 
    */ 
    public static void decrypt(KeyPair kp, File inFile, File outFile) throws Exception { 
     Cipher rsa = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding"); 

     FileInputStream in = new FileInputStream(inFile); 
     DataInputStream dat = new DataInputStream(in); 

     // read RSA encrypted AES key 
     int len = dat.readInt(); 
     byte[] buf = new byte[len]; 
     dat.readFully(buf); 
     rsa.init(Cipher.DECRYPT_MODE, kp.getPrivate()); 

     SecretKeySpec key = new SecretKeySpec(rsa.doFinal(buf), "AES"); 

     // read the AES IV 
     len = dat.readInt(); 
     buf = new byte[len]; 
     dat.readFully(buf); 
     IvParameterSpec iv = new IvParameterSpec(buf); 

     Cipher aes = Cipher.getInstance("AES/CBC/PKCS5Padding"); 
     aes.init(Cipher.DECRYPT_MODE, key, iv); 

     // process the rest of the file to get the original back 
     FileOutputStream out = new FileOutputStream(outFile); 

     buf = new byte[1000]; 
     int r = -1; 
     while((r = dat.read(buf)) != -1) { 
      byte[] sec = aes.update(buf, 0, r); 
      if (sec != null) out.write(sec); 
     } 
     out.write(aes.doFinal()); 
     out.flush(); 
     out.close(); 
     in.close(); 
    } 


    public static void encrypt(KeyPair kp, File inFile, File outFile) throws Exception { 
     Cipher rsa = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding"); 

     // create new AES key 
     KeyGenerator gen = KeyGenerator.getInstance("AES"); 
     gen.init(256); 
     SecretKey key = gen.generateKey(); 

     // RSA encrypt AES key 
     byte[] keyEnc = key.getEncoded(); 
     rsa.init(Cipher.ENCRYPT_MODE, kp.getPublic()); 
     byte[] keySec = rsa.doFinal(keyEnc); 

     // Create AES cipher 
     Cipher aes = Cipher.getInstance("AES/CBC/PKCS5Padding"); 
     aes.init(Cipher.ENCRYPT_MODE, key); 
     byte[] iv = aes.getIV(); 

     FileOutputStream out = new FileOutputStream(outFile); 
     DataOutputStream dat = new DataOutputStream(out); 

     // save encrypted AES key and IV 
     dat.writeInt(keySec.length); 
     dat.write(keySec); 
     dat.writeInt(iv.length); 
     dat.write(iv); 

     // save the encrypted file 
     FileInputStream in = new FileInputStream(inFile); 
     byte[] buf = new byte[1000]; 
     int r = -1; 
     while((r = in.read(buf)) != -1) { 
      byte[] sec = aes.update(buf, 0, r); 
      if (sec != null) dat.write(sec); 
     } 
     dat.write(aes.doFinal()); 
     dat.flush(); 
     dat.close(); 
     in.close(); 
    } 


    /** 
    * @param args 
    */ 
    public static void main(String[] args) throws Exception { 
     if (args.length != 4) { 
      System.out.println("Usage: java Test (encrpyt|decrypt) keyFile inFile outFile"); 
      return; 
     } 
     KeyPair kp; 
     File keyFile = new File(args[0]); 
     if (!keyFile.canRead()) { 
      kp = genKeys(keyFile); 
     } else { 
      kp = loadKeys(keyFile); 
     } 

     boolean isEnc = args[1].equalsIgnoreCase("encrypt"); 
     boolean isDec = args[1].equalsIgnoreCase("decrypt"); 
     File inFile = new File(args[2]); 
     File outFile = new File(args[3]); 
     if (!(isEnc || isDec) || !inFile.canRead()) { 
      System.out.println("Usage: java Test (encrpyt|decrypt) keyFile inFile outFile"); 
      return; 
     } 

     if (isEnc) { 
      encrypt(kp, inFile, outFile); 
     } else { 
      decrypt(kp, inFile, outFile); 
     } 
    } 
}