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用范例出错

lping9188

发贴: 0
积分: 0

于 2003-03-05 21:01

我试着下面程序：
import java.security.*;
import javax.crypto.*;

class crypto1
{
   public static void main(String[] args)
{

   try
   {
   KeyGenerator keygen = KeyGenerator.getInstance("DES");
SecretKey desKey = keygen.generateKey();
}
catch(NoSuchAlgorithmException e)
{

System.out.println("Failed to generate key");
System.exit(1);
}

Cipher desCipher;

// Create the cipher

try
{
desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
}
catch(NoSuchAlgorithmException e)
   {

   System.out.println("Failed to get instance");
   System.exit(1);
}

// Initialize the cipher for encryption

try
{
   desCipher.init(Cipher.ENCRYPT_MODE,desKey);
}

   catch(InvalidKeyException e)
   {

   System.out.println("Failed to initial cipher");
   System.exit(1);
}

   // Our cleartext
   byte[] cleartext = "This is just an example".getBytes();

   // Encrypt the cleartext
   try
   {
   byte[] ciphertext = desCipher.doFinal(cleartext);
   }

   catch(IllegalBlockSizeException e)
      {

      System.out.println("Failed to generate key");
      System.exit(1);
}

// Initialize the same cipher for decryption
try
{

   desCipher.init(Cipher.DECRYPT_MODE,desKey);
   }
   catch(InvalidKeyException e)
       {

       System.out.println("Failed to generate key");
       System.exit(1);
}

   try
   {
   // Decrypt the ciphertext
byte[] cleartext1 = desCipher.doFinal(ciphertext);
   }
catch(IllegalBlockSizeException e)
      {

      System.out.println("Failed to generate key");
      System.exit(1);
}
System.out.println("success");

}
}

编译结果为：
C:\java\crypto1.java:42: cannot resolve symbol
symbol : variable desKey
location: class crypto1
   desCipher.init(Cipher.ENCRYPT_MODE,desKey);
^
C:\java\crypto1.java:74: cannot resolve symbol
symbol : variable desKey
location: class crypto1
   desCipher.init(Cipher.DECRYPT_MODE,desKey);
^
C:\java\crypto1.java:86: cannot resolve symbol
symbol : variable ciphertext
location: class crypto1
byte[] cleartext1 = desCipher.doFinal(ciphertext);
^
3 errors
不知为何，我用的是jdk1.3.1,按照说明安装了jce
多谢！

作者	Re:用范例出错 [Re:lping9188]
menzy 版主发贴: 754 积分: 113	于 2003-03-06 17:40 ok, your definition of variables are in "try" block, and it wouldn't work outside it, so the Java VM cannot find the definition of variables.

作者	Re:用范例出错 [Re:lping9188]
lping9188 发贴: 0 积分: 0	于 2003-03-08 23:05 Thanks alot!

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