KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128); // 192 and 256 bits may not be available
在 Eclipse 中，当我选择KeyGenerator并右键单击打开声明时，我打开了一个窗口。
单击此处查看错误图像（图像链接已损坏）
你能解释一下这里有什么问题吗？顺便说一句，这是完整的代码
package org.temp2.cod1;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.io.*;
/**
* This program generates a AES key, retrieves its raw bytes, and
* then reinstantiates a AES key from the key bytes.
* The reinstantiated key is used to initialize a AES cipher for
* encryption and decryption.
*/
public class AES1
{
/**
* Turns array of bytes into string
*
* @param buf Array of bytes to convert to hex string
* @return Generated hex string
*/
public static String asHex (byte buf[])
{
StringBuffer strbuf = new StringBuffer(buf.length * 2);
int i;
for (i = 0; i < buf.length; i++)
{
if (((int) buf[i] & 0xff) < 0x10)
strbuf.append("0");
strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
}
return strbuf.toString();
}
public static void main(String[] args) throws Exception
{
String message="This is just an example";
// Get the KeyGenerator
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128); // 192 and 256 bits may not be available
// Generate the secret key specs.
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
// Instantiate the cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted =
cipher.doFinal((args.length == 0 ?
"This is just an example" : args[0]).getBytes());
System.out.println("encrypted string: " + asHex(encrypted));
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] original =
cipher.doFinal(encrypted);
String originalString = new String(original);
System.out.println("Original string: " +
originalString + " " + asHex(original));
}
}