我是密码学的新手,所以我有一个问题:
我如何创建自己的 key (比如说字符串“1234”)。因为我需要用一个 key (由我定义)来加密一个字符串,所以将加密后的字符串保存在数据库中,当我想使用它时,从数据库中取出它并用我知道的 key 对其进行解密。
我有这段代码:
import java.security.InvalidKeyException;
import java.security.*;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
public class LocalEncrypter {
private static String algorithm = "PBEWithMD5AndDES";
//private static Key key = null;
private static Cipher cipher = null;
private static SecretKey key;
private static void setUp() throws Exception {
///key = KeyGenerator.getInstance(algorithm).generateKey();
SecretKeyFactory factory = SecretKeyFactory.getInstance(algorithm);
String pass1 = "thisIsTheSecretKeyProvidedByMe";
byte[] pass = pass1.getBytes();
SecretKey key = factory.generateSecret(new DESedeKeySpec(pass));
cipher = Cipher.getInstance(algorithm);
}
public static void main(String[] args)
throws Exception {
setUp();
byte[] encryptionBytes = null;
String input = "1234";
System.out.println("Entered: " + input);
encryptionBytes = encrypt(input);
System.out.println(
"Recovered: " + decrypt(encryptionBytes));
}
private static byte[] encrypt(String input)
throws InvalidKeyException,
BadPaddingException,
IllegalBlockSizeException {
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] inputBytes = input.getBytes();
return cipher.doFinal(inputBytes);
}
private static String decrypt(byte[] encryptionBytes)
throws InvalidKeyException,
BadPaddingException,
IllegalBlockSizeException {
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] recoveredBytes =
cipher.doFinal(encryptionBytes);
String recovered =
new String(recoveredBytes);
return recovered;
}
Exception in thread "main" java.security.spec.InvalidKeySpecException: Invalid key spec
at com.sun.crypto.provider.PBEKeyFactory.engineGenerateSecret(PBEKeyFactory.java:114)
at javax.crypto.SecretKeyFactory.generateSecret(SecretKeyFactory.java:335)
at LocalEncrypter.setUp(LocalEncrypter.java:22)
at LocalEncrypter.main(LocalEncrypter.java:28)
最佳答案
KeyGenerator 生成随 secret 钥。因为您知道 key ,所以您需要的是 SecretKeyFactory 。为您的算法 (DESede) 获取一个实例,然后使用 DESedeKeySpec 实例作为参数调用其 generateSecret 方法:
SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
SecretKey key = factory.generateSecret(new DESedeKeySpec(someByteArrayContainingAtLeast24Bytes));
这是一个完整的有效示例。正如我所说,DESedeKeySpec 必须与 DESede 算法一起使用。将 DESede key 与 PBEWithMD5AndDES 一起使用是没有意义的。
public class EncryptionTest {
public static void main(String[] args) throws Exception {
byte[] keyBytes = "1234567890azertyuiopqsdf".getBytes("ASCII");
DESedeKeySpec keySpec = new DESedeKeySpec(keyBytes);
SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
SecretKey key = factory.generateSecret(keySpec);
byte[] text = "Hello world".getBytes("ASCII");
Cipher cipher = Cipher.getInstance("DESede");
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] encrypted = cipher.doFinal(text);
cipher = Cipher.getInstance("DESede");
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decrypted = cipher.doFinal(encrypted);
System.out.println(new String(decrypted, "ASCII"));
}
}
关于java - 加密解密我自己的 key 未生成java,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8300720/