我正在尝试使用具有两个不同密钥的三重DES加密数据,因此给定两个密钥k1和k2,加密文本将为Ek1(Dk2(Ek1(plaintext))),其中E为加密和D解密。我正在尝试使用Java的DES算法对此进行仿真。这是代码:
public static void main(String[] args) {
SecretKey k1 = generateDESkey();
SecretKey k2 = generateDESkey();
String firstEncryption = desEncryption("plaintext", k1);
String decryption = desDecryption(firstEncryption, k2);
String secondEncryption = desEncryption(decryption, k1);
}
public static SecretKey generateDESkey() {
KeyGenerator keyGen = null;
try {
keyGen = KeyGenerator.getInstance("DES");
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
}
keyGen.init(56); // key length 56
SecretKey secretKey = keyGen.generateKey();
return secretKey;
}
public static String desEncryption(String strToEncrypt, SecretKey desKey) {
try {
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, desKey);
String encryptedString = Base64.encode(cipher.doFinal(strToEncrypt.getBytes()));
return encryptedString;
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchPaddingException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (IllegalBlockSizeException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (BadPaddingException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidKeyException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
public static String desDecryption(String strToDecrypt, SecretKey desKey) {
try {
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5PADDING");
cipher.init(Cipher.DECRYPT_MODE, desKey);
String decryptedString = new String(cipher.doFinal(Base64.decode(strToDecrypt)));
return decryptedString;
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchPaddingException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidKeyException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (IllegalBlockSizeException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (BadPaddingException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
} catch (Base64DecodingException ex) {
Logger.getLogger(Test.class
.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
我有这个错误:javax.crypto.BadPaddingException:在尝试在以下代码行解密时,给定的最终块未正确填充:
String decryptedString = new String(cipher.doFinal(Base64.decode(strToDecrypt)));
您能帮我解决这个问题吗,还是您知道一种直接方法,该方法使用具有两个不同密钥且总密钥长度为128位的三重DES加密数据?我没有找到任何算法,因此尝试使用简单的DES对其进行仿真。
为什么不只使用随附的DESede算法?
将所有DES代码实例更改为DESede,并将密钥生成方法更改为:
public static SecretKey generateDESkey() {
KeyGenerator keyGen = null;
try {
keyGen = KeyGenerator.getInstance("DESede");
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
}
keyGen.init(112); // key length 112 for two keys, 168 for three keys
SecretKey secretKey = keyGen.generateKey();
return secretKey;
}
请注意,DESede现在如何提供getInstance()方法,并且密钥大小已增加到112(三个密钥为168)。
从以下位置更改您的密码实例:
Cipher.getInstance("DES/ECB/PKCS5Padding");
到
Cipher.getInstance("DESede/ECB/PKCS5Padding");
然后你就定了。
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