I am doing encryption and decryption of data as follows but getting error
我正在对数据进行加密和解密，但是会出错。
protected Cipher aes_Gen_with_Key(byte[] key)
{
Cipher cipher=null;
try
{
byte[] key_hash = (key).toString().getBytes("UTF-8");
key_hash = Arrays.copyOf(key_hash, 32); // use only first 256 bit
SecretKeySpec secretKeySpec = new SecretKeySpec(key_hash, "AES");
cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
} catch (Exception e) {
System.out.println("Error Occured");
}
return cipher;
}
protected Cipher aes_Dec_with_Key(byte[] key,byte[] iv)
{
Cipher cipher=null;
try
{
byte[] key_hash = (key).toString().getBytes("UTF-8");
key_hash = Arrays.copyOf(key_hash, 32); // use only first 256 bit
SecretKeySpec secretKeySpec = new SecretKeySpec(key_hash, "AES");
cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE,secretKeySpec,new IvParameterSpec(iv));
}
catch (Exception e) {
System.out.println(e);
}
return cipher;
}
With above 2 functions I am getting ciphers with which I am doing encryption and decryption, but getting javax.crypto.BadPaddingException: Given final block not properly padded as error. Length of decryption byte array is 752 and IV at decryption is 16 byte long. Can any one suggest?
通过以上两个函数，我得到了加密和解密的密码，但是得到了javax.crypto。BadPaddingException:给定最终块不正确填充为错误。解密字节数组的长度为752，而解密的IV则为16字节长。任何一个建议吗?
Here are few more relevant code blocks. Apologies for invalid use java naming conventions
下面是几个相关的代码块。对无效的使用java命名约定的道歉。
// Key Class
import java.io.Serializable;
@SuppressWarnings("serial")
public class Key implements Serializable{
byte[] gsmodp_hash=null;
byte[] iv_pass=null;
byte[] Nonce_Enc=null;
byte[] iv_non=null;
public Key() {
}
public Key(byte[] gsmodp_hash,byte[] iv_pass,byte[] Nonce_Enc,byte[] iv_non) {
this.gsmodp_hash=gsmodp_hash;
this.iv_pass=iv_pass;
this.Nonce_Enc=Nonce_Enc;
this.iv_non=iv_non;
}
}
// Client side code
JSONObject auth_step_obj=new JSONObject();
try {
BigInteger gsmodp=get_modu_frm_server(receivePacket);
BigInteger R2=get_R2_frm_server(receivePacket);
BigInteger N2=get_N2_frm_server(receivePacket);
N2=crypto.dec_NonceG(N2);
BigInteger a=crypto.get_RandLong();
BigInteger gamodp= crypto.dh_GenerationG(a, crypto.g, crypto.p);
BigInteger key=crypto.dh_GenerationG(a, gsmodp, crypto.p);
// Got hash of g^abmodp
byte[] dhkey=crypto.sha256G(key.toString());
key=null;
//Mixing passwords
SecretKey secretkey=(SecretKey) userCredentials.get("password");
byte[] mixed_hash=crypto.passwordMixerG(R2, secretkey.getEncoded());
//Working Fine Till now
// Getting Cipher for encrypting gsmodp using password and nonce
Cipher cipher_password=crypto.aes_Gen_with_Key(mixed_hash);
Cipher cipher_key=crypto.aes_Gen_with_Key(dhkey);
// Generating quantities for JSON Object
byte[] gsmodp_hash=cipher_password.doFinal(gamodp.toString().getBytes());
byte[] gsmodp_hash_iv=cipher_password.getIV();
byte[] nonce_enc=cipher_key.doFinal(N2.toString().getBytes());
byte[] nonce_enc_iv=cipher_key.getIV();
Key authetication_parameters=new Key(gsmodp_hash,gsmodp_hash_iv,nonce_enc,nonce_enc_iv);
auth_step_obj.put("obj",authetication_parameters);
} catch (Exception e) {
// TODO Auto-generated catch block
System.out.println("Hi:sec_DH_Step");
}
// This sends JSONObject to calling method which generates UDP packet and sends to server
return auth_step_obj;
}
// Server side code
// Once packet received on server following happens
ds.receive(receivePacket);
SecretKey userKey=cryptoObj.get_from_KeyStoreG(user_name);
// Adding R2 and userKey byte by byte
byte[] mixed_hash=cryptoObj.passwordMixerG(R2, userKey.getEncoded());
JSONObject authentication_nonce=new JSONObject();
authentication_nonce=cryptoObj.readRecievedPacket(receivePacket);
Key obj=(Key)authentication_nonce.get("obj");
Cipher cipher=cryptoObj.aes_Dec_with_Key(mixed_hash,obj.iv_pass);
// I am getting error on do final
System.out.println(new String(cipher.doFinal(obj.gsmodp_hash)));
1 个解决方案
#1
3
The code you presented works just fine. The error must lie in the code you haven't shared with us (i.e. the code that actually uses the Cipher objects).
你提交的代码很好。错误必须位于您没有与我们共享的代码(即实际使用密码对象的代码)。
I wrote the code below to test your question code:
我写了下面的代码来测试你的问题代码:
public static void main(String[] args) throws Exception {
Random random = new Random();
byte[] key = new byte[32];
random.nextBytes(key);
byte[] plaintext = new byte[100];
random.nextBytes(plaintext);
Cipher enc = aes_Gen_with_Key(key);
byte[] ciphertext = enc.doFinal(plaintext);
byte[] iv = enc.getIV();
Cipher dec = aes_Dec_with_Key(key, iv);
byte[] recoveredPlaintext = dec.doFinal(ciphertext);
System.out.println(Arrays.equals(plaintext, recoveredPlaintext));
}
Note, I made your two methods static. You should do the same, as they don't use any instance variables.
注意，我让您的两个方法是静态的。您应该这样做，因为它们不使用任何实例变量。
#1
3
The code you presented works just fine. The error must lie in the code you haven't shared with us (i.e. the code that actually uses the Cipher objects).
你提交的代码很好。错误必须位于您没有与我们共享的代码(即实际使用密码对象的代码)。
I wrote the code below to test your question code:
我写了下面的代码来测试你的问题代码:
public static void main(String[] args) throws Exception {
Random random = new Random();
byte[] key = new byte[32];
random.nextBytes(key);
byte[] plaintext = new byte[100];
random.nextBytes(plaintext);
Cipher enc = aes_Gen_with_Key(key);
byte[] ciphertext = enc.doFinal(plaintext);
byte[] iv = enc.getIV();
Cipher dec = aes_Dec_with_Key(key, iv);
byte[] recoveredPlaintext = dec.doFinal(ciphertext);
System.out.println(Arrays.equals(plaintext, recoveredPlaintext));
}
Note, I made your two methods static. You should do the same, as they don't use any instance variables.
注意，我让您的两个方法是静态的。您应该这样做，因为它们不使用任何实例变量。