Bad Padding Výnimka pri dešifrovaní - java, cryptography, passwords, aes

Snažím sa implementovať šifrovací algoritmus založený na hesle, ale dostávam túto výnimku:

javax.crypto.BadPaddingException: Vzhľadom na to, že posledný blok nie je správne vyplnený.

Aký môže byť problém? (Som nový jazyk Java.) Tu je môj kód:

import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;

public class EfiAdminPasswordHasher {
/** SIZE variable.*/
private static final int SIZE = 16;
/** The serial number. */
private static final long serialVersionUID = -7930024972049607076L;
private static final String SECRET_KEY = "Dp29eInG$fch@ujO";
private static final String SALT = "I@j2ts_@p$c29qTw";
private SecretKey secretKey;


public EfiAdminPasswordHasher() {
generateSecretKey();
}

private void generateSecretKey() {
try {

SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(SECRET_KEY.toCharArray(),
SALT.getBytes(), 65536, 256);
SecretKey keySpec = factory.generateSecret(spec);
final SecretKey secret = new SecretKeySpec(keySpec.getEncoded(),
"AES");
System.out.println(secret+" "+"In SECRET kEY");
secretKey = secret;
} catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
throw new IllegalStateException(
"EfiAdminPasswordHasher::decryptPassword() - Unable to decrypt password.",
e);
}
}


public String encryptPassword(String password) {
if (password == null || password.trim().length() == 0) {
return password;
}
// Encoding password with SHA-256 algorithm
try {

MessageDigest md = MessageDigest.getInstance("SHA-256");
md.update(password.getBytes());

byte byteData[] = md.digest();
//convert the byte to hex format method 1
StringBuilder sb = new StringBuilder();
for (int i = 0; i < byteData.length; i++) {
sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
}
return sb.toString();

} catch (NoSuchAlgorithmException | IllegalStateException e) {
throw new IllegalStateException(
"EfiAdminPasswordHasher::encryptPassword() - Unable to encrypt password.",
e);
}
}


public String decryptPassword(String encryptedPassword) {

// Cannot use StringUtils here, because this class to be serialized and
// sent over to ACC
if (encryptedPassword == null || encryptedPassword.trim().length() == 0) {
return encryptedPassword;
}
// DECODE encryptedPwd String
try {
final byte[] encrypedPwdBytes = Base64.decodeBase64(encryptedPassword.getBytes());
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

byte[] iv = new byte[SIZE];
cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(iv));

final byte[] plainTextPwdBytes = cipher.doFinal(encrypedPwdBytes);

return new String(plainTextPwdBytes);
} catch (IllegalBlockSizeException | NoSuchAlgorithmException | NoSuchPaddingException |
InvalidKeyException | IllegalStateException | BadPaddingException |
InvalidAlgorithmParameterException e) {
throw new IllegalStateException(
"EfiAdminPasswordHasher::decryptPassword() - Unable to decrypt password.",
e);
}
}


public static void main(String[] args) {
EfiAdminPasswordHasher hasher = new EfiAdminPasswordHasher();
String encryptedPassword=hasher.encryptPassword("2");
System.out.println("Encrypted password"+" "+encryptedPassword);


String decryptedPassword=hasher.decryptPassword(encryptedPassword);
System.out.println("Decrypted password"+" "+decryptedPassword);

}
}

odpovede:

Riešenie som našiel v inom príspevku tu, skúste to urobiť:

final byte[] encrypedPwdBytes = fromHexString(encryptedPassword);
//...
public static byte[] fromHexString(String s) {
int len = s.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+ Character.digit(s.charAt(i+1), 16));
}
return data;
}