Im machen App zum Verschlüsseln und Entschlüsseln von Text im AES/CBC-Modus. In AES/CBC/PKCS5Padding (und PKCS7Padding) funktioniert alles gut, aber wenn ich den Algorithmus auf AES/CBC/NoPadding setze bekomme ich "error" String als Ausgabe. Was ist das Problem?Verschlüsselung ohne Padding funktioniert nicht
Klasse enthält, Verschlüsseln und Entschlüsseln von Funktionen:
public class CriptographyUtils
{
private static final String INIT_VECTOR = "fedcba";
private static final String ALGORITHM = "AES/CBC/NoPadding";
public static String aesEncrypt(String key, String text) // encrypts text (get bytes -> encrypt -> encode -> to String)
{
String result;
try
{
IvParameterSpec iv = new IvParameterSpec(INIT_VECTOR.getBytes());
SecretKeySpec myKey = new SecretKeySpec(fixKey(key).getBytes("UTF-8"), "AES");
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, myKey, iv);
byte[] encryptedBytes = cipher.doFinal(text.getBytes("UTF-8"));
result = Base64.encodeToString(encryptedBytes, Base64.DEFAULT);
}
catch (Exception ex)
{
ex.printStackTrace();
result = "error";
}
return result;
}
public static String aesDecrypt(String key, String text) // decrypts text (get bytes -> decode -> decrypt -> to String)
{
String result;
try
{
IvParameterSpec iv = new IvParameterSpec(INIT_VECTOR.getBytes("UTF-8"));
SecretKeySpec myKey = new SecretKeySpec(fixKey(key).getBytes("UTF-8"), "AES"); // create new KEY in utf-8
Cipher cipher = Cipher.getInstance(ALGORITHM); // create new cipher
cipher.init(Cipher.DECRYPT_MODE, myKey, iv); // set cipher into decrypt mode using my KEY
byte[] decryptedBytes = cipher.doFinal(Base64.decode(text, Base64.DEFAULT)); // get bytes -> decode -> decrypt
result = new String(decryptedBytes); // convert decrypted text to String
}
catch (Exception ex)
{
ex.printStackTrace();
result = "error";
}
return result;
}
private static String fixKey(String key)
{
if (key.length() < 16) // less than 128 bits
{
int numPad = 16 - key.length();
for (int i = 0; i < numPad; i++)
key += "0"; //0 pad to len 16 bytes
}
else if (key.length() > 16)
key = key.substring(0, 16); //truncate to 16 bytes
return key;
}
}
Usage:
verschlüsselnde:
CriptographyUtils.aesEncrypt(key, textToEncrypt)
Decrypting:
CriptographyUtils.aesDecrypt(key, textToDecrypt));
Der Schlüssel ist:
private static final String key = "1234123412341234";