I need to write Java code for encrypting a string using AES (Rijndael).
There is an already working C# code that does this same encryption for the same purpose.
The C# code:
RijndaelManaged rijndaelCipher = new RijndaelManaged();
rijndaelCipher.KeySize = 256;
rijndaelCipher.BlockSize = 256;
rijndaelCipher.Mode = CipherMode.CBC;
rijndaelCipher.Padding = PaddingMode.PKCS7;
byte[] pwdBytes = System.Text.Encoding.UTF8.GetBytes(password); // password is 32 bytes long
byte[] keyBytes = new byte[32];
System.Array.Copy(pwdBytes, keyBytes, 32);
rijndaelCipher.Key = keyBytes;
rijndaelCipher.IV = keyBytes;
ICryptoTransform transform = rijndaelCipher.CreateEncryptor();
The Java code I came up with:
byte[] sessionKey = SENDER_KEY.getBytes(StandardCharsets.UTF_8);
byte[] iv = SENDER_KEY.getBytes(StandardCharsets.UTF_8) ;
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
SecretKeySpec secretKeySpec = new SecretKeySpec(sessionKey, "AES");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
byte[] cipheredText = cipher.doFinal(stringedXmlForSending.getBytes());
When I execute the Java code I get the exception: java.security.InvalidAlgorithmParameterException: Wrong IV length: must be 16 bytes long
Is it true that I cannot write in Java Rijndael encryption which is using 32 bytes keys?
Another difference is that padding in the C# is PKCS7 while in Java there is PKCS5. Will it still work?
The basic Java Cryptographic Extensions only provide AES implementations which is compatible with Rijndael at 128-bit block size. You should use 128-bit BlockSize so that you are compatible with most implementations which implement AES. If you do then the padding is no problem, since PKCS#5 is the same as PKCS#7 padding in AES.
It's important to note that AES is standardized which Rijndael isn't.