cryptography - Java default Crypto/AES behavior

Question

Does anyone know what the default Java crypto behavior is for:

SecretKeySpec localSecretKeySpec = new SecretKeySpec(arrayOfByte, "AES");
Cipher localCipher = Cipher.getInstance("AES");

Specifically I am looking to understand how those classes generate the IV, as well as what is the default encryption mode when just specifying "AES". Thanks.

Answer 1

For Oracle JDK 7 (tested), the default cipher for AES is AES/ECB/PKCS5Padding. The Java Security documentation doesn't mention about this though (http://docs.oracle.com/javase/6/docs/technotes/guides/security/StandardNames.html#algspec), have to do some JUnit testing to find out.