I am running kamailio-5.3.4 on one of my setup and I intend to use the crypto module in the same. 

I wanted to understand the following details when the module is used:

I understand it uses the AES algorithm, is that correct?

Does it use AES 128, 192 or 256 bit algorithms?

Does it use CBC or ECB mode for AES?

The 5.3 version does not have an parameter for init-vector, so does kamailio use any init vector internally in this case?

When i compared the encrypted text that kamailio produces and the ones available online, they were producing different outputs even when same shared secret was used. Hence asking for more clarification

PS: Upgrading kamailio is my very last option as this is one af an old setup which only needs this feature without much changes.

Thanks for any valuable response.