This app sends normal SMS messages but with contents encrypted. So no
SSL/TLS needed really.
You may ask how I encrypt them. No secrets. I am using the Bouncy
Castle light weight cryptographic API available here http://www.bouncycastle.org/
. The encryption algorithm I use is Advanced Encryption Standard
(AES), and where I need secure hashes I use SHA-256 digests.
I hope that sheds some light.