SMS Privacy - Encrypt your SMS messages.

SMS Privacy lets you lock your SMS messages by encrypting them using the AES256 standard, giving you the confidentiality you need.

You can choose which message to "lock" and leave visible un-encrypted. Also, please be aware that only the text is encrypted. Message attachments are left as is. Perhaps that will come in future updates.

EDIT: Some people(mostly Russians) think this was a stolen idea. I don't know who and where I stole it from. But if you think I did, just do yourself and me a favor, get out of here and download the one you think is the original app. Don't leave negative reviews just because you woke up on the wrong side of bed. Thank you in advance.