If you are looking for an app that will protect the SMS messages that you send and receive from a particular person on your Android phone, SecurSend Lite is your best bet. This helps you encrypt messages you send and decrypt the messages you receive, using a password.
This app is free on the Android Market and requires Android 1.6 or up. The paid version is also available on the Android Market; it offers a stenography feature, wherein the actual message is hidden by a picture, and can be read by the recipient only by entering a password.
If you want a SMS message you are sending to someone to be encrypted you need to set a password before sending the message. Then tell the recipient the password so that they can decrypt the message. The same applies to the messages you receive from the chosen contact.
SecurSend is a useful app when you want to keep your SMS private. I only wish the app protected emails too.
Disclaimer: *Shanzai.com is a news and reviews website, we do not promote specifically the purchase or sale of the products and services mentioned in our content.