You can use the freeware Multiobfuscator to encrypt text messages. It can be downloaded here: http://embeddedsw.net/MultiObfuscator_Cryptography_Home.html
The tool can require three passwords to decrypt the message you want to send.
You enter the message in a blue notepad in the program:
Clicking Lock! will generate a long encrypted text code.
You can then send this code in a message to someone else who will be able to decode it with Multi-Obfuscator, who has separately received the passwords.