AnonTwi is an open source project to encrypt Twitter and Identi.ca public and private messages hiding the poster’s computer IP. The program interacts with Twitter API using SSL, which stops ISP eavesdropping for certain keywords, connection to Twitter servers can be anonymised with a socks or tor proxy and sending random HTTP header values. Long messages that do not fit in a single Tweet will be split, decryption of URLs and raw data is automatic for anyone using AnonTwi client, messages can be stored in your hard drive, even if Twitter deletes the account you would still be able to read the messages.
Encryption is performed with AES and SHA1, meant to be uncrackable if implemented correctly, since AnonTwi source code is available for download it can be checked for hidden backdoors and coding quality.
Other privacy options include the possibility of sending fake GPS geolocation to appear that you tweeting from a different country, the client can be instructed to insert a random GPS value with each tweet, another choice called “suicide” will attempt to delete all of your tweets, private messages and close your account. AnonTwi supports UTF-8 and Unicode characters to write in Arabic or Chinese and post symbols with detailed colourful outputs, it works in Windows, Mac OS and Linux. Originally released as a command line only tool, it now has an interface that goes with it. You will need to get a Twitter API before you can use AnonTwi, this is not difficult, anyone can open a Twitter developers account and retrieve the API tokens with tor.
Normally you would want as many people as possible to read your Twitter messages, it is probably best to use this tool to simply hide your computer IP when posting public Tweets and keep the encrypted option for private messages only. The other part will need to know a previously agreed password before he can read encrypted communication.