how to:How to Send and Receive Secure Text Messages with CryptoSMS
If you are using SMS to communicate between campaign leaders, organize a protest, or share information, you may be worried about how secure that text is. Can someone else view it? Can someone else try to access your texts? There are a few different products out there that can help you better protect your texts. These systems worked by encrypting your text messages.
This how to guide will look at how you can send and receive SMS more securely using CryptoSMS. See our other guide for more general information about using mobile phones for activism.
SMS you have sent or received are stored on your mobile phone’s SIM card. Standard SMS include your location, phone, and SIM card identifiers. This information is visible to network operators. In certain locations, your text messages could be monitored. For example, in China, there are nearly 3,000 SMS surveillance centers to monitor the content of text messages being sent and received.
SMS encryption services work by asking the SMS sender to choose a key (or password) which is used to encrypt the message. The sender must disclose the key to the intended recipient. The recipient then uses the key to decrypt the message. Public keys are another form of encryption that is even more secure. This form uses two different keys.
Cryptosms sends and receives encrypted texts and public keys. It only works on Java-enabled phones. The program is free; you don’t need to buy a license to use it. The latest version of the software was released in June 2009. Remember: CryptoSMS is not an anonymizer and does not hide your phone id or number.
Make sure your mobile phone meets the prerequisites of CryptoSMS. Check their list of known devices that are compatible here. You will also need 144kB of free space on your phone to install the program.
To download CryptoSMS, go to http://cryptosms.org/
Click on “Download” to be directed to the website where you can download the software.
Click on “Documentation” to download the installation guide and user guide.
There are two options for installing CryptoSMS onto your mobile phone: either downloading it via your computer or downloading it directly to your phone.
Download CryptoSMS via your desktop PC or laptop if you have mobile phone management software on your computer, such as the Nokia PC Suite. Point your browser to www.cryptosms.org/ota. Download the file called ‘CryptoSMS.jar’ to your desktop or another folder.
Start your mobile phone management software and connect your mobile phone to your computer. In the management software, choose ‘Install Application.’ Locate the CryptoSMS file you downloaded to your computer and transfer the file to your phone.
Once you see the file ‘CryptoSMS.jar’ in the program folder of your mobile phone, it is installed.
Alternatively, you can download CryptoSMS directly to your phone if you have the capability to browse the internet from your mobile device.
Start your mobile web browser and connect to www.cryptosms.org/ota/
Download the file ‘cryptosms.jad’
You may be prompted by your mobile phone asking if it is okay to install CryptoSMS on your mobile. Say Yes or OK. Your phone will then begin to download the program. The application will be automatically installed on your phone.
Where is the application installed? This depends on the type of phone you have. It could be under games, tools, or programs.
The first time you use CryptoSMS, you will see the initialization screen. You will be prompted to enter your mobile phone number, a name, and a passphrase. You only have to go through this process once. Each subsequent time you use CryptoSMS, you will only need to enter your passphrase.
To write a text message: On the main menu, enter the menu entry “Write SMS” by pressing the OK or Enter button on your phone. You will then see a text input box. You will have 100 characters to type your message.
After you finish typing your SMS, press OK. On the next screen, select the recipient.
Add a New Entry to add an entry to your address book.
Once you have chosen the recipient, CryptoSMS starts the encryption process of the SMS. A confirmation screen will appear once the message is sent.
You can only send encrypted messages if you have the recipient’s key!
To receive a text message: When you are sent an encrypted SMS, it will not appear in your plaintext SMS inbox. You will get a short notice on your mobile’s display screen that there is a new message and to start CryptoSMS.
New messages are found in the New Messages folder of CryptoSMS’s main menu. You can view the message, delete it, or view more details about the message.
If you choose to view the message, decryption starts. Once the decryption is finished, you will see the contents of the SMS.
After you read the message, it will be moved into the Old Messages folder.
To receive a key: On the main menu, you will see the entry “Received Keys.” This folder holds a list of all public keys other people have sent to you. You can only read an encrypted message if you have the recipient’s key.
Managing your Addressbook: When you open your addressbook for the first time, it will not contain any entries.
To add an entry, enter New Entry and type in the name and number. Then press OK.
Select Edit Entry to edit an existing entry.
Select Send Pubkey to send your public key to any entry in your addressbook. Remember, you have to exchange keys if you want the other person to be able to read encrypted messages from you!
Other popular systems used to encrypt text messages are SMS 007 and Kryptext. Both must be purchased.
SMS007 uses password encryption, and also anonymises the sender and receiver by created an encrypted contact list. The company behind SMS007 in Czech Republic. You have to buy a license to use the service and it costs 35 euro (39 USD).
Kryptext is another system that works on java-enabled phones from a UK-based company. It is offered in the UK for 49 pounds per license.