Fortress SMS v1.20 User Guide (Series 60 Text Version) Introduction NOTE THAT THE TRIAL VERSION IS LIMITED TO 3 CHARACTERS FOR THE PASSWORD ON OUTGOING SMS MESSAGES BUT CAN DECODE AND READ MESSAGES FROM THE FULL OR TRIAL VERSIONS PROVIDED THAT THE PASSWORD IS KNOWN. Fortress SMS is a phone based application to send and read encrypted SMS text messages. The messages are encrypted prior to transmission and can only be read by the intended recipient on entry of the correct password. Note that comments addressing phone hardware (such as specific buttons) refer to the Nokia 7650 unless otherwise specified. Whilst every effort has been made to ensure the accuracy of content no liability can be accepted by the author or Silicon Village for errors which may have occurred. Some links in this document access internet sites for which the neither the author nor Silicon Village is responsible. Installation For the Nokia 7650/3650 make sure you have Nokia PC Suite for your phone loaded on you computer, for other Series 60 phones refer to your User Manual. Double click on "fortresssms.SIS" to start the installer (alternatively, for the Nokia 7650/3650 you can start the installer from the relevant PC Suite application). Follow the on-screen instructions. Alternatively you can send the "fortressSMS.SIS" file to your phone via a standard data transfer protocol such as infrared link, bluetooth or email attachment. Then install the file on your phone by using the on-phone installer and following the on-screen instructions. See your User Guide for more details. Sending an Encrypted SMS When you start Fortress SMS you will automatically be in Send mode. To enter Send mode from Read mode select Send Mode from the Options menu. You will see the Enter Message screen. Type in your message and then select Next from the Options menu. This will take you to the Password screen. Enter the password (maximum 16 characters) and select Next to prepare the message for sending. You will then see your phones standard SMS editor with the encrypted message loaded. Select the recipient(s) and send the message in the normal manner. (Note that you may also abort the message, or save the message in the Drafts folder in exactly the same way as with a normal SMS message). Note that you should not insert or add any additional text or graphics as these will not be encrypted and may prevent the message being read by the receiver. When you have sent (or otherwise processed) the message you will see the Message Processed screen. To send another message select Next. Reading an Encrypted Message To enter read mode from send mode, select Read Mode from the Options menu. You will see a screen similar to this one. The messages are listed with the most recent one first. You may view either the Inbox (default) or the Sent Items folder by selecting the appropriate option from the Select Folder... sub-menu. The default view is sender but this can be changed to date/time by pressing the Joystick button. Select the message and select Next to enter the password screen. Enter the password and select Next. The OK after Decoded Text. indicates that the text has not been damaged or altered (checked using an MD5 message digest of the original text sent with the message). Entering the wrong password will display garbage text with Fail being indicated. To delete the current message press the clear key while viewing the message. General If the phone rings (or an outgoing call is started) whilst using Fortress SMS the application will be switched to the background while the phone call is in progress. Note that because the phones standard SMS editor is used to send encrypted messages, if you are using it to send a message when the phone rings you will need to use the menu button to return to Fortress SMS once the message has been sent (alternatively you can click on the Fortress SMS icon). For convenience message text and password information are retained until overwritten during Send or Read sessions. This information is cleared by toggling between Send and Read modes. To maximize security you are advised to quit Fortress SMS when you have finished using it. Fortress SMS supports Unicode character sets by taking the code page indication byte of the first entered character and applying this to all subsequent text. This means only one character set can be supported for each sent message. Note also that the relevant character set must be supported on both the senders and receivers phone for the message to be read. Features * Advanced Encryption Standard compliant. * Phone to phone SMS message encryption that is service independent. * Phone based application, compose, send and read on the phone. * Messages stored encrypted. * Supports long (concatenated) messages (up to 304 characters of plain text). * Supports multiple recipients. * MD5 based integrity checking of the encrypted message. * Supports Unicode character sets. * Simple and easy to use - simply compose the message, enter a password and send. To read simply select the message, enter the correct password and read. Technical * Platform. Series 60 (Symbian v6.1 / 7.0s) - for example the Nokia 7650 * Encryption Algorithm. Rijndael (128 bit key, 128 bit block) with cipher block chaining (Advanced Encryption Standard compliant). * Hash Algorithm. MD5 Acknowledgements Rijndael is a strong block cipher developed by Joan Daemen and Vincent Rijmen and is the chosen cipher for the U.S. Advanced Encryption Standard (AES). This program uses an independent implementation of the algorithm based on original code developed by Dr Brian Gladman. The mode offered by Fortress SMS is a 128 bit key size for 128 bit blocks with cipher block chaining (CBC). This mode is compatible with the AES. Fortress SMS is a trademark of Silicon Village. MD5 is a registered trademark of RSA Data Security, Inc. Other product or company names may be trademarks of their respective owners. Website. www.fortressmail.net Email. sales@fortressmail.net User Guide v1.2 - Last updated Wednesday, 24 December 2003