DEVICE AND METHOD FOR TRANSMITTING AND RECEIVING CODIFIED SMS MESSAGES

The present invention relates to a device for transmitting and receiving SMS (Short Message Service) messages, for example a cellular or cordless telephone. The present invention relates also to a process which can be carried out by said device.

Known digital devices transmit and/or receive SMS messages containing only alphanumeric characters, since the SMS protocol only allows to send strings of characters. If it is desired to codify an SMS message, the known devices can only transform the characters of the SMS message into other alphanumeric characters according to more or less complex encryption algorithms.

However, when the SMS message is decrypted by the receiving device, it can be read not only by the receiver, but also by anyone who can access the display of the device. It is therefore an object of the present invention to provide a device which allows to make readable only by the receiver the SMS messages, even if decrypted. Said object is achieved with a device, as well as with transmission and reception processes, whose main features are disclosed in claims 1, 15 and 17, respectively, while other features are disclosed in the remaining claims. Thanks to the use of graphic symbols automatically generated by the device by means of particular digital tables, the device and the process according to the present invention allow to convert a standard SMS message into a more or less complex graphic message which can be interpreted by the receiver without a further decryption thereof, which is in any case possible thanks to the distribution of the digital tables among the potential users.

Furthermore, the SMS message can be in any case easily encrypted by means of alphanumeric characters stored in the same tables, so that it cannot be understood even it is intercepted illegally.

According to a particular aspect of the invention, groups of letters of the word composing the SMS message can be converted into complex graphic symbols, so as to reduce the size of the SMS message on the display of the digital device and to increase

the encryption level without compromising its intelligibility.

According to another particular aspect of the invention, the graphic symbols can be associated to sounds, so as to obtain an encryption not only graphic but also acoustic. Further advantages and features of the device and the process according to the present invention will become clear to those skilled in the art from the following detailed and non-limiting description of an embodiment thereof with reference to the attached drawings, wherein:

- figure 1 shows a front view of the device; - figures 2 and 3 show tables stored in the device of figure 1 ; and

— figure 4 shows a step of the process.

Referring to figure 1, it is seen that the system according to the present invention comprises in a known way at least one digital device 1, for example a cellular telephone, suitable for transmitting and/or receiving SMS messages. The digital device 1 comprises a keyboard 2 provided with a plurality of keys 3 and at least one display 4 for displaying a plurality of first alphanumeric characters 5 which can be input into the digital device by pressing keys 3 one or more times for composing an SMS message to be transmitted. Display 4 can also display an SMS message received by device 1. Alphanumeric characters 6 are printed on keys 3 or close to them for simplifying the input of the first alphanumeric characters 5 into the digital device 1.

Referring also to figures 2 and 3, it is seen, that, according to the invention, the digital device 1 comprises also a non-volatile memory containing one or more digital tables 7, 8 in which the first alphanumeric characters 5 are associated to one or more graphic symbols 9 and/or to one or more second alphanumeric characters 10. The graphic symbols 9 have shapes and/or colors different from each other. A default table 7 can for example associate the first alphanumeric characters 5 to a first set of default graphic symbols 9 and to second alphanumeric characters 10 same as the first ones. The default table 7 also includes a code 11 indicating key 3 associated to the first alphanumeric characters 5. The graphic symbols 9 can be printed on keys 3 or close to them, in particular on a mask covering keyboard 2. Therefore, the user, by pressing keys 3, can input into the digital device 1 the graphic symbols 9 associated to keys 3 in table

7 and display them on display 4.

The default table 7 can be modified by the user by means of a software installed in the digital device 1 for creating a user table 8 in which the first alphanumeric characters 5 are associated to one or more graphic symbols 9 and/or to one or more second alphanumeric characters 10 and/or to a code 11 indicating a key 3, wherein at least one of these associations is different with respect to the default table 7. The user table 8 can be contained in a digital file and transmitted in a known way by the digital device 1 to one or more other digital devices, for example through an infrared port, an external nonvolatile memory or a radio transmission. The graphic symbols 9 can be printed on keys 3 or close to them, in particular on a mask covering keyboard 2, according to the associations created in the user table 8. A software installed in the digital device 1 can also allow to modify the shape and/or the colors of the graphic symbols 9 in the user table 8.

When the user composes an SMS message, idisplay 4 shows the first alphanumeric characters 5 of the SMS message and/or a series of graphic symbols 9 associated to the first alphanumeric characters 5 in the digital table 7 or 8 (in figure 1 the association of the default table 7 is used). When the user sends the SMS message, this message contains the first alphanumeric characters 5 of the message, or a software installed in the digital device 1 translates the first alphanumeric characters 5 into the second alphanumeric characters 10 according to the digital table 7 or 8, so that the SMS message contains an encrypted string of characters.

When the SMS message is received by another digital device comprising a digital table, in particular the same digital table 7 or 8, the display of this other device shows the first alphanumeric characters of the SMS message received and/or the graphic symbols associated to the first alphanumeric characters in the digital table. A software installed in this other digital device retranslates the second alphanumeric characters into the first alphanumeric characters according the mutual association of the relevant digital table if the digital device of the sender carried out said translation.

' Referring to figure 4, it is seen that two or more graphic symbols 9 corresponding to a portion of the SMS message can be converted into a complex graphic symbol 12. Said conversion is automatically carried out by a software installed in the digital device

- A -

1 according to the shapes and/or the colors of the graphic symbols 9. In particular, the complex graphic symbol 12 comprises at least a portion of two consecutive graphic symbols 9 of the SMS message, wherein the portion of the first graphic symbol 9 is bigger than the portion of the second graphic symbol 9. Said two graphic symbols 9 preferably correspond to a vowel and to a consonant, or vice versa, of a word of the SMS message. For example, the dark waning half moon and the light circle of figure 4 are combined so as to form a complex graphic symbol comprising the same dark waning half moon partially covered by the same light circle made smaller. The subsequent two waxing half moons of figure 4 are combined so as to from a complex graphic symbol comprising the dark waxing half moon and a smaller conventional symbol, for example a rhomb, of the same color of the second waxing half moon. Said conventional symbol represents a double of the graphic symbol to be converted.

The graphic symbols 9 can be also associated to digital sounds in digital tables 7 or 8, for example each key 3 or first alphanumeric character 5 can be associated to a note, in which case the corresponding graphic symbol 9 can represent said note on display 4. Keys 3 may have different shapes and positions on keyboard 2 and can be also provided with micro-displays for showing different alphanumeric characters 5 and/or graphic symbols 9 associated to them in the digital tables 7 or 8.

Possible modifications and/or additions may be made by those skilled in the art to the hereinabove described and illustrated embodiment of the invention while remaining within the scope of the following claims.