The present invention relates to the field of wireless communication devices. More specifically, the invention relates to wireless communication device accessories and related methods of use.
Various peripheral devices, generally referred herein to as “accessories,” may be attached and detached from mobile phones, and other wireless communication devices. These accessories, when attached, provide additional functionality and/or otherwise enhance the performance of the phone. In other cases, accessories facilitate the user's ability to productively or comfortably use the mobile phone. A phone battery, though normally thought of as integral with a phone, is also considered an “accessory” for purposes of the present disclosure.
During the design and development of wireless communication devices, it is common to test the compatibility and/or reliability of accessories anticipated for use with the wireless communication device. Such testing ensures that an accessory will operate with a reasonable level of compatibility with the wireless communication device. Unfortunately, accessories made available by third parties for use with wireless communication devices are often not tested or, even if tested, fall below the standards defined by manufacturers of wireless communication devices and/or other standards, e.g., defined by government bodies. Such accessories (referred to herein as “unauthorized accessories”) have the capability of damaging the wireless communication device and/or pose a safety threat to a consumer.
Existing techniques for preventing unauthorized accessories to be employed with wireless communication devices have been relatively easy to circumvent. For example, connectors employing unique mechanical keying arrangements can be overcome with mechanical modifications to the connectors. Electrical arrangements employing resistors for authentication are likewise easily circumvented with appropriate circuitry. Finally, digital communication techniques employing fixed passwords or rolling codes are relatively easy to defeat or mimic.
Accordingly, there remains a strong need in the art for an effective and secure authentication method and apparatus for wireless communication devices.
A method and apparatus for authenticating a mobile phone accessory is disclosed. According to one embodiment, the mobile phone and the accessory are capable of being coupled for communication over a first line via an interface.
In an exemplary embodiment, the mobile phone computes a challenge communication, such as a random number or pseudo random number, and transmits the challenge communication over the first line to the accessory. In response, the accessory receives the challenge communication over the first line, and computes a response communication based on the challenge communication, a hash algorithm and an electronic key. The response communication is transmitted over the first line to the mobile phone. In some embodiments, the accessory also optionally enables the phone accessory for use with the mobile phone, such as by making the requisite electrical connections, for example.
The response communication generated by the accessory is received by the mobile phone over the first line. The mobile phone computes a validation result based on the challenge communication, a hash algorithm and an electronic key. The mobile phone compares the response communication with the validation result, and enables the phone accessory for use with the mobile phone based on the comparison of the response communication with the validation result. In the case where the accessory is authorized for use with the mobile phone, the response communication generated by the accessory will match the validation result, and the accessory is enabled for use with the mobile phone. Otherwise, the accessory is not enabled for use with the mobile phone.
As discussed below, the particular mobile phone accessory authentication arrangement and technique disclosed herein result in significantly improved security, thereby significantly reducing the misuse of unauthorized accessories with mobile phones.
Other features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art after reviewing the following detailed description and accompanying drawings.
Referring first to
Although not shown in
Mobile phone 100 further includes a number of input/output (“I/O”) devices for receiving and transmitting information to the user. For example, mobile phone 100 includes display 106, keys 108 and 110, microphone 112 and speaker 114, each typically coupled to the processor via an appropriate I/O interface.
Continuing with
Referring now to
As shown in
According to another embodiment, signaling lines 228 and 234 may be omitted, and, thus, communication as described herein over lines 228 and 234 may be carried out over supply voltage lines 226 and 232, respectively. For example, bi-directional signaling may be employed over lines 226 and 232 via modulation over lines 226 and 232. As another example, bi-directional signaling may be employed over lines 226 and 232 by employing switches to enable lines 226 and 232 to operate in a first bi-directional signaling mode during the authentication process and to enable lines 226 and 232 to operate in a second voltage supplying mode after accessory 202 is authenticated. A benefit of enabling communication over existing supply voltage lines 226 and 232 is that dedicated communication lines 228 and 234 is not required, and thus, the interface and connectors between the mobile phone 200 and accessory 202 need not be modified from previous arrangements that do not employ the authentication method described herein.
Continuing with
According to one embodiment, the method of flow chart 300 is initiated when an accessory is connected to a mobile phone, e.g., when accessory 202 in
At block 304, the challenge communication is transmitted from the mobile phone to the accessory for processing. For example, in
At block 306, processor 222 of mobile phone 200 computes a first hash value (“Hash 1”) based on the challenge communication generated during block 302. Hash 1 may be generated by a first hash algorithm employing a first electronic key, and further using the challenge communication as its input data. For example, the first hash algorithm may be a one-way hash algorithm. In general, for every unique input string, a different output string is produced. For purposes of the present disclosure, Hash 1 is referred to as a validation result, which is used to compare against a response communication generated by an accessory for authenticating the accessory, as discussed below.
At block 308, processor 224 of accessory 202 receives the challenge communication transmitted during block 304 and computes a second hash value (“Hash 2”) based on the received challenge communication. Hash 2 is also known as a response communication, since Hash 2 is generated in response to the received challenge communication. Like Hash 1, Hash 2 may be generated by a second hash algorithm employing a second electronic key, and further using the challenge communication as its input data. In a case where accessory 202 is authorized for use with mobile phone 200, the second hash algorithm and/or the second electronic key would be supplied to the manufacturer of accessory 202 for storage in a memory used by processor 224 during the authentication process. As such, Hash 2, generated by the second hash algorithm and the second electronic key, can be authenticated by mobile phone 200, as discussed below. Unauthorized accessories, lacking either the second hash algorithm or the second electronic key would fail to generate the requisite Hash 2 for proper authentication, also discussed below.
At block 309, Hash 2 is transmitted by the mobile accessory to the mobile phone for processing. For example, in
At decision block 311, a determination is made as to whether processor 222 has or has not received a response communication (Hash 2) from accessory 202. By way of illustration, Processor 222 will not receive a response communication where accessory 202 is not configured to transmit the response communication in response to the challenge communication transmitted during block 304. In such case, accessory 202 is considered unauthorized, and mobile phone 200 disables accessory 202 from operating with mobile phone 200 at step 318, as discussed below. If a response communication is received, method 300 continues to decision block 312.
At decision block 312, processor 222 has received the response communication (Hash 2) from processor 224 and compares Hash 1 generated during block 306 with Hash 2 received from accessory 202. In the case where accessory 202 is an authorized accessory, Hash 1 will match Hash 2, in which case processor 222 enables accessory 202 for operation with mobile phone 200 at step 314. As discussed above, upon validating accessory 202, mobile phone 200 may allow certain portions of mobile phone 200 to communicate with or otherwise utilize accessory 202. Mobile phone 20 may command the accessory to change its configuration or connection (represented by block 310) or may cause the configuration to occur in mobile phone 20 (represented by block 314 as discussed below). By way of illustration, enabling accessory 202 may involve, among other things, providing the requisite electrical connections, e.g., via lines 226 and 230 to mobile phone components of mobile phone 200. Accessory 202 is thereby authenticated and is enabled for use with mobile phone 200. In the case where accessory 202 is not an authorized accessory, Hash 1 will not match Hash 2, in which case processor 222 disables accessory 202 from operating with mobile phone 200 at step 318. For example, disabling accessory 202 can be carried out by preventing line 226 and/or line 230 of accessory interface 216 from connecting to respective mobile phone components of mobile phone 200.
When an accessory is disabled, a message may be communicated to the user, e.g., via a display message or audible message, to indicate that the accessory is not compatible with the mobile phone. Other appropriate messages may further include a warning that the accessory may damage the mobile phone.
Due to the particular arrangement and operation of mobile phone 200 and accessory 202, authentication of accessories for use with mobile phone 200 is significantly improved. For example, the hashing functions and the challenge and response technique employed in method 300 are extremely difficult and expensive to analyze and undermine. As a result, the ability for an unauthorized manufacturer of accessories to bypass the authentication arrangement of mobile phone 200 is significantly reduced. Benefits are realized by manufacturers of mobile phone 202, since use of unauthorized accessories which may damage mobile phone 202 is significantly reduced. In addition, users of the mobile phone 202 are benefited since the reduced likelihood for damage will result in reducing the loss of usage of the mobile phone during the repair period.
According to another embodiment of the invention, the processes associated with blocks 302 and 306 of method 300 depicted in
From the above description of exemplary embodiments of the invention, it is manifest that various techniques can be used for implementing the concepts of the present invention without departing from its scope. Moreover, while the invention has been described with specific reference to certain embodiments, a person of ordinary skill in the art would recognize that changes could be made in form and detail without departing from the spirit and the scope of the invention. The described exemplary embodiments are to be considered in all respects as illustrative and not restrictive. It should also be understood that the invention is not limited to the particular exemplary embodiments described herein, but is capable of many rearrangements, modifications, and substitutions without departing from the scope of the invention.