The present invention exists in the construction, arrangement, and combination of the various parts of the device, and steps of the method, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:
As noted above, current state-of-the-art does not secure a normal voice call in manners contemplated by the presently described embodiments. The typical voice call may be tapped into by unauthorized parties.
However, according to the presently described embodiments, a voice call can be conducted using suitable security protocols that are configurable by the users and transparent to the network. Thus, the network will be able to pass the call through, but no unauthorized party on the network will be able to understand the content of the call.
In one form, the calling party and called party indicate to each other that they will engage in a secure voice communication session. Then, each party presses a special button (either a hardware or software type button) that will trigger appropriate switches (e.g. an originating mobile switching center and a terminating mobile switching center) to bypass, or disable, its conventional vocoder functions. As a result, only vocoders implemented on the mobile device will be activated and remain in the speech path. The vocoders within the mobile device not only code and decode messages but also encrypt the transmission so that no other party in the network can listen to the conversation. After completion of the secure voice communication session, the network vocoding functions are restored.
Referring now to the drawings wherein the showings are for purposes of illustrating the exemplary embodiments only and not for purposes of limiting the claimed subject matter,
More specifically, with reference now to
The vocoder 300 is operative, under control of the software control portion 302, to selectively code, decode, encrypt and decrypt messages during the secure voice communication session. Vocoding may be accomplished using a variety of different vocoding techniques and/or vocoders. For example, a CDMA vocoder may be used. Alternatively, an 8K vocoder, a 13K vocoder, an EVRC (Enhanced Variable Rate Coding) vocoder, or an SMV (Selectable Mode Vocoding) vocoder may be used. As still further alternatives, a QCELP—Qualcomm Code Excited Linear Prediction vocoder, an ACELP—Adaptive Code Excited Linear Prediction vocoder or an ADPCM—Adaptive Differential Pulse Code Modulation vocoder may be used.
Encryption may be accomplished using any of a variety of encryption techniques. For example, the following techniques will suffice.
RSA: RSA is a public-key cipher developed by (and named after) Ron Rivest, Adi Shamir, and Leonard Adleman, in the late 1970's. RSA is the “standard” public-key encryption algorithm. RSA is a variable-length key. Common key lengths are 256, 512, 768, 1024 and 2048.
Blowfish: Blowfish is a block cipher algorithm developed by Bruce Schneider. Blowfish is a variable-length key algorithm. The most common key lengths are 128-bit and 160-bit. Blowfish can be used domestically but cannot be exported.
CAST: Cast is a 64-bit symmetric block cipher developed by C. M. Adams and S. E. Tavares. CAST is similar to DES but is a proprietary encryption system. MS Exchange uses CAST for symmetric key encryption.
DES: DES is a block cipher algorithm developed by the National Institute of Standards and Technology (NIST) Data Encryption Standard. DES has a fixed key length of 56 bits. DES cannot be exported.
IDEA (International Data Encryption Algorithm): IDEA is a 128-bit block cipher developed by James Massey and Xuella Lai in 1990. Encryption products developed in the US that use IDEA encryption cannot be exported, but IDEA was developed in Zurich and is commonly used in Europe.
RC2: RC2 is a block cipher algorithm developed by RSA Data Security, Inc. The key-length is variable but typically limited to 40 bits so that RC2 can be used for both domestic and international encryption. RC2 is a commonly-used international encryption algorithm.
RC4: RC4 is a stream cipher developed by RSA Data Security, Inc. The key-length is variable but typically limited to 40 bits so that RC4 can be used both for domestic and international encryption. A 40-bit version of RC4 is used by MS Office 97 for data encryption. A domestic, 128-bit version of RC4 is available for domestic encryption.
Skipjack: Skipjack is a symmetric block cipher used by the Clipper and Capstone chips. Skipjack has a fixed key length of 80 bits.
Triple DES: Triple DES is a version of DES that encrypts a message or file three times using the DES 56-bit key. A plain text message or file is encrypted using DES. The encrypted message is again encrypted using DES, and the twice-encrypted message is encrypted a third time using DES.
The voice security activation module 304 is operative to selectively initiate a secure voice communication session for the first mobile device by transmitting a message to the network. In one form, the message, e.g. a special message, includes a service option request field populated with a unique identifier indicating to the network that a secure voice communication session is being initiated.
The interface module 306 may take a variety of forms. In one form, it is operative to transmit and receive messages necessary for communication according to the presently described embodiments. For example, it is operative to transmit the special messages contemplated above.
It should be understood that the described switching element, e.g. the mobile switching center, may also provide a variety of other functions to the network not described herein for the sake of brevity. It should also be understood that, in lieu of a mobile switching center, other types of switching elements may be provided with the functionality of the presently described embodiments. These types of alternatives may be dependent on the design of the network and/or the technological generation of the network.
With reference now to
Of course, in the forms described above, the software is at least partially centralized. However, it should be understood, that the software may also be distributed in a variety of suitable manners within the network.
With reference back now to
It should be understood that the mobile device 104 is also typically activated into the voice security mode so that transmission can occur.
Once the mobile devices are in the voice security mode, each mobile device will determine whether it is sending or receiving the transmission (at 504). In this regard, the mobile devices will simply wait to either receive a transmission or wait for the user to speak to send the transmission.
If the mobile device is sending a voice transmission, appropriate vocoding functions are performed (at 506). Next, the transmission is encrypted (at 508).
Once encrypted, the message(s) are then transmitted (at 510). If the communication is to remain in a secure mode, the device simply waits to send or receive the voice transmission. If, however, secure voice communication is abandoned, the routine is ended (at 514).
Likewise, if the mobile device is to receive voice transmissions, the transmission is received (at 516). The data is then decrypted (at 518). Techniques noted above may be used in the decryption process. Next, vocoding functions are performed on the data. (at 520). Again, vocoding techniques contemplated above may be used to decode. At this point, the user who receives the voice transmission can listen and understand the transmission. If the mobile unit is to remain in the secure mode (at 522), it simply awaits further transmissions or the sending of further transmissions. If the secure mode is to be discontinued, the routine is simply ended (at 524).
With reference now to
The above description merely provides a disclosure of particular embodiments of the invention and is not intended for the purposes of limiting the same thereto. As such, the invention is not limited to only the above-described embodiments. Rather, it is recognized that one skilled in the art could conceive alternative embodiments that fall within the scope of the invention.