Electrical computers and digital processing systems: support – Multiple computer communication using cryptography – Particular communication authentication technique
Reexamination Certificate
1999-04-14
2001-08-07
Swann, Tod (Department: 2132)
Electrical computers and digital processing systems: support
Multiple computer communication using cryptography
Particular communication authentication technique
C713S152000, C380S217000, C380S269000, C380S276000, C380S275000
Reexamination Certificate
active
06272633
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a method and apparatus for processing voice data for transmission and receipt over a network. More particularly, the invention relates to methods and apparatus for processing of secure voice communications for transmission and receipt over a network.
B. Description of the Related Art
The advent of digital networks has expanded the possibilities for the exchange of information. In particular, the speed of communications over these networks has developed dramatically. Most recently, the speed of digital networks has almost doubled every three years. Due to the new capabilities resulting from the improvements in speed, the transmission not only of data but also of voice and multimedia has become feasible. However, the security for these types of communications has not matched the improvements in speed.
Indeed, with the technological sophistication of digital networks, many users have begun to utilize digital networks for voice communications. Of course, as with any form of voice communications, confidentiality is a primary concern. Specifically, because voice communications entail important commercial and governmental information, there is an obvious need for confidentiality and security. In addition, the need for secure voice communications will also include communications over a wire line as well as communications over digital networks. Moreover, as digital networks are used more and more for multimedia applications, the same concerns of confidentiality and security will become relevant outside of the confines of voice communications.
With conventional systems and methods for secure voice communications over wire lines, there are a limited number of types of secure telephone equipment, such as secure telephone unit, 3rd generation (STU-III) equipment and secure terminal equipment (STE). However, STU-III uses obsolete synchronous analog techniques, and STE requires an ISDN connection. For these reasons, these systems are generally considered inadequate for secure voice communications.
With the present systems and methods for secure communications over digital networks, such as, for example, the Internet, neither STU-III nor STE is compatible with Internet-based networks. In fact, the only known means of transmitting and receiving secure voice communications using an Internet protocol is the PGP-Fone. The PGP-Fone is distributed over the Internet and utilizes the PRETTY GOOD PRIVACY (PGP) encryption technique. However, the PGP-Fone does not support narrowband and similar bandwidth-limited connections. In addition, the PGP-Fone is incompatible with government-standardized voice coding and cryptographic techniques, such as mixed excitation linear prediction (MELP) for voice coding and SKIPJACK for encryption. As a result, the PGP-Fone does not entail the technical sophistication necessary for adequate secure voice communications over a digital network, such as the Internet.
Due to the absence of a system or method of transmitting, receiving, and processing voice data in a secure manner over the Internet, there is a general need for such a system and method. In addition, there is also a need for such a secure system and method for the highly important voice communications of business and government, including those that require an Internet connection.
SUMMARY OF THE INVENTION
Methods and apparatus consistent with the present invention overcome the shortcomings of the conventional systems by processing secure voice for transmission and receipt over a network.
In accordance with the purposes of the invention, as embodied and broadly described herein, one aspect of the invention includes a method consistent with the present invention of transmitting sound. This method comprises receiving an analog signal representing sound, converting the analog signal into digital information, translating the digital information into a data frame using a linear prediction technique, encrypting the data frame into a ciphertext frame, forming a secure voice frame from the ciphertext frame, and transmitting the secure voice frame.
In another aspect, the invention includes a method for receiving sound, comprising the steps of receiving a secure voice frame, removing a header from the secure voice frame to obtain a ciphertext frame, decrypting the ciphertext frame into a data frame, translating the data frame into digital information using a linear prediction technique, converting the digital information into an analog signal representing sound, and outputting the sound.
In yet another aspect, the invention includes a method for transmitting and receiving speech, comprising the steps of receiving an analog signal representing speech, converting the analog signal into digital information, translating the digital information into a data frame using a linear prediction technique, storing the data frame in a first transmitter buffer, encrypting the data frame into a ciphertext frame using a codebook encryption algorithm, storing the ciphertext frame in a second transmitter buffer, forming a secure voice frame from the ciphertext frame, transmitting the secure voice frame over a network, receiving the secure voice frame over a network, removing the header from the secure voice frame to obtain the ciphertext frame, storing the ciphertext frame in a first receiver buffer, decrypting the ciphertext frame into a data frame using a codebook decryption algorithm, storing the data frame in a second receiver buffer, translating the data frame into digital information using a linear prediction technique, converting the digital information into an analog signal representing speech, and outputting the speech.
Additional aspects of the invention are disclosed and defined by the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 5526353 (1996-06-01), Henley et al.
patent: 5553063 (1996-09-01), Dickson
patent: 5799088 (1998-08-01), Raike
patent: 5883891 (1999-03-01), Williams et al.
patent: 5974142 (1999-10-01), Heer et al.
PGPfone—Owner's Manual (Philip R. Zimmermann, Jul. 28, 1996, www.pgpi.org/products
ai/pgpfone).*
Department of Defense Voice Processor Consortium Homepage (Sep. 14, 1998, www.plh.af.mil/ddvpc/index.html).*
“Department of Defense Voice Processor Consortium Homepage,” Website at http:/www.plh.af.mil/ddvpc/index.html (Sep. 14, 1998).
Duke Andrew Cameron
Giramma Robert Michael
Tomasetti Ryan Charles
Callahan Paul E.
General Dynamics Government Systems Corporation
Jenner & Block LLC
Swann Tod
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