 Audio system for vehicular application |
| Systems and methods in accordance with the invention enable virtually infinite segmentation and ... |
|
| Medium having photographically recorded digital audio bits |
| The invention is a medium (such as motion picture film) having digital audio signals ... |
|
| Digital hearing aid |
| Therefore, it is an object of the present invention to provide a digital hearing aid which can ... |
|
| Apparatus for creating 3D audio imaging over headphones using binaural synthesis |
| Accordingly, it is an object of the present invention to provide an apparatus for creating three-... |
|
| System, apparatus, and method for improving speech quality in multi-party devices |
| A method, system, and apparatus are provided, such that cross talk terms may be removed from speech ... |
|
| Speaker excursion control system |
| OF THE PREFERRED EMBODIMENT Referring initially to FIG. 1, there is shown a sound system which may ... |
|
| Portable information terminal device with radio selective-calling receiver |
| In view of the foregoing, it is an object of the present invention to provide a portable ... |
|
| Digital graphic equalizer |
| An object of the invention is to remedy the major problems of prior digital graphic equalizers and, ... |
|
| Electric artificial larynx |
| It is an object of the present invention which has been made to solve the above problem to provide ... |
|
| Audio reproducing apparatus corresponding to picture |
| In view of such aspects, an object of the present invention is to provide an audio reproducing ... |
|
|
Group key distribution
| Details |
Inventors: Harkins, Dan;
Assignee: Cisco Technology, Inc. (San Jose, CA)
Primary Examiner: Barron, Jr.; Gilberto
Assistant Examiner: Darrow; Justin T.
Attorney, Agent or Firm: Carr & Ferrell LLP
A method for distributing a secret key from a key holder H to intended group members M. The method assumes that during the distribution process each party, a group member M and the key holder H, can decrypt and encrypt exchanged information such that the encrypter knows that the decrypter will be the intended party. The method preferably uses a public key/private key encryption technique in which, for example, a trusted Certificate Authority in a public key infrastructure signs the certificates to provide the public keys involved in the encryption. Alternatively, the method, together with a symmetric cipher, uses a shared secret, established in an authenticated mechanism that is outside the information exchanges of the invention. Additionally, the method uses a strong mixing function that takes several items of data as input and produces a pseudo-random authentication (or digest). Inputs to the mixing function include identity stamps that are generated by each member M and key holder H. These inputs can be the identity of the stamp generator, such as a network address, port, or protocol, a timestamp, and/or a secret value that is known only to the stamp generator. The stamps include information to bind member M if generated by key holder H, and to bind key holder H if generated by member M. Consequently, the invention authenticates each communication exchange between member M and key holder H. |
|
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention provides a group key distribution technique useful for both unicast and multicast applications.
Unicast (or point cast) operations transmit messages to one machine, node, or "point" which is the only node or point that can receive the message.
A closed-circuit video, for example, is a unicast operation.
Multicast operations send messages to many machines that can receive the signals simultaneously, as in general television broadcasting.
The invention creates a secure group in which a key holder H holds a secret key K.
Based on a controlled policy, key holder H can explicitly deny or permit a requester to access to key K, which is preferably a number, chosen randomly by any of various methods such as, for example, based on the controlled policy, deriving the number from a Diffie-Hellman exchange with any two group members.
For illustrative purposes, this Specification uses the following notations: Request R: a message sent by member M to key holder H to request the secret key K.
Stamp C.
sub.
m : a code generated by member M that includes key holder H's identity, is unique to and binds key holder H to each sequence of information exchanges ((1) through (4) below).
Stamp C.
sub.
h : a code generated by key holder H that includes member M's identity, is unique to and binds member M to each sequence of information exchanges ((1) through (4) below).
Each stamp C.
sub.
m or C.
sub.
h is preferably a pseudo-random bit stream generated from a function, which, given the same input, repeatedly produces the same output.
For example, each stamp C.
sub.
m and C.
sub.
h can result from combining in a strong mixing function, such as the Secure Hash Standard or HMAC-SHA, the other party's identity (key holder H's identity for stamp C.
sub.
m and member M's identity for stamp C.
sub.
h), a timestamp, and a secret, preferably a number, known only to the stamp generator.
Authorization: a response from key holder H to member M's request.
Code R.
sub.
m : a random number chosen by member M
|
|
Audio Signal Processing 
