Vehicle security device with electronic use authorization coding
First Claim
1. Vehicle security device having an electronic use-authorization coding arrangement comprising:
- a user-end key unit for receiving an item of random information, and for subsequently transmitting an item of user code information which is dependent thereon;
a vehicle-end apparatus for transmitting said item of random information, for subsequently receiving a transmitted item of user code information, and for determining an item of actual authorization information which is dependent on the item of user code information; and
means for comparing said item of actual authorization information with an item of desired authorization information present at the vehicle unit, and for generating an item of use-enabling information based on a result of said comparing, wherein;
successively transmitted items of user code information contain changing inverse images calculated by means of a one-way function, which inverse images are logic linked in coded form to the item of random information;
the vehicle end apparatus includes means for extracting inverse image information from an item of received user code information;
the desired authorization information is in each case a one-way function value of the inverse image contained in an associated item of user code information; and
determination of the actual authorization information from the received user code information includes the formation of a one-way function value of the inverse image contained in the received user code information.
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Accused Products
Abstract
The invention provides a vehicle security device utilizing a rapid encryption method which operates on the basis of a "one-way function" and which requires storage in the vehicle of at most one item of secret coded information in a single piece of equipment, out of any desired number of pieces of equipment involved in vehicle security. In all such pieces of equipment only the one-way function values corresponding to inverse images stored in a key unit need to be present, the reading out of the said one-way function values making unauthorized manufacture of a copied key impossible. Security against interception and storage of information transmitted at the key end in order to produce copied keys is ensured by including an item of random information, transmitted at the vehicle end, in this authentication information.
119 Citations
14 Claims
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1. Vehicle security device having an electronic use-authorization coding arrangement comprising:
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a user-end key unit for receiving an item of random information, and for subsequently transmitting an item of user code information which is dependent thereon; a vehicle-end apparatus for transmitting said item of random information, for subsequently receiving a transmitted item of user code information, and for determining an item of actual authorization information which is dependent on the item of user code information; and means for comparing said item of actual authorization information with an item of desired authorization information present at the vehicle unit, and for generating an item of use-enabling information based on a result of said comparing, wherein; successively transmitted items of user code information contain changing inverse images calculated by means of a one-way function, which inverse images are logic linked in coded form to the item of random information; the vehicle end apparatus includes means for extracting inverse image information from an item of received user code information; the desired authorization information is in each case a one-way function value of the inverse image contained in an associated item of user code information; and determination of the actual authorization information from the received user code information includes the formation of a one-way function value of the inverse image contained in the received user code information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification