Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
224 words
A method of initialising cryptovariables in a multiterminal network which uses a public key algorithm and wherein the number of terminals is not essentially limited, the method comprising establishing a key distribution centre within the network; generating a public and secret key pair for the key distribution centre; providing a cryptographic facility in each terminal that is intended to be secure; storing the public key of the key distribution centre in each such cryptographic facility; providing and storing at the key distribution centre, for each authorised entity - user or terminal - an individual identification; and informing an initialiser - the user or an appointee in the case of a terminal - of two expiration times for the purposes of registering a cryptovariable with the key distribution centre in order that the initialiser can generate a cryptovariable at a or the terminal, using the cryptographic facility and transmit over the network to the key distribution centre a registration request message including the identification and the cryptovariable pair before the first of the expiration times; the key distribution centre temporarily registering the cryptovariable against the identification, if received before the first expiration time and, if any further communication is received before the second expiration period in respect thereof, cancelling the registration, whereas, after the second expiration period, only cancelling the registration upon proof of authorisation.
Claim 2
Independent Claim
224 words
A method of initialising cryptovariables in a multiterminal network which uses a public key algorithm and wherein the number of terminals is not essentially limited, the method comprising establishing a key distribution centre within the network; generating a public and secret key pair for the key distribution centre; providing a cryptographic facility in each terminal that is intended to be secure; storing the public key of the key distribution centre in each such cryptographic facility; providing and storing at the key distribution centre, for each authorised entity - user or terminal - an individual identification; and informing an initialiser - the user or an appointee in the case of a terminal - of two expiration times for the purposes of registering a cryptovariable with the key distribution centre in order that the initialiser can generate a cryptovariable at a or the terminal, using the cryptographic facility and transmit over the network to the key distribution centre a registration request message including the identification and the cryptovariable pair before the first of the expiration times; the key distribution centre temporarily registering the cryptovariable against the identification, if received before the first expiration time and, if any further communication is received before the second expiration period in respect thereof, cancelling the registration, whereas, after the second expiration period, only cancelling the registration upon proof of authorisation.
Claim 3
Dependent Claim
71 words
A method as claimed in claim 1 wherein the request message transmitted to the key distribution centre includes time variant data and the step of temporarily registering the cryptovariable includes the step of acknowledging the temporary registration of the cryptovariable by sending a message to the requesting terminal containing the identification, the public key, the time variant data echoed, and a signature using the secret key of the key distribution centre.
Claim 4
Independent Claim
84 words
A method as claimed in either preceding claim, further comprising the step of preparing and transmitting to the key distribution centre prior to the second expiration time a identification invalidation request message in the event that neither of a positive acknowledgement from the key distribution centre stating that the requested public key was temporarily registered at the key distribution centre and a positive acknowledgement from the key distribution centre stating that the requested identification has been invalidated by the key distribution centre is received.
Claim 5
Independent Claim
53 words
A method as claimed in any preceding claim, further comprising the steps of: requesting the key distribution centre to provide a verification of the cryptovariable registration for the identification after the second expiration time has passed; and providing verification of the registration if the identification is valid and a cryptovariable was previously registered.
Claim 6
Dependent Claim
44 words
A method as claimed in claim 4 wherein the step of providing verification of the registration is provided by sending a message specifying the registered public key for that entity, the identification and a signature using the secret key of the key distribution centre.
Claim 7
Independent Claim
35 words
A method as claimed in any preceding claim, wherein the public key of the key distribution centre is installed in each terminal at a central location before shipping the terminal to its point of use.
Claim 8
Independent Claim
28 words
A method as claimed in any preceding claim, wherein the step of generating is performed by generating a public key and secret key pair for each authorised entity.
Claim 9
Independent Claim
29 words
A method as claimed in any of claims 1 to 6, wherein the step of generating is performed by generating a secret authorised entity key using a symmetric algorithm.
Claim 10
Independent Claim
43 words
A method as claimed in any preceding claim, further including proving the identification of the designated initialiser after the second expiration time has passed; and requesting the invalidation of the identification if the requested cryptovariable was not registered with the key distribution centre.
Claim 11
Independent Claim
29 words
A method as claimed in any preceding claim, wherein, where an authorised entity is a user, the cryptovariable is recorded on a medium readable by terminals in the network.