Patent ID: 8139767

Claim:
A method comprising providing a secret cryptographic key and a public cryptographic key applicable in a network of connected computer nodes using a signature scheme, the method being executable by a first computer node and the step of providing comprising: using an apparatus configured to adapt a transmission parameter to a current link quality of a data communication channel to perform steps of: generating the secret cryptographic key by: selecting two random factor values; multiplying the two selected random factor values to obtain a modulus value; and selecting a secret base value in dependence on the modulus value, wherein the secret base value forms part of the secret cryptographic key; generating the public cryptographic key by selecting a number of exponent values, and deriving a public base value from the exponent values and the secret base value, wherein the public base value and the modulus value form part of the public cryptographic key; deleting the two random factor values; providing the public cryptographic key within the network, such that the public cryptographic key and at least one of the selected exponent values is usable for verifying a signature value on a message to be sent within the network to a second computer node for verification; publishing a parameter as part of the public cryptographic key, wherein said parameter sets a time-period during which a user is able to note that the secret cryptographic key was compromised; using the public cryptographic key and at least one of the selected exponent values usable for verifying a signature value on a message; sending the message to a second computer node within the network for verification; and aborting signing of the message when the public cryptographic key has been revoked.