Secure cryptographic methods for electronic transfer of information
OwnerStefanus Alfonsus Brandsinventor
Life of this patent
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Abstract
Cryptographic methods and apparatus are disclosed relating to practical cryptographic systems for electronic transfer of information. Specifically, inventive techniques are described to allow the use of tamper-resistant computing devices without powerful processors; to guarantee security against criminals able to gain full control over computing devices of other parties; to allow value in privacy-protected off-line cash systems to be represented by counters instead of digital coins, without significantly compromising security against criminals who can by-pass tamper-resistance; and to allow secure currency conversion in privacy-protected off-line cash systems, without requiring tamper-resistance for receiver parties.
Claims4
A method for a tamper-resistant first computing device to perform a cryptographic action with respect to a public key, the first computing device being held by a party that also holds a user-controlled second computing device, the method comprising the steps of:
- computing by the second computing device, at least one number based on at least a first secret key held by the second computing device, the at least one number being substantially uncorrelated to the first secret key;
- providing by the second computing device to the first computing device, the at least one number;
- and
- computing by the first computing device, at least one output based on at least the at least one number and a second secret key held by the first computing device, a function of the first and second secret keys being equal to a third secret key corresponding to the public key.
A method for a tamper-resistant first computing device to perform a cryptographic action based on a first secret key, the first computing device being held by a party also holding a user-controlled second computing device, the method comprising the steps of:
- providing by the second computing device to the first computing device, a second secret key;
- computing by the first computing device, at least one output based on at least the second secret key and a third secret key, the first secret key being a function of the second and third secret keys;
- and
- erasing by the first computing device, the second secret key.
Dependencies are inferred from the claim text.