Cryptography key data storing method for e.g. chip card, involves converting data, from cryptography key and used with operand within Euclidean operation, into data to be used with operand within Montgomery operation

摘要

The method involves converting a data, from a cryptography key and used with a operand within an Euclidean operation e.g. Euclidean multiplication, into a data to be used with the operand within Montgomery operation e.g. Montgomery multiplication, by a device external to an electronic entity. The key data is transmitted from the device to the electronic entity and stored in a non-volatile storage unit of the electronic entity. Independent claims are also included for the following: (A) a data processing method in an electronic entity comprising a non-volatile storage unit (B) a card personalizing device including a data storing device (C) a signature generating device including a data processing device.