Abstract: A computer-implemented blockchain based voucher method and system, the method including: recording in a blockchain network, with a user computing device of a user with at least one blockchain based voucher, a purchase request that identifies a proposed purchase with an authorized provider, a purchase amount and the voucher, wherein the voucher comprises a sum of cryptocurrency bound by a set of rules earmarking the voucher to be usable only in transactions between the user and any of a set of one or more authorized providers of goods or services, and wherein the purchase amount is a value that is less than or equal to the total value of the voucher; validating, by the blockchain network, eligibility of the purchase request, based on the set of rules binding the voucher; unbinding the set of rules from the purchase amount of the voucher when the proposed purchase is completed.

Abstract: A method and system for transaction validation in a distributed computing system, the method including: associating first and second parameters with respective users of the distributed computing system, the first parameter being determined based on an increment for each validation performed by a respective user and a decrement for each transaction validation performed by the respective user, the second parameter being determined based on a transaction history and a validation history of the respective users; and associating respective validation priorities in respect of performing a validation task with members of a first set of validating users having at least one of the validating users other than the first of the users, the respective validation priorities being determined based on the first and second parameters associated with the members of the first set of validating users, the validation task comprising validation of the transaction

Abstract: A method and device for protecting elliptic curve cryptography against simple power attacks is disclosed. The method is based on a processor such as a computer equipped to encrypt and decrypt communications and selecting and entering a point P on an elliptic curve in the computer. The processor provides k copies of the point P (kP). The processor is used to divide a string of Ks into two equal length partitions that are scanned from right to left and performing point doubling operation and delay the point addition operation by storing the some doubled points in a buffer for later performing of addition operation.

Abstract: A method of scalar multiplication to obtain the scalar product between a key and a point on an elliptic curve, wherein the secret is m bits long. In selected embodiments, the first step is to partition the secret into two partitions each with m/2 bits. Point-doubling operations are performed on the point and stored into three buffers. Point additions are performed at randomized time intervals thereby preventing the method from being susceptible to differential power analysis attacks.

Abstract: A method and device for protecting elliptic curve cryptography against simple power attacks is disclosed. The method is based on a processor such as a computer equipped to encrypt and decrypt communications and selecting and entering a point P on an elliptic curve in the computer. The processor provides k copies of the point P (kP). The processor is used to divide a string of Ks into two equal length partitions that are scanned from right to left and performing point doubling operation and delay the point addition operation by storing the some doubled points in a buffer for later performing of addition operation.

Abstract: A method of scalar multiplication to obtain the scalar product between a key and a point on an elliptic curve, wherein the secret is m bits long. In selected embodiments, the first step is to partition the secret into two partitions each with m/2 bits. Point-doubling operations are performed on the point and stored into three buffers. Point additions are performed at randomized time intervals thereby preventing the method from being susceptible to differential power analysis attacks.