Patent ID: 7916860

Claim:
A scalar multiplication apparatus, comprising: a first encryptor for receiving an input point and a changed secret key to generate a first encrypted output point; a second encryptor for receiving the first encrypted output point and the changed secret key to perform an inverse operation and generate a second encrypted output point; a first XOR circuit for receiving the input point and the second encrypted output point to perform a first XOR operation; a second XOR circuit for receiving the first XOR operation result of the first XOR circuit and a secret key to perform a second XOR operation and generate the changed secret key; and a random number generator for generating random number data; wherein the first encryptor generates the first encrypted output point from the input point and secret key by performing an elliptic curve (EC) operation, wherein the first encryptor generates the second encrypted output point for a subsequent operation from the first encrypted output point of a previous operation by performing the EC operation, wherein the first and second encrypted output points are generated for at least two operations, wherein the second encryptor generates the second encrypted output point for every operation from the first encrypted output point and secret key by performing an inverse EC operation, wherein the first XOR circuit performs the first XOR operation for every operation on the first encrypted output point generated in each operation by the first encryptor and the second encrypted output point generated in each operation by the second encryptor, wherein the first XOR circuit receives the input point, the second encrypted output point, and the random number data to perform the first XOR operation of the input point, and wherein the second XOR circuit receives the first XOR operation result, the secret key, and the random number data to perform the second XOR operation.