| 摘要 |
<p>A method is provided for providing a digital signature to prevent the detection of the secret exponent when monitoring power variation. In an apparatus in the form of a microelectronic assembly including an IC circuit, the digital signature is formed by utilizing a square-and multiply algorithm by modular exponentiation of a secret exponent having a plurality of bits characterizing a private key. The method comprises the steps of selecting at least one bit other (302) than the least significant bit (LSB) and the most significant bit (MSB), using the square-and-multiply algorithm, sequentially selecting bits to the left of the at least one predetermined bit for exponentiation until the MSB is selected (304-308), subsequent to selecting the MSB, sequentially selecting bits to the right of the at least one predetermined bit for exponentiation until the LSB is selected (310-314).</p> |
