Abstract: An encrypting apparatus includes a digest part using a SHA-2 algorithm of which a basic unit of operation is 32*Y (Y=1 or 2) bits. The digest part includes a shift register including a series of registers, and a predetermined number of adders performing an addition operation based on data stored in the shift register. The shift register includes a (32*Y)/X-bit register, where X=2k (k is an integer such that 1?k?4 when Y=1 and 1?k?5 when Y=2). Each of the adders has a data width of (32*Y)/X bits and performs the addition operation in each cycle in which the data stored in the shift register is shifted between the registers with the data width of (32*Y)/X bits.

Abstract: An encryption/decryption circuit includes a swap circuit for outputting each of text data and initialization vector data which are input from an input terminal to either a first or second output terminal in accordance with one of modes of operation, an encryption/decryption processing unit to which one of the text data and the initialization vector data are input from the first output terminal and which performs encryption processing and decryption processing on the data, and an exclusive OR processing unit to which another one of the initialization vector data and the text data are input from the second output terminal and which performs an exclusive OR operation on the data.

Abstract: A power supply circuit for supplying power to a load includes an antenna which receives electric power, a rectifier coupled to the antenna and configured to convert an alternating voltage supplied from the antenna into a direct-current voltage, a voltage step-down circuit which steps down the direct-current voltage to generate an output voltage for provision to the load, a regulator which controls a resistance connected between the output voltage and a ground voltage in parallel with the load, thereby controlling a voltage level of the output voltage.

Abstract: A power supply circuit for supplying power to a load includes an antenna which receives electric power, a rectifier coupled to the antenna and configured to convert an alternating voltage supplied from the antenna into a direct-current voltage, a voltage step-down circuit which steps down the direct-current voltage to generate an output voltage for provision to the load, a regulator which controls a resistance connected between the output voltage and a ground voltage in parallel with the load, thereby controlling a voltage level of the output voltage.

Abstract: A CMOS inverter capable of operating at low voltages is provided. The gate of a p-channel MOS transistor and the gate of an n-channel MOS transistor are AC coupled to an input terminal via first and second capacitors, respectively. Signals whose amplitude centers are optimized according to the threshold voltages of the p- and n-channel MOS transistors by bias voltages from first and second variable voltage sources, respectively, are supplied to the gates of these MOS transistors. In consequence, the CMOS inverter can operate at high speeds at low power supply voltages without being affected by the threshold voltages.

Abstract: A CMOS inverter capable of operating at low voltages is provided. The gate of a p-channel MOS transistor and the gate of an n-channel MOS transistor are AC coupled to an input terminal via first and second capacitors, respectively. Signals whose amplitude centers are optimized according to the threshold voltages of the p- and n-channel MOS transistors by bias voltages from first and second variable voltage sources, respectively, are supplied to the gates of these MOS transistors. In consequence, the CMOS inverter can operate at high speeds at low power supply voltages without being affected by the threshold voltages.