Abstract: A fuel cell system includes a fuel cell stack, an oxygen-containing gas supply apparatus, a fuel gas supply apparatus, a pressure reduction apparatus, and a dilution apparatus. The oxygen-containing gas supply apparatus supplies an oxygen-containing gas to the fuel cell stack. The oxygen-containing gas supply apparatus is capable of supplying the air to the fuel gas flow field at the time of stopping operation of the fuel cell system. The fuel gas supply apparatus supplies a fuel gas to the fuel cell stack. The pressure reduction apparatus suctions gases in the oxygen-containing gas flow field and the fuel gas flow field. The dilution apparatus dilutes the fuel gas suctioned by the pressure reduction apparatus using the air.

Abstract: Disclosed is an electrode electrolyte for solid polymer fuel cells, which uses a polymer electrolyte containing a polyarylene copolymer containing a nitrogen-containing aromatic ring having a substituent represented by —SO3H, —(O(CH2)hSO3H or —O(CF2)hSO3H (wherein h represents an integer of 1-12). By having such a constitution, the electrode electrolyte for solid polymer fuel cells can be produced at a low cost, while being excellent in proton conductivity, dimensional stability, hydrothermal resistance and mechanical strength. In addition, this electrode electrolyte for solid polymer fuel cells enables to recover a catalyst metal.

Abstract: Disclosed is an electrode electrolyte for solid polymer fuel cells, which uses a polymer electrolyte containing a polyarylene copolymer containing a nitrogen-containing aromatic ring having a substituent represented by —SO3H, —(O(CH2)hSO3H or —O(CF2)hSO3H (wherein h represents an integer of 1-12). By having such a constitution, the electrode electrolyte for solid polymer fuel cells can be produced at a low cost, while being excellent in proton conductivity, dimensional stability, hydrothermal resistance and mechanical strength. In addition, this electrode electrolyte for solid polymer fuel cells enables to recover a catalyst metal.

Abstract: A fuel cell system includes a fuel cell stack, an oxygen-containing gas supply apparatus, a fuel gas supply apparatus, a pressure reduction apparatus, and a dilution apparatus. The oxygen-containing gas supply apparatus supplies an oxygen-containing gas to the fuel cell stack. The oxygen-containing gas supply apparatus is capable of supplying the air to the fuel gas flow field at the time of stopping operation of the fuel cell system. The fuel gas supply apparatus supplies a fuel gas to the fuel cell stack. The pressure reduction apparatus suctions gases in the oxygen-containing gas flow field and the fuel gas flow field. The dilution apparatus dilutes the fuel gas suctioned by the pressure reduction apparatus using the air.

Abstract: There are provided an encipher method of enciphering message data made by a microcomputer or the like at a high speed by using encipher keys which have previously been stored in a smart card or the like and a decipher method of deciphering the ciphertext made by the encipher method at a high speed by using the encipher keys. The encipher method and the decipher method are suitable for, particularly, a 32-bit microcomputer and include a process expressed by the function Rot.sub.2 i(x) (i=2, 3, 4) in each process. Rot.sub.2 i(x) is the process to circular shift a data train x of 32 bits to the left or right by 2.sup.i bits (i=2, 3, 4).

Abstract: There are provided an encipher method of enciphering message data made by a microcomputer or the like at a high speed by using encipher keys which have previously been stored in a smart card or the like and a decipher method of deciphering the ciphertext made by the encipher method at a high speed by using the encipher keys. The encipher method and the decipher method are suitable for, particularly, a 32-bit microcomputer and include a process expressed by the function Rot.sub.2 i(x) (i=2, 3, 4) in each process. Rot.sub.2 i(x) is the process to circular shift a data train x of 32 bits to the left or right by 2.sup.i bits (i=2, 3, 4).

Abstract: A data encrypting system according to the CBC system involves a limitation in a range of a numerical value which expresses data (smaller than a predetermined integer N). The encrypting system has an encrypting apparatus including a block encrypting section for receiving data, which is expressed by an integer value X smaller than a predetermined integer value N, for executing a data conversionC=enc (X)where 0.ltoreq.C.ltoreq.N-1 using an RSA algorithm, and for outputting C; and an arithmetic operating section connected to receive data, as one input, which is expressed by an integer value M smaller than the integer value N, and the output C of the block encrypting section as the other input, for performing an arithmetic operation for both of the inputs so that a resultant arithmetic value is smaller than the integer value N, and for outputting the arithmetic value as an input of the block encrypting section.