1. A key pair management method for use in an image forming device, comprising:
determining, when powering on the image forming device, whether key pairs for each of a plurality of key pair types have been generated and stored in a first area of a memory, the plurality of key pair types each being usable for secure communication between the image forming device and an external device;
generating one or more key pairs corresponding respectively to each of one or more non-generated key pair types, non-generated key pair types being key pair types, from among the plurality or key pair types, for which the determining step determined a key pair has not yet been generated;
storing the one or more generated key pairs in the first area of the memory;
receiving input information identifying a key pair type selected for a first secure communication session with the external device from the first area of the memory;
obtaining a key pair, from among generated key pairs stored in the first area of the memory, having the selected key pair type; and
initiating the first secure communication session between the image forming device and the external device using the obtained key pair.
2. The key pair management method according to claim 1, wherein, at least one of the one or more key pairs corresponding respectively to each of one or more non-generated key pair types is generated in an asynchronous mode and stored in the first area of the memory.
3. The key pair management method according to claim 1, wherein, in the obtaining operation, the obtained key pair is moved from the first area of the memory to a second area of the memory, and the obtained key pair is a key pair that was generated in an asynchronous mode and stored in the first area of the memory.
4. The key pair management method according to claim 1, wherein, in the initiation operation includes using, for authentication and encryption of a communication partner, the selected key pair.
5. A non-transitory computer-readable recording medium storing a key pair managing program which, when executed by a computer, causes the computer to perform key pair management operations for use in an image forming device, the key pair management operations comprising:
determining, when powering on the image forming device, whether key pairs for each of a plurality of key pair types have been generated and stored in a first area of a memory, the plurality of key pair types each being usable for secure communication between the image forming device and an external device;
generating one or more key pairs corresponding respectively to each of one or more non-generated key pair types, non-generated key pair types being key pair types, from among the plurality or key pair types, for which the determining step determined a key pair has not yet been generated;
storing the one or more generated key pairs in the first area of the memory;
receiving input information identifying a key pair type selected for a first secure communication session with the external device from the first area of the memory;
obtaining a key pair, from among the one or more generated key pairs stored in the first area of the memory, having the selected key pair type; and
initiating the first secure communication session between the image forming device and the external device using the obtained key pair.
6. An image forming device comprising:
a processor; and
a memory storing instructions that, when executed by the processor, cause the processor to implement:
a management unit configured to,
determine, when powering on the image forming device, whether key pairs for each of a plurality of key pair types have been generated and stored in a first area of a memory, the plurality of key pair types each being usable for secure communication between the image forming device and an external device, and
generate one or more key pairs corresponding respectively to each of one or more non-generated key pair types, non-generated key pair types being key pair types, from among the plurality or key pair types, for which the determining step determined a key pair has not yet been generated,
a storage unit configured to store the one or more generated key pairs in the first area of the memory,
the management unit being further configured to,
receive input information identifying a key pair type selected for a first secure communication session with the external device from the first area of the memory, and
obtain a key pair, from among the one or more generated key pairs stored in the first area of the memory, having the selected key pair type; and
a communication unit configured to initiate the first secure communication session between the image forming device and the external device using the obtained key pair.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A phase-compensating cube corner retroreflector, comprising:
an entranceexit face devoid of any phase-compensating film stack;
a first rear reflecting face;
a first phase-compensating film stack atop the first rear reflecting face, wherein the first phase-compensating film stack induces 2n\u03c0 phase difference in light upon reflection, wherein n is any integer including 0;
a second rear reflecting face;
a second phase-compensating film stack atop the second rear reflecting face, wherein the second phase-compensating film stack induces 2n\u03c0 phase difference in light upon reflection;
a third rear reflecting face;
a third phase-compensating film stack atop the third rear reflecting face, wherein the third phase-compensating film stack induces the 2n\u03c0 phase difference in light upon reflection;
wherein light enters and exits the cube corner retroreflector with substantially the same polarization orientation and substantially the same polarization ellipticity.
2. The retroreflector of claim 1, wherein the first, the second, and the third phase-compensating film stacks each comprises a stack of thin films wherein reflections from the thin films interfere to induce the 2n\u03c0 phase difference, and an interface between the last film and air provides total internal reflection.
3. The retroreflector of claim 1, wherein the phase-compensating film stack and said another phase-compensating stack each comprises:
a first layer atop the corresponding reflecting face, the first layer comprising of silicon dioxide having an optical thickness of approximately 815 nm;
a second layer atop the first layer, the second layer comprising titanium dioxide having an optical thickness of approximately 1066 nm;
a third layer atop the second layer, the third layer comprising silicon dioxide having an optical thickness of approximately 1090 nm; and
a fourth layer atop the third layer, the fourth layer comprises titanium dioxide having an optical thickness of approximately 1702 nm.
4. The retroreflector of claim 1, wherein the first, the second, and the third phase-compensating film stacks each comprises:
a first layer atop the corresponding reflecting face, the first layer comprising of magnesium dioxide having an optical thickness of approximately 715 nm; and
a second layer atop the first layer, the second layer comprising titanium dioxide having an optical thickness of approximately 1903 nm.
5. The retroreflector of claim 1, wherein the first, the second, and the third phase-compensating film stacks each comprises:
a first layer atop the corresponding reflecting face, the first layer comprising of titanium dioxide having an optical thickness of approximately 262.5 nm;
a second layer atop the first layer, the second layer comprising silicon dioxide having an optical thickness of approximately 346.5 nm;
a third layer atop the second layer, the third layer comprising titanium dioxide having an optical thickness of approximately 1018.5 nm;
a fourth layer atop the third layer, the fourth layer comprises silicon dioxide having an optical thickness of approximately 462 nm; and
a fifth layer atop the fourth layer, the fifth layer comprising titanium dioxide having an optical thickness of approximately 850.5 nm.