Keiichi Iwamura
90Patents
26h-index
31Co-inventors
88Inventor score
Filing activity: Mar 20, 1986 → Apr 26, 2007
Most-cited inventions
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US6425081B1 | Electronic watermark system electronic information distribution system and image filing apparatus | Electricity | 264 | Expired |
| US6144946A | Accounting device, communicating apparatus, and communication system | Physics | 210 | Expired |
| US6275988A | Image transmission apparatus, image transmission system, and communication apparatus | Electricity | 103 | Expired |
| US6307940A | Communication network for encrypting/deciphering communication text while updating encryption key, a communication terminal thereof, and a communication method thereof | Electricity | 91 | Expired |
| US5708714A | Method for sharing secret information and performing certification in a communication system that has a plurality of information processing apparatuses | Electricity | 85 | Expired |
| US6088454A | Key management method, encryption system, and sharing digital signature system which have hierarchies | Electricity | 81 | Expired |
| US6513118B1 | Electronic watermarking method, electronic information distribution system, image filing apparatus and storage medium therefor | Electricity | 80 | Expired |
| US6674874B1 | Data processing apparatus and method and storage medium | Physics | 72 | Expired |
| US6560339B1 | Electronic watermarking method, digital information distribution system using such method, and storage medium storing program of such method | Electricity | 70 | Expired |
| US6807285B1 | Embedding information in digital image data | Electricity | 67 | Expired |
| US5600720A | Encryption apparatus, communication system using the same and method therefor | Electricity | 60 | Expired |
| US5321752A | Method of and apparatus for encryption and decryption of communication data | Physics | 53 | Expired |
| US5524090A | Apparatus for multiplying long integers | Physics | 53 | Expired |
| US5666419A | Encryption device and communication apparatus using same | Electricity | 51 | Expired |
| US5937395A | Accounting apparatus, information receiving apparatus, and communication system | Physics | 45 | Expired |
| US6535616B1 | Information processing apparatus, method and memory medium therefor | Electricity | 42 | Expired |
| US6434253B1 | Data processing apparatus and method and storage medium | Electricity | 42 | Expired |
| US4747103A | Signal processing apparatus for correcting decoding errors | Electricity | 42 | Expired |
| US5909238A | Image transmission system with billing based on the kind of MPEG frame transmitted | Electricity | 42 | Expired |
| US7142689B2 | Image processing apparatus for determining specific images | Electricity | 42 | Expired |
| US6707465B2 | Data processing apparatus and method, and storage medium | Physics | 39 | Expired |
| US7530031B2 | Character input device | Physics | 36 | Expired |
| US6272535A | System for enabling access to a body of information based on a credit value, and system for allocating fees | Physics | 36 | Expired |
| US6671675B2 | Metering the flow of electronic information | Physics | 33 | Expired |
| US5313530A | Calculating apparatus and method of encrypting/decrypting communication data by using the same | Physics | 29 | Expired |
Source: USPTO / EPO open patent data. Inventor disambiguation is heuristic; counts are objective bibliographic measures.