| Class Number |
Class Name |
No. of Patents |
| 380/54 |
By modifying optical image (e.g., transmissive overlay) |
488 |
| 380/247 |
Cellular telephone cryptographic authentication |
625 |
| 380/249 |
Initialization |
150 |
| 380/250 |
Usage pattern detection |
115 |
| 380/248 |
Visiting center |
136 |
| 380/255 |
Communication system using cryptography |
895 |
| 380/257 |
Circuit switched network (e.g., wired telephone) |
138 |
| 380/41 |
Having quantizing and subsequent normalizing of signal (e.g., reentry telephone circuitry) |
44 |
| 380/267 |
Correcting for random appearance of control character code |
39 |
| 380/42 |
Data stream/substitution enciphering |
415 |
| 380/43 |
Key sequence signal combined with data signal |
381 |
| 380/256 |
Fiber optic network |
243 |
| 380/38 |
Frequency shift or inversion |
78 |
| 380/39 |
Having plural band pass filters |
32 |
| 380/269 |
Having compression |
165 |
| 380/40 |
Having plural band pass filters |
35 |
| 380/258 |
Position dependent or authenticating |
266 |
| 380/268 |
Pseudo-random sequence scrambling |
356 |
| 380/275 |
Speech scrambler detail |
92 |
| 380/276 |
Including sampling |
59 |
| 380/259 |
Symmetric key cryptography |
488 |
| 380/265 |
Combining outputs of shift register |
122 |
| 380/266 |
Including a modem |
73 |
| 380/264 |
Key derived from addressable memory element |
171 |
| 380/260 |
Symmetric key synchronization |
253 |
| 380/261 |
Including frame synchronization |
133 |
| 380/263 |
Nonlinear or chaotic system |
168 |
| 380/262 |
Transmitting a seed, sequence, or initial value |
397 |
| 380/36 |
Time segment interchange |
84 |
| 380/37 |
Block/data stream enciphering |
667 |
| 380/35 |
Variable time delay modulation |
66 |
| 380/270 |
Wireless communication |
1103 |
| 380/271 |
Having receiver selection (e.g., pager) |
97 |
| 380/272 |
Including hand-off based cryptographic alteration |
94 |
| 380/31 |
Plural modulation of single carrier |
58 |
| 380/32 |
Wobbling of carrier |
11 |
| 380/273 |
Rekeying system |
228 |
| 380/274 |
Synchronization |
170 |
| 380/33 |
Using plural paths or channels |
183 |
| 380/34 |
Plural carrier frequencies |
460 |
| 380/1 |
Cryptanalysis |
109 |
| 380/252 |
Electric signal masking |
191 |
| 380/253 |
By signal having discrete frequency component |
42 |
| 380/254 |
By signal having discrete step amplitude variation |
29 |
| 380/287 |
Electric signal modification |
135 |
| 380/22 |
Having magnetic record carrier (e.g., tape, drum) |
85 |
| 380/26 |
Having mechanical control of signal encryption (e.g., cam) |
38 |
| 380/27 |
By perforated record |
16 |
| 380/51 |
Having production of printed copy (e.g., printer, typewriter) |
414 |
| 380/52 |
Including particular structure or housing (e.g., display, keyboard) |
171 |
| 380/53 |
Audio transducer mounting or structure |
13 |
| 380/251 |
Electronic game using cryptography |
130 |
| 380/2 |
Equipment test or malfunction indication |
172 |
| 380/243 |
Facsimile cryptography |
179 |
| 380/246 |
Including generation of an associated coded record |
60 |
| 380/245 |
Nonstandard scan pattern |
22 |
| 380/244 |
Synchronization |
19 |
| 380/55 |
Having production of printed copy (e.g., cryptographic printer or typewriter) |
223 |
| 380/277 |
Key management |
2029 |
| 380/44 |
Having particular key generator |
1460 |
| 380/45 |
Multiple key level |
422 |
| 380/46 |
Nonlinear (e.g., pseudorandom) |
839 |
| 380/47 |
Plural generators |
270 |
| 380/278 |
Key distribution |
1122 |
| 380/279 |
Key distribution center |
527 |
| 380/282 |
By public key method |
519 |
| 380/280 |
Control vector or tag |
167 |
| 380/281 |
Using master key (e.g., key-encrypting-key) |
493 |
| 380/283 |
User-to-user key distributed over data link (i.e., no center) |
442 |
| 380/285 |
By public key method |
345 |
| 380/284 |
Using master key (e.g., key-encrypting-key) |
314 |
| 380/286 |
Key escrow or recovery |
412 |
| 380/59 |
Miscellaneous |
249 |
| 380/28 |
Particular algorithmic function encoding |
1851 |
| 380/29 |
Nbs/des algorithm |
570 |
| 380/30 |
Public key |
1538 |
| 380/56 |
Selectively movable element having code characters |
35 |
| 380/57 |
Rotatable |
19 |
| 380/58 |
Characters on peripheral surface (e.g., cylinder section) |
8 |
| 380/200 |
Video cryptography |
579 |
| 380/201 |
Copy protection or prevention |
1378 |
| 380/203 |
Having copy protect signal |
532 |
| 380/202 |
Having origin or program id |
360 |
| 380/204 |
Modifying sync signal |
157 |
| 380/205 |
Video electric signal masking |
127 |
| 380/208 |
Including filter for removing masking signal |
49 |
| 380/207 |
Including locally generated masking signal |
47 |
| 380/206 |
Masking of synchronization signal |
48 |
| 380/209 |
Masking signal selectively addressed |
54 |
| 380/210 |
Video electric signal modification (e.g., scrambling) |
514 |
| 380/221 |
By modifying synchronizing signal |
91 |
| 380/222 |
Including phase inversion of scan line information |
32 |
| 380/224 |
Including pseudo-synchronizing pulse |
38 |
| 380/226 |
Key signal in blanking interval |
71 |
| 380/223 |
Key signal on separate carrier |
77 |
| 380/225 |
Self-synchronizing circuit at receiver |
53 |
| 380/220 |
Carrier frequency conversion |
38 |
| 380/219 |
Carrier phase shift |
25 |
| 380/213 |
Chrominance scrambling |
59 |
| 380/239 |
Encrypted code control signal |
452 |
| 380/216 |
Image data converted to digital before modification |
134 |
| 380/217 |
Having compression (e.g., mpeg) |
277 |
| 380/240 |
Including addressed decoder control signal |
218 |
| 380/242 |
Having command signal for receiver |
156 |
| 380/241 |
Having program id or authorization |
299 |
| 380/211 |
Interactive tv |
159 |
| 380/236 |
Modifying accompanying audio signal |
92 |
| 380/237 |
Including digital audio |
80 |
| 380/238 |
Including frequency modification of audio signal or frequency shifting of audio carrier |
62 |
| 380/214 |
Nonstandard scan pattern of video information |
52 |
| 380/215 |
Line cut and shuffle |
59 |
| 380/235 |
Phase inversion of scan line information |
46 |
| 380/212 |
Plural video stream multiplexing |
199 |
| 380/227 |
Record or coin controlled |
135 |
| 380/229 |
Including authentication |
252 |
| 380/228 |
Including key on record |
223 |
| 380/230 |
Including usage recording |
114 |
| 380/231 |
Usage or charge determination |
224 |
| 380/232 |
Including authentication |
195 |
| 380/234 |
Including display of supplemental information |
65 |
| 380/233 |
Including usage or charge recording at subscriber station |
87 |
| 380/218 |
Variable time delay modulation of baseband video signal |
56 |
