SUBJECT MATTER UNDER THIS CLASS:This class includes equipment and processes which
(a) conceal or obscure intelligible information by transforming such information so as to make the information unintelligible to a casual or unauthorized recipient, or
(b) extract intelligible information from such a concealed representation, including breaking of unknown codes and messages.
(1) Note. Cryptographic processing may include, e.g., scrambling or masking or their complementary transformations.
(2) Note. All electrical communications equipment which processes an information signal for purposes of concealment are classified in this class.
(3) Note. Processing or converting of a signal for purposes of handling or transmission which may incidentally render a signal unintelligible are not classified in this class.
(4) Note. Mere blocking of access to the information is not considered a cryptographic transformation of the signal or information.
(5) Note. A cryptogram or a cryptographic record absent a separate encrypting or decrypting device is classified elsewhere. See References to Other Classes, below.
(6) Note. Excluded herein is nominal cryptography in combination with subject matter of another class. Such subject matter is classified with the other class. See search notes below.
(7) Note. Excluded herein is subject matter of this class in combination with the specific environments of a) business data processing or b) electrical computer or digital processing system support. Such subject matter is classified elsewhere in the classes providing for the specific environment. See search notes below.
(8) Note. During the latest reclassification project, a group of existing subclasses were repositioned as is pending additional reclassification of this class. However, screening was not done within this group of subclasses or between this group and the other subclasses not part of the latest project. This should be taken into consideration when determining an appropriate field of search. |
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1 • CRYPTANALYSIS
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2 • EQUIPMENT TEST OR MALFUNCTION INDICATION
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200 • VIDEO CRYPTOGRAPHY
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201 • Copy protection or prevention
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202 • Having origin or program ID
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203 • Having copy protect signal
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204 • Modifying sync signal
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205 • Video electric signal masking
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206 • Masking of synchronization signal
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207 • Including locally generated masking signal
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208 • Including filter for removing masking signal
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209 • Masking signal selectively addressed
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210 • Video electric signal modification (e.g., scrambling)
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211 • Interactive TV
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212 • Plural video stream multiplexing
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213 • Chrominance scrambling
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214 • Nonstandard scan pattern of video information
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215 • Line cut and shuffle
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216 • Image data converted to digital before modification
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217 • Having compression (e.g., MPEG)
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218 • Variable time delay modulation of baseband video signal
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219 • Carrier phase shift
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220 • Carrier frequency conversion
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221 • By modifying synchronizing signal
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222 • Including phase inversion of scan line information
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223 • Key signal on separate carrier
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224 • Including pseudo-synchronizing pulse
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225 • Self-synchronizing circuit at receiver
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226 • Key signal in blanking interval
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227 • Record or coin controlled
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228 • Including key on record
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229 • Including authentication
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230 • Including usage recording
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231 • Usage or charge determination
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232 • Including authentication
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233 • Including usage or charge recording at subscriber station
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234 • Including display of supplemental information
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235 • Phase inversion of scan line information
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236 • Modifying accompanying audio signal
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237 • Including digital audio
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238 • Including frequency modification of audio signal or frequency shifting of audio carrier
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239 • Encrypted code control signal
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240 • Including addressed decoder control signal
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241 • Having program ID or authorization
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242 • Having command signal for receiver
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243 • FACSIMILE CRYPTOGRAPHY
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244 • Synchronization
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245 • Nonstandard scan pattern
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246 • Including generation of an associated coded record
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247 • CELLULAR TELEPHONE CRYPTOGRAPHIC AUTHENTICATION
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248 • Visiting center
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249 • Initialization
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250 • Usage pattern detection
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251 • ELECTRONIC GAME USING CRYPTOGRAPHY
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252 • ELECTRIC SIGNAL MASKING
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253 • By signal having discrete frequency component
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254 • By signal having discrete step amplitude variation
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255 • COMMUNICATION SYSTEM USING CRYPTOGRAPHY
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256 • Fiber optic network
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257 • Circuit switched network (e.g., wired telephone)
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41 • Having quantizing and subsequent normalizing of signal (e.g., reentry telephone circuitry)
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258 • Position dependent or authenticating
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259 • Symmetric key cryptography
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260 • Symmetric key synchronization
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261 • Including frame synchronization
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262 • Transmitting a seed, sequence, or initial value
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263 • Nonlinear or chaotic system
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264 • Key derived from addressable memory element
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265 • Combining outputs of shift register
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266 • Including a modem
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267 • Correcting for random appearance of control character code
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268 • Pseudo-random sequence scrambling
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269 • Having compression
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270 • Wireless communication
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271 • Having receiver selection (e.g., pager)
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272 • Including hand-off based cryptographic alteration
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273 • Rekeying system
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31 • Plural modulation of single carrier
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32 • Wobbling of carrier
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33 • Using plural paths or channels
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34 • Plural carrier frequencies
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274 • Synchronization
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35 • Variable time delay modulation
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36 • Time segment interchange
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37 • Block/data stream enciphering
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38 • Frequency shift or inversion
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39 • Having plural band pass filters
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40 • Having plural band pass filters
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42 • Data stream/substitution enciphering
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43 • Key sequence signal combined with data signal
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275 • Speech scrambler detail
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276 • Including sampling
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277 • KEY MANAGEMENT
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278 • Key distribution
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279 • Key distribution center
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280 • Control vector or tag
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281 • Using master key (e.g., key-encrypting-key)
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282 • By public key method
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283 • User-to-user key distributed over data link (i.e., no center)
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284 • Using master key (e.g., key-encrypting-key)
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285 • By public key method
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286 • Key escrow or recovery
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44 • Having particular key generator
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45 • Multiple key level
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46 • Nonlinear (e.g., pseudorandom)
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47 • Plural generators
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28 • PARTICULAR ALGORITHMIC FUNCTION ENCODING
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29 • NBS/DES algorithm
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30 • Public key
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287 • ELECTRIC SIGNAL MODIFICATION
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22 • Having magnetic record carrier (e.g., tape, drum)
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26 • Having mechanical control of signal encryption (e.g., cam)
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27 • By perforated record
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51 • Having production of printed copy (e.g., printer, typewriter)
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52 • Including particular structure or housing (e.g., display, keyboard)
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53 • Audio transducer mounting or structure
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54 • BY MODIFYING OPTICAL IMAGE (E.G., TRANSMISSIVE OVERLAY)
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55 • HAVING PRODUCTION OF PRINTED COPY (E.G., CRYPTOGRAPHIC PRINTER OR TYPEWRITER)
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56 • SELECTIVELY MOVABLE ELEMENT HAVING CODE CHARACTERS
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57 • Rotatable
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58 • Characters on peripheral surface (e.g., cylinder section)
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59 • MISCELLANEOUS
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FOR103 • STORED INFORMATION ACCESS OR COPY PREVENTION (380/3)
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FOR104 • Digital data (e.g., software program protection, data encryption) (380/4)
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FOR105 • Video (380/5)
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FOR106 • ELECTRIC SIGNAL MASKING (380/6)
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FOR107 • Video (380/7)
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FOR108 • By signal having discrete step amplitude variation (380/8)
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FOR109 • ELECTRIC SIGNAL MODIFICATION (E.G., SCRAMBLING) (380/9)
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FOR110 • Video (380/10)
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FOR111 • Variable time delay modulation of baseband video signal (380/11)
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FOR112 • Carrier phase shift (380/12)
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FOR113 • Carrier frequency conversion (380/13)
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FOR114 • Nonstandard scan of video information (380/14)
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FOR115 • By modifying synchronizing signal (380/15)
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FOR116 • Record or coin controlled (380/16)
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FOR117 • Phase inversion of scan line information (380/17)
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FOR118 • Facsimile (380/18)
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FOR119 • Encrypting of accompanying audio signal (380/19)
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FOR120 • Control coding (380/20)
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FOR121 • Having transmission or distribution of key signal (380/21)
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FOR148 • Having particular synchronization or initiation (380/48)
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FOR149 • Having digital signal handling (e.g., digital control, digital computer communication) (380/49)
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FOR150 • Including shift register or memory (380/50)
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