What follows are the subclasses from one class of the Manual of Classification for US patents. As you scroll through the list and encounter a class/subclass of interest, you can jump back to the top and retrieve patent titles by entering the class/subclass in the box below.
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Class Number: 380 Class Title: CRYPTOGRAPHY Subclass Subclass Number Title 1 CRYPTANALYSIS 2 EQUIPMENT TEST OR MALFUNCTION INDICATION 3 STORED INFORMATION ACCESS OR COPY PREVENTION 4 .Digital data (e.g., software program protection, data encryption) 5 .Video 6 ELECTRIC SIGNAL MASKING 7 .Video 8 .By signal having discrete step amplitude variation 9 ELECTRIC SIGNAL MODIFICATION (E.G., SCRAMBLING) 10 .Video 11 ..Variable time delay modulation of baseband video signal 12 ..Carrier phase shift 13 ..Carrier frequency conversion 14 ..Nonstandard scan of video information 15 ..By modifying synchronizing signal 16 ..Record or coin controlled 17 ..Phase inversion of scan line information 18 ..Facsimile 19 ..Encrypting of accompanying audio signal 20 ..Control coding 21 .Having transmission or distribution of key signal 22 .With magnetic record carrier (e.g., tape, drum) 23 .With user or record actuated authentication 24 ..Electronic funds transfer (e.g., automatic teller) 25 ..Computer 26 .With mechanical control of signal encryption (e.g., cam) 27 ..By perforated record 28 .By particular algorithmic function encoding 29 ..NBS/DES algorithm 30 ..Public key 31 .Plural modulation of single carrier 32 ..Wobbling of carrier 33 .Using plural paths or channels 34 ..Plural carrier frequencies 35 .Variable time delay modulation 36 .Time segment interchange 37 ..Block/data stream enciphering 38 .Frequency shift or inversion 39 ..With plural band pass filters 40 .With plural band pass filters 41 .With quantizing and subsequent normalizing of signal (e.g., reentry telephone circuitry) 42 .Data stream/substitution enciphering 43 ..Key sequence signal combined with data signal 44 ..With particular key generator 45 ...Multiple key level 46 ...Nonlinear (e.g., pseudorandom) 47 ...Plural generators 48 .With particular synchronization or initiation 49 .With digital signal handling (e.g., digital control, digital computer communication)) 50 ..Including shift register or memory 51 .With production of printed copy (e.g., printer, typewriter) 52 .Including particular structure or housing (e.g., display, keyboard) 53 ..Audio transducer mounting or structure 54 BY MODIFYING OPTICAL IMAGE (E.G., TRANSMISSIVE OVERLAY) 55 WITH PRODUCTION OF PRINTED COPY (E.G., CRYPTOGRAPHIC PRINTER OR TYPEWRITER) 56 SELECTIVELY MOVABLE ELEMENT HAVING CODE CHARACTERS 57 .Rotatable 58 ..Characters on peripheral surface (e.g., cylinder section) 59 MISCELLANEOUS