Invalidity dossier
US 7606368
Method and apparatus for data encryption
Current assignee: L3Harris Global Communications Inc
Added 9/23/2026, 10:44:16 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 7,606,368 B2
Title: Method and apparatus for data encryption
Source: https://patents.google.com/patent/US7606368/en
Bibliographic data (as supplied): Application US11/498,037; filed 2006-08-03; published as US20070116271A1 on 2007-05-24; granted 2009-10-20; priority date 2001-06-29; inventor Michael Thomas Kurdziel; original assignee Harris Corp; current assignee listed as L3Harris Global Communications Inc. Legal status listed as "Expired – Lifetime," with adjusted expiration 2022-07-26. Classifications include H04L9/06, H04L9/0618 and H04L9/0637.
Purpose: The invention is directed to encrypting and decrypting blocks of digital data — specifically a cipher method and device for block-by-block conversion of a first digital block into a second digital block using at least one freely selectable control block, "with double the key length and significantly increased cryptographic strength while still providing a mode for inter-operability with prior art systems." A stated concern is that multiple encryption schemes require a cipher not be a mathematical "group," since a group cipher yields no security enhancement in multiple encryption.
Plain-language scope (from the excerpt): A block cipher device receives inputs X (primary traffic), Z1 (customer algorithm modification variable) and Z9 (secret Key), producing output Y. In the described 64-bit example, it has nine encryption stages plus a key scheduling unit. Stages 1, 5 and 8 perform modular addition, stage 12 also modular addition, stage 6 modular cubing, stage 7 a non-invertible "mid transform" mapping 128 bits to 64, stages 2 and 4 nibble-swap blocks controlled by bits of Z1, and stage 3 a customizable substitution/expansion block. The key scheduling unit deterministically generates pseudo-random patterns Z4, Z7 and Z8 from Z9. FIGS. 4–5 describe operation in Block Cipher Feedback Mode and Minimum Error Propagation Mode.
What the excerpt does not establish: The claim set is absent, so the precise legal scope of protection is not shown. The excerpt states the priority date and legal status are assumptions/not legal conclusions, gives no litigation, validity, or prior-art analysis, and note that the text was truncated mid-sentence regarding moduli choices.
Generated 10/1/2026, 9:33:11 PM
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Litigation summary
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Proceedings on file (0)
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No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.