How Computers Use Hardware to Stop Software Piracy and Cracking
A 1982 hardware-based security system that prevents software from being copied or cracked by destroying sensitive data if the computer detects unauthorized access or execution.
Original patent title: “Computer systems to inhibit unauthorized copying, unauthorized usage, and automated cracking of protected software”
A 1982 hardware-based security system that prevents software from being copied or cracked by destroying sensitive data if the computer detects unauthorized access or execution. Granted to Individual in 1985 with 14 claims and 280 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This patent describes a computer architecture designed to protect software by keeping it encrypted while in storage and only decrypting it for execution within a secure hardware environment. The system uses a 'violation recognition' mechanism that monitors where instructions are coming from in memory. If the processor attempts to execute code from an unauthorized memory region, a 'destruction means' triggers to wipe the execution key and register data, effectively killing the process before a cracker can analyze it. It also includes a 'handshake' mechanism that allows legitimate jumps between authorized code segments while still preventing unauthorized access to the protected memory regions.
The gap
What does this patent NOT cover?
- Does not cover software-only copy protection schemes that lack the specific hardware-based destruction and translation mechanisms.
- Does not cover general-purpose encryption methods that do not involve the hardware-level monitoring of memory regions for instruction execution.
- Does not cover modern cloud-based licenselicensePermission from the patent owner to make, use, or sell the invention — usually in exchange for payment. Doesn't transfer ownership.Read more → verification systems that rely on external servers rather than internal hardware state destruction.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The system treats the processor's own registers and execution keys as volatile assets that must be physically wiped the moment a memory boundary violation is detected, turning the hardware into a 'self-destructing' security perimeter.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Hardware-based DRM (Digital Rights Management) modules
Trusted Execution Environments (TEEs) in mobile processors
Secure Enclaves in modern CPUs
Why it matters
The bigger picture
This patent represents an early attempt to move software security from the software layer to the hardware layer, anticipating modern concepts like Trusted Execution Environments (TEEs). It highlights the historical struggle to prevent 'automated cracking'—the use of software tools to reverse-engineer or bypass copy protection—by making the hardware itself an active participant in the security process.
Filed
September 20, 1982
Granted
December 10, 1985
Market context
Who's building on this
Companies in this space
Major semiconductor companies like Intel and ARM have integrated similar concepts into their silicon, specifically through technologies like Intel SGX and ARM TrustZone. These modern implementations build on the idea of isolating sensitive code and data from the rest of the system at the hardware level.
Market impact
This patent predates the widespread adoption of modern hardware-level security, but it set a precedent for the industry-wide shift toward integrating security features directly into the CPU. It helped define the architectural requirements for 'hardened' systems that can run proprietary software in environments where the user might otherwise have full administrative control.
Claim 1 — Plain English
What this patent covers
This patent describes a computer architecture designed to protect software by keeping it encrypted while in storage and only decrypting it for execution within a secure hardware environment. The system uses a 'violation recognition' mechanism that monitors where instructions are coming from in memory. If the processor attempts to execute code from an unauthorized memory region, a 'destruction means' triggers to wipe the execution key and register data, effectively killing the process before a cracker can analyze it. It also includes a 'handshake' mechanism that allows legitimate jumps between authorized code segments while still preventing unauthorized access to the protected memory regions.
The clever bit
The system treats the processor's own registers and execution keys as volatile assets that must be physically wiped the moment a memory boundary violation is detected, turning the hardware into a 'self-destructing' security perimeter.
What it does not cover
- Does not cover software-only copy protection schemes that lack the specific hardware-based destruction and translation mechanisms.
- Does not cover general-purpose encryption methods that do not involve the hardware-level monitoring of memory regions for instruction execution.
- Does not cover modern cloud-based license verification systems that rely on external servers rather than internal hardware state destruction.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Moderate
Citation count
40/40
Highly cited
Claim breadth
9/20
Moderate scope
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$72K – $230K
Midpoint $144K · expired or expiring · industry ×1.6
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
0 independent claims · 1 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
14 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Arnold, M. G., & Winkel, M. D. (1985). How Computers Use Hardware to Stop Software Piracy and Cracking (U.S. Patent No. 4,558,176). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/4558176/computer-systems-to-inhibit-unauthorized-copying-unauthorized-usage-and-automated-cracking-of-protected-software
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Computers Use Hardware to Stop Software Piracy and Cracking cover?
A 1982 hardware-based security system that prevents software from being copied or cracked by destroying sensitive data if the computer detects unauthorized access or execution.
Who owns patent US 4558176?
Individual owns this patent, granted in 1985.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 4558176 cited by?
This patent has been cited by 280 later patents that build on its ideas.
What problem does this patent solve?
This patent represents an early attempt to move software security from the software layer to the hardware layer, anticipating modern concepts like Trusted Execution Environments (TEEs). It highlights the historical struggle to prevent 'automated cracking'—the use of software tools to reverse-engineer or bypass copy protection—by making the hardware itself an active participant in the security process.
What does this patent NOT cover?
Does not cover software-only copy protection schemes that lack the specific hardware-based destruction and translation mechanisms.
Same assignee
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