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Examples 35 to 40 in Annexure I of the CRI Guidelines 2025 illustrate the algorithm limb of section 3(k). Four are claims tied to specific technical components and are found patentable; two are generic procedures, a sorting method and a text tokeniser, found excluded as pure algorithms.
The Annexure applies the three-step test from paragraph 4.5.3.1: identify the steps, decide whether they are abstract or enabled with technical specifics, and conclude. Examples 35 to 38 (biometric authentication, video compression, a hearing aid, 5G packet routing) are not excluded because each is realised in named hardware and solves a real technical problem. Examples 39 and 40 (generic sorting and tokenising) are excluded because they are abstract sequences with no technical implementation. The Guidelines are the Patent Office's guidance and do not have the force of law; the Patents Act, 1970 and the Patents Rules, 2003 as now in force prevail.
The Office revises its guidelines, so check the current version on ipindia.gov.in. For the test itself see the algorithm exclusion article. A claim with a section 3(k) algorithm objection can be answered by a patent objection reply that matches it to the nearest example below.
What the Annexure is
Annexure I is described as a non-exhaustive indicative list of additional examples that illustrate allowable and non-allowable claims under the four limbs. The claims are invented by the Office and are not granted patents. This article summarises each in TaxClue's words.
The six examples
| No. | Field | Outcome in the Annexure | Deciding reason |
|---|---|---|---|
| 35 | Fingerprint authentication on a mobile device: a neural network extracts a feature vector in an isolated secure processor, the vector is encrypted by a hardware engine and matched against encrypted templates to grant or deny access | Not excluded | The algorithm is realised through specific hardware and software components (sensor, secure enclave, hardware encryption) and answers the real problem of protecting biometric data |
| 36 | Compressing surveillance camera video: a sensor captures frames, a hardware accelerator performs motion estimation, a standard codec is tuned for low latency, and the stream is sent wirelessly to a server | Not excluded | Each step is tied to a technical component, and the claim solves low-latency, bandwidth-efficient streaming; the algorithm is not claimed in the abstract |
| 37 | Noise suppression in a hearing aid: a microphone array, a digital signal processor running an adaptive filter, and an amplifier and speaker | Not excluded | The adaptive filter is a real-time process interacting directly with hardware to solve background noise in a medical device |
| 38 | Routing packets in a 5G network: a base station router uses live congestion metrics from edge nodes, applies a shortest-path method and updates routing tables as the network changes | Not excluded | The claim is integrated with real network infrastructure and metrics and solves a technical network problem |
| 39 | A generic sorting method: choose a pivot, partition, sort the parts recursively, combine | Excluded | A sequence of abstract steps with no technical implementation, integration or application to a real problem |
| 40 | A text tokeniser: scan for delimiters, split, output the tokens | Excluded | The same: abstract steps, no technical framework and no technical problem solved |
What the passing examples have in common
Looking across 35 to 38, the Annexure's step 2 reasoning lists the same kinds of feature each time.
- A physical or system component is named (a capacitive sensor and secure enclave; a camera sensor and hardware accelerator; a microphone array and signal processor; a base station router and edge nodes).
- The algorithm runs on that component and interacts with it, so it is not presented as a stand-alone procedure.
- The problem is technical: protecting biometric data, minimising delay over a limited wireless link, separating speech from noise, routing with low latency.
- The claim goes beyond a label such as "apply an algorithm": it says what the algorithm takes, from where, and what happens to its output.
What the excluded examples lack
Examples 39 and 40 are each a short list of procedural steps. The Annexure notes that they do not say how the steps are realised in hardware, how they are integrated with a system, or what technical problem they solve. It gives illustrations of what could have been added, such as use in database performance in a cloud environment or in a speech recognition engine, to show the kind of context that is missing. The reasoning ends that each is a pure algorithm "without technical enablement or application".
The lesson is not that sorting or tokenising can never be part of a patent. It is that the claim, on its own wording, must carry the technical context. A sorting method claimed as the way a specific memory controller reduces access time is a different claim from the bare method.
Using the examples in a reply
| Objection | Answer |
|---|---|
| "The claim is an algorithm" | Identify the components in the claim that carry out each step, as in Examples 35 to 38 |
| "The claim is an abstract sequence of steps" | Add the technical context from the description: the device, the data source, the problem solved |
| "Standard algorithm used" | A known algorithm can sit inside a patentable claim if its application is technical; point to the technical effect, as the Annexure does for shortest-path routing in Example 38 |
The paragraph 3.5.9 ruling in the Guidelines points the same way, that the inventive feature then lies in the implementation. See our article on the court rulings.
A worked example (invented)
Sangam Traffic files a claim to a method of finding the shortest route between two junctions using a graph search. The examiner relies on the pattern of Example 39. Sangam's description shows that the search runs on roadside controllers that receive congestion readings every few seconds and update signal timing. Sangam amends the claim to recite the controllers, the readings and the update of the timing, relying on the contrast between Example 39 and Example 38. The search method is unchanged, but the claim now ties it to equipment and a technical problem.
Common lapses
- Claiming a standard algorithm "implemented on a computer" with nothing else.
- Leaving the technical context in the description and out of the claim.
- Describing a hardware component as a "module" with no structure.
- Treating Examples 35 to 38 as a promise: they are illustrations of the test and every claim is judged on its own facts.
Need help with an algorithm objection?
If an examiner has called your claim an abstract algorithm, we can compare it with Examples 35 to 40 and identify which technical features need to be in the claim. See patent objection reply, and read next about the computer programme per se examples in the same Annexure.
Key takeaways
- Examples 35 to 38 are not excluded because each ties the algorithm to named hardware and a real technical problem.
- Examples 39 and 40 are excluded as pure algorithms with no technical enablement.
- The deciding feature is what the claim says about implementation, not the algorithm used.
- Known algorithms can appear in patentable claims.
- The examples are indicative, and the Act and Rules prevail.
Read next
- CRI Guidelines 2025, paragraph 4.5.3: the algorithm exclusion
- CRI Guidelines 2025, Annexure I: Examples 21 to 34
- CRI Guidelines 2025, Annexure I: Examples 41 to 50
- Software Patents in India: Can Software Be Patented
Disclaimer: Based on the manuals and guidelines published by the Office of the Controller General of Patents, Designs and Trade Marks that are named in the article, as consulted on 4 October 2026. They are guidance and do not have the force of law; the Patents Act, 1970 and the Patents Rules, 2003 as amended (including the 2024 amendment rules) prevail, and the current versions on ipindia.gov.in should be checked. This article is general information, not legal advice; check the official text before acting.