# Key Concepts

Understanding the DVR and its functionalities revolves around comprehending three fundamental concepts that form the backbone of the system. These concepts are integral to the operations of DVR running on zkPass Service and are crucial for anyone looking to effectively utilize or develop with this application.

1. [**User Data**](/zkpass/zkpass-developers-guide/zkpass-modules/dvr/key-concepts/user-data.md)
2. [**DVR (Data Verification Request**](/zkpass/zkpass-developers-guide/zkpass-modules/dvr/key-concepts/dvr-info.md)
3. [**zkPass Proof**](/zkpass/zkpass-developers-guide/zkpass-modules/dvr/key-concepts/zkpass-proof.md)

The diagram below illustrates the relationship among the three:

<figure><img src="/files/IQz2S5Av2lqTVAZiWJEY" alt="" width="327"><figcaption></figcaption></figure>

At a fundamental level, the user data and the DVR Info, which contains the query, act as essential inputs to the DVR/zkPass. These two components are necessary for the generation of the zkPass proof.

## <mark style="color:blue;">Pipeline for Generating zkPass Proof</mark>

For a more comprehensive understanding of the zkPass proof creation, examining the query processing pipeline provides insight into how this process unfolds.

<figure><img src="/files/5CD1lZpBTA47cKzUMKdx" alt="" width="375"><figcaption></figcaption></figure>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://gl-docs.gitbook.io/zkpass/zkpass-developers-guide/zkpass-modules/dvr/key-concepts.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.