> For the complete documentation index, see [llms.txt](https://gl-docs.gitbook.io/zkpass/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gl-docs.gitbook.io/zkpass/zkpass-developers-guide/zkpass-modules/dvr/dvr-query/processing-query.md).

# Processing Query

## <mark style="color:blue;">Processing the DVR Query</mark>

zkPass Service processes the DVR query contained in the DVR Info and the user data referenced by the query in a pipeline flow, as depicted below.

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

1. **Initialization of the Data Verification Request(DVR)**\
   The proof verification begins by creating a Data Verification Request (DVR). This record is essential as it holds the specific request or "query" that needs to be verified.
2. **Inputs for Verification**\
   There are two key pieces of information that the DVR Query Engine requires to perform verification:
   * The **Query**: This is the request for information or action that needs to be checked.
   * The **User Data**: This refers to any information related to the user that the query will use or check against.
3. **Processing by the DVR Query Engine**\
   The DVR Query Engine is the powerhouse where the actual verification takes place. This engine operates within the Zero-Knowledge Virtual Machine (ZKVM), a secure environment designed for processing these queries.
4. **Results of the Verification**\
   Once the query has been processed, there are two results produced:
   * The **Zero-Knowledge Proof (ZK Proof)**\
     This is a verification result that proves the query was processed correctly without revealing any private details.
   * The **Query Result**\
     This is the outcome of the query after it has been processed.
5. **Packaging the Results**\
   Both the ZK proof and the query result are bundled into a single package known as the zkPass Proof object. This object can then be used to confirm the integrity and accuracy of the query process without exposing any sensitive information.