> For the complete documentation index, see [llms.txt](https://docs.stacks.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.stacks.co/cookbook/clarity/cryptography-and-security/create-sha256-hash-clarity.md).

# Create sha256 hash clarity

{% code fullWidth="false" expandable="true" %}

```clarity
(define-read-only (create-sha256-hash (data (buff 4096)))
  (sha256 (unwrap-panic (to-consensus-buff? data)))
)

;; Example usage
(define-read-only (hash-message (message (string-utf8 200)))
  (create-sha256-hash (unwrap-panic (to-consensus-buff? message)))
)

;; Hash a simple string
(print (hash-message u"Hello World"))
```

{% endcode %}

### Description

Generate SHA-256 hashes from buffer data in Clarity smart contracts

### Use Cases

* Creating unique identifiers from data
* Verifying data integrity in contracts
* Implementing commit-reveal schemes
* Building merkle trees for proofs

### Key Concepts

* Takes a buffer as input (max 1MB)
* Returns a 32-byte buffer hash
* Uses `to-consensus-buff?` to ensure consistent encoding
* Produces the same hash as off-chain implementations


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## 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, and the optional `goal` query parameter:

```
GET https://docs.stacks.co/cookbook/clarity/cryptography-and-security/create-sha256-hash-clarity.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

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.