---
title: "CID"
description: "Content identifiers for data the SDK has hashed."
source: "Integrity Python SDK"
---
A CID is a content identifier: a stable identifier derived from the content of a file, directory, or serialized object.

In `eqty_sdk`, CIDs are one of the core building blocks of provenance. Assets, computation inputs and outputs, and many low-level statements are connected through CIDs. If the content changes, the CID changes too, which is what makes it useful for integrity and reproducibility.

Most users do not create `CID` objects directly very often. Instead, they usually get them from asset constructors such as `Dataset.from_path(...)`, or from existing manifests and statements.

A simple wrapper around a content identifier (CID) string. Provides a typed wrapper for CID strings with property access and string conversion.

**Attributes:**

- [**cid**](#eqty_sdk_rustcidcid) (`str`) – The formatted CID string.

Creates a new CID, ensuring it is prefixed with `urn:cid:`.

## `eqty_sdk._rust.CID.cid`

```python
cid: str
```

The formatted CID string.