> ## Documentation Index
> Fetch the complete documentation index at: https://cyborg-rid-of-c---conan.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Load Index

Loads an existing encrypted index and returns an instance of `EncryptedIndex`.

```cpp theme={null}
std::unique_ptr<cyborg::EncryptedIndex> 
    LoadIndex(const std::string index_name,
              const std::array<uint8_t, 32>& index_key,
              const std::optional<size_t>& max_cache_size = 0);
```

### Parameters

| Parameter        | Type                      | Description                                                      |
| ---------------- | ------------------------- | ---------------------------------------------------------------- |
| `index_name`     | `std::string`             | Name of the index to create (must be unique).                    |
| `index_key`      | `std::array<uint8_t, 32>` | 32-byte encryption key for the index, used to secure index data. |
| `max_cache_size` | `size_t`                  | *(Optional)* Maximum size for the local cache (default is `0`).  |

### Returns

`std::unique_ptr<cyborg::EncryptedIndex>`: A pointer to the loaded index ([`EncryptedIndex`](../encrypted-index)).

### Exceptions

<AccordionGroup>
  <Accordion title="std::invalid_argument">
    * Throws if the index name does not exist.
  </Accordion>

  <Accordion title="std::runtime_exception">
    * Throws if the index could not be loaded or decrypted.
  </Accordion>
</AccordionGroup>

### Example Usage

```cpp theme={null}
#include "cyborg_vector_search/client.hpp"
#include "cyborg_vector_search/encrypted_index.hpp"
#include <array>

// ... Initialize the client ...

// Create a secure 32-byte key (example: all zeros)
std::array<uint8_t, 32> index_key = {0};

auto index = client.LoadIndex("my_index", index_key);
```