> ## Documentation Index
> Fetch the complete documentation index at: https://docs.futurex.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Before you start

> Lists environment prerequisites and system requirements for OpenSSL Engine integration.

Verify your environment meets these requirements.

## Supported hardware

* CryptoHub `7.3.0.x` or later.

## Supported operating systems

* Linux

## Required access

* An account on the CryptoHub with administrator permissions to deploy new services.
* Local administrator/root access on the computer where OpenSSL Engine is installed.

## Network and firewall

* Allow outbound TCP port **443** from the computer running OpenSSL Engine to the CryptoHub REST API, specified by FQDN (for example, `cryptohub.example.com`) or CIDR (for example, `203.0.113.0/24`).

<Warning>
  TLS inspection or SSL proxies can break mutual TLS handshakes. Exempt the CryptoHub FQDN(s) from inspection. Configure the CryptoHub with a FQDN so the exemption applies.
</Warning>

## Other

* OpenSSL 1.1.x or 3.x using the ENGINE interface. On OpenSSL 3.x, Futurex recommends the OpenSSL **provider** path instead; use this ENGINE path for OpenSSL 1.1.x or where an existing application still relies on the engine interface.
* OpenSC and libp11 0.4.21. Earlier libp11 builds can fail when OpenSSL 3 loads a CryptoHub-backed key through ENGINE.