strongSwan

h1. Setting-up a simple CA using the strongSwan PKI tool

This How-To sets up a Certificate Authority using strongSwan [[IpsecPKI|PKI]] tool, keeping it as simple as possible.

h2. CA certificate

First, [[IpsecPKIGen|generate]] a private key, the default generates a 2048 bit RSA key:

<pre>

ipsec pki --gen > caKey.der

</pre>

For a real-world setup, make sure to keep this key absolutely private.

Now [[IpsecPKISelf|self-sign]] a CA certificate using the generated key:

<pre>

ipsec pki --self --in caKey.der --dn "C=CH, O=strongSwan, CN=strongSwan CA" --ca > caCert.der

</pre>

Adjust the distinguished name to your needs, it will be included in all issued certificates.

That's it, your CA is ready to issue certificates.

h2. End entity certificates

For *each* peer, i.e. for all VPN clients and VPN gateways in your network, generate an individual private key and [[IpsecPKIIssue|issue]] a matching certificate using your new CA:

<pre>

ipsec pki --gen > peerKey.der

ipsec pki --pub --in peerKey.der | ipsec pki --issue --cacert caCert.der --cakey caKey.der \

                                             --dn "C=CH, O=strongSwan, CN=peer" > peerCert.der

</pre>

The second command [[IpsecPKIPub|extracts the public key]] and issues a certificate using your CA. Distribute each private key and matching certificate to the corresponding peer.

h2. Install certificates

On *each* peer store the following certificates and keys in the [[IpsecDirectory|/etc/ipsec.d/]] subdirectory tree:

* *[[/IpsecDirectoryPrivate|/etc/ipsec.d/private/]]peerKey.der* holds the private key of the given peer.

* *[[/IpsecDirectoryCerts|/etc/ipsec.d/certs/]]peerCert.der* holds the end entitity certificate of the given peer.

* *[[/IpsecDirectoryCacerts|/etc/ipsec.d/cacerts/]]caCert.der* holds the CA certificate which issued and signed all peer certificates.

Never store the private key *caKey.der* of the Certification Authority (CA) on a host with constant direct access to the Internet (e.g. a VPN gateway), since a theft of this master signing key will completely compromise your PKI.