The PKIX certificate with racoon

Shoichi Sakane, KAME Project

$Id: index.html,v 1.2 2001/09/12 13:39:14 sakane Exp $

This document is obsoleted by the newer one. You must refer to the following: http://www.kame.net/newsletter/20001119b/ .

Introduction

This document is described how to use the PKIX certificate with racoon, IKE daemon. IKE allows to use several certificate for encryption and authentication. At the moment, racoon only supports RSA signature authentication method in all modes of phase 1 exchanges. For example, the certificates are exchanged by 5th and 6th messages in the case of the main mode. Both the initiator and the responder have to prepare own certificate before sending it. The certificate is placed to the certificate repository in PEM format. Racoon can get it from the local file system at the moment. SCEP may be supported in the future.
Racoon version is required kame-20000904-*-snap or later. But it is recommended to use latest version of KAME stack. Racoon leave all cryptographic algorithm with libcrypto.a of OpenSSL. The version is required OpenSSL0.9.5a or later is required. We don't support OpenSSL0.9.4. There are some trouble about X.509v3 certificate handling in OpenSSL0.9.4.

What can racoon do ?

Main/Aggressive/Base mode with RSA signature authentication.
X.509v3 certificate in PEM format.
Sending the certificate or not.
Getting peer's certificate in the local file system.
Verify the subjectName or the subjectAltName as the identifier.
Verify the issuer's chain or not.

Configuration

To use RSA signature authentication method, you have to define the following directives in a configuration file of racoon. For example, negotiation the IPsec keys with 194.100.55.1 (isakmp-test.ssh.fi), with UserFQDN "sakane@kame.net" as subjectAltNameas.

	path certificate "/usr/local/openssl/certs";
	remote 194.100.55.1
	{
		exchange_mode main;
		certificate_type x509 "sakane@kame.net.cert" "sakane@kame.net.priv";
		identifier certname;
		proposal {
			encryption_algorithm des;
			hash_algorithm md5;
			authentication_method rsasig;
			dh_group modp768;
		}
	}

The first line specifies the directory as the certificate repository to put all certificates. You have to put your certificate, your private key and all of issuer's certificate. In the following description, the directory is called "CERT directory" for convenience.
"certificate_type" directive specifies the type of certificate, and the both file name of own certificate/private key. You have to put them into CERT directory.
"identifier" directive specifies the ID value. It is carried onto the peer by ID payload. The peer may compare between the value and the subjectName (subjectAltName) in the certificate.
"authentication_method" direcivie specifies the authentication method in use. When you use a certificate, you have to define "rsasig".
If the peer don't send any certificate, you can get the certificate from your local disk. "peers_certfile" directive can allow it. If you don't want to verify the certificate, you have to set "no" into "verify_cert" directive. If you don't want to send the certificate, you have to set "no" into "send_cert" directive.

	path certificate "/usr/local/openssl/certs";
	remote 194.100.55.1
	{
		exchange_mode main;
		certificate_type x509 "sakane@kame.net.cert" "sakane@kame.net.priv";
		peers_certfile "isakmp-test@ssh.fi.cert";
		identifier certname;
		verify_cert no; 
		send_cert no;
		proposal {
			encryption_algorithm des;
			hash_algorithm md5;
			authentication_method rsasig;
			dh_group modp768;
		}
	}

To get your cert

This section is described how to get a certificate by OpenSSL0.9.5a.

Make a new private/public key pair. For example, 1024bits private key can be generated and stored into privkey.pem in PEM format by the following command:
```
  % openssl genrsa -out privkey.pem 1024
```

Make a PKCS#10 request, which is to be signed by your public key. The following example uses SHA1 as signature algorithm, RSA with 1024bits and stored into request.pem in PEM format.

  % openssl req -new -nodes -newkey rsa:1024 -sha1 -keyform PEM -keyout privkey.pem -outform PEM -out request.pem
  Using configuration from /usr/local/openssl/openssl.cnf
  Generating a 1024 bit RSA private key
  .........................+++++
  ........+++++
  writing new private key to 'privkey.pem'
  -----
  You are about to be asked to enter information that will be incorporated
  into your certificate request.
  What you are about to enter is what is called a Distinguished Name or a DN.
  There are quite a few fields but you can leave some blank
  For some fields there will be a default value,
  If you enter '.', the field will be left blank.
  -----
  Country Name (2 letter code) [AU]:JP
  State or Province Name (full name) [Some-State]:Kanagawa
  Locality Name (eg, city) []:Fujisawa
  Organization Name (eg, company) [Internet Widgits Pty Ltd]:WIDE Project
  Organizational Unit Name (eg, section) []:KAME Project
  Common Name (eg, YOUR name) []:Shoichi Sakane
  Email Address []:sakane@ydc.co.jp
  
  Please enter the following 'extra' attributes
  to be sent with your certificate request
  A challenge password []:
  An optional company name []:

Send the PKCS#10 request to the CA. Then retrieve your authorized certificate and stored into CERT directory. For example to use ssh certificate testing site. Connect to below URL.
```
	http://isakmp-test.ssh.fi/cgi-bin/nph-real-cert/cert.pem
```
And paste the content of request.pem. Don't forget to input your subjectAltName.
Alternatively, you can sign your certificate by yourself. For example, request.pem is a PKCS#10 request file in PEM format.
```
  % openssl x509 -req -in request.pem -signkey privkey.pem -out cert.pem
```

Issuer's certificate

You have to put some issuer's certificates into CERT directory. It is a unique method to save them in OpenSSL. For example, the filename of the certificate is ssh-ca1.pem. You have to type the following magic word after changing CERT directory.

  % ln -s ssh-ca1.pem `openssl x509 -noout -hash -in ssh-ca1.pem`.0