Demo Certificates for Californium

Californium's security module Scandium (Sc) is an implementation of Datagram Transport Layer Security 1.2, also known as RFC 6347. Scandium's test cases and many of Californium's examples that use security require some private and public keys for configuring DTLS.

This module provides some example Java key stores containing public/private key pairs and certificate chains to be used for configuring DTLS at the client and server side.

Included Keys and Certificates

The test cases for Scandium try to cover multiple setups regarding a reasonable PKI infrastructure. In order to do so, this module provides some sample keys and certificate chains contained in two Java key stores which can be found in the the src/main/resources folder.

We use a multi-level chain of trust as follows:

1. A pair of private/public EC keys along with a self signed certificate which together represent the root CA identity (alias "root").
2. A pair of private/public EC keys along with a certificate signed with the root CA's key which together represent an intermediary CA identity (alias "ca").
3. A pair of private/public EC keys along with a certificate signed with the intermediary CA's key which together assert the identity of a server (alias "server").
4. A pair of private/public EC keys along with a certificate signed with the intermediary CA's key which together assert the identity of a client (alias "client").

For extended tests, 5. A pair of private/public EC keys along with a certificate signed with the intermediary CA's key which together represent an second intermediary CA identity (alias "ca2"). 6. A pair of private/public EC keys along with a certificate signed with the second intermediary CA's key which together assert the identity of a server (large certificate, alias "serverlarge"). 7. A pair of private/public RSA keys along with a certificate signed with the root CA's key which together represent an intermediary RSA-CA identity (alias "carsa"). 8. A pair of private/public EC keys along with a certificate signed with the intermediary RSA-CA's key which together assert the identity of a server (alias "servercarsa"). 9. A pair of private/public EC keys along with a self signed certificate (alias "self"). 10. A pair of private/public EC keys along with a certificate using extended key usage for clientAuth, signed with the intermediary CA's key which together assert the identity of a client (alias "clientext"). 11. A pair of private/public EC keys along with a self signed certificate without signing usage (alias "nosigning"). 12. A pair of private/public EdDSA keys along with a certificate signed with the intermediary CA's key which together assert the identity of a client (requires java 15, alias "clienteddsa"). 13. A pair of private/public EC keys along with a certificate signed with the root CA's key which together represent an intermediary CA identity, same DN as 2., but with a different key-pair (alias "caalt"). 14. A pair of private/public RSA keys along with a certificate signed with the intermediary CA's key which together assert the identity of a server (alias "serverrsa"). 15. A pair of private/public RSA keys along with a certificate signed with the intermediary CA's key which together assert the identity of a client (alias "clientrsa").

Trust Store

The trustStore.jks contains the self-signed certificate for the root CA (alias root) as well as the certificate chain for the intermediary CAs (alias ca, carsa, and caalt). And a second intermediary CA (alias ca2). These certificates are used as the trust anchors in Scandium's examples and test cases.

The password for accessing the trust store is rootPass by default.

For platforms without jks support, a p12 trust stores is also generated. trustStore.p12, rootTrustStore.p12, caTrustStore.p12, caRsatrustStore.p12.

Key Store

The keyStore.jks contains the keys and certificate chains for the client (alias client, clientrsa, and clientext) and server (alias server, serverlarge, serverrsa, and servercarsa) identities.

The eddsaKeyStore.jks contains the keys and certificate chains for the client (alias clienteddsa) and server (alias servereddsa) identity.

The password for accessing the key store is endPass by default.

For platforms without jks support, a p12 trust stores is also generated. client.p12, clientEdDsa.p12, clientRsa.p12, server.p12, serverEdDsa.p12, serverLarge.p12, serverRsa.p12, and serverCaRsa.p12.

Tree of Certificates

(alias (CN))

                 +-- caalt (cf-ca)
                 |
                 |
root (cf-root) --+-- carsa (cf-ca-rsa) --+-- servercarsa (cf-server-ca-rsa)
                 |
                 |
                 |                       +-- ca2 (cf-ca2) --+-- serverlarge (cf-serverlarge)
                 |                       |
                 +-- ca (cf-ca) ---------+-- server (cf-server)
                                         |
                                         +-- servereddsa (cf-server-eddsa)
                                         |
                                         +-- serverrsa (cf-server-rsa)
                                         |
                                         +-- client (cf-client)
                                         |
                                         +-- clienteddsa (cf-client-eddsa)
                                         |
                                         +-- clientrsa (cf-client-rsa)
                                         |
                                         +-- clientext (cf-clientext)

self (cf-self)

nosigning (cf-nosigning)

Creating the Keys and Certificates

The key stores containing the demo keys and certificates can be recreated by means of the create-keystores.sh script. It uses the standard Java keytool to create keys and certificates.

You can also use the script to create your own certificates for use with Scandium. Simply alter the script at the places where you want to use other values as the default, e.g. your own distinguished names for the certificates and/or different key store names.

The script supports a list of tasks as arguments. The supported tasks are:

• remove remove all created files
• create create keys an jks
• export export p12 and pem
• copy copy pem files to californium-tests/californium-interoperability-tests and demo-apps/cf-extplugtest-server/service

If no argument is provided "remove create export copy" is used.

Note: to create EdDSA certificates, it's required to use java 15 (or newer). If previous java version are used, this client certificate is missing and the corresponding interoperability test is skipped.

Java 16 (or newer) - Keytool

The keytools of java 16 (or newer) uses a stronger encryption for the p12 (PKCS12) keystores. That stronger encryption can not be read by older java versions (7, 8, and 11). In order to support these older versions, the script uses

LEGACY=-J-Dkeystore.pkcs12.legacy 

Comment that out, and the strong encryption is use (and the p12 can not longer be read with java 7, 8, or 11).

Interoperability Tests With Gnu-TLS

If the interoperability tests with libcoap/gnutls are used, the ec-private keys must contain the public key as well (see gitlab - GnuTLS). This seems to require openssl in version 1.0.1. To apply that, docker and a ubuntu:trusty image may be used. That requires to install docker ahead. The create-keystores.sh script will then pull the ubuntu:trusty image, if docker is available. If successfully, the private keys are extracted in the proper format for GnuTLS.